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ChromaTalk Archives: December 2009

Re: Progress with my Chroma!

Go to first message in thread, November 2009

Frank McGing [21010198]

Hi Paul

Many thanks for your help! I should clarify the following:

Also, the lower display is missing rather a lot of segments.

Really? But none of them were missing in the 01234567? All of the segments appear in at least one of those digits, so that means the segment (anode) drivers all work. And since all of the digits showed something, that means the digit (cathode) drivers all work. The only other possibility is that some of the actual display segments have failed, which is something I've never seen. But you could scrounge the display from the other board if that's the case.

All digits are working, but several digits are missing segments, if that makes sense. for example, '03' is appearing as 'U' followed by an upside down 'F'. Anyway, I am now about to start by replacing Z25 (TL081) to see if that improves the situation.

Paul DeRocco [21030230]

It sounds like the display itself is bad. Whether it's possible to pry the lens assembly off and resolder the individual digit chips, I don't know, but it could be a fun experiment. Might totally destroy it. But at least you have another display on the other board. Those old-fashioned 7-segment LED calculator displays are virtually impossible to find nowadays.

Once you get the DAC working properly, that may just bring the instrument to life. But if experience is any guide, you may find some channel boards in need of repair, too. Bad 4558's, leaky 4051's, etc. Good luck.

Frank McGing [21010198]

...it's most likely a burned out Z25, the TL081 op-amp, but it could also be the DAC itself if it's totally fried.

And it was indeed a fried DAC! I changed Z25 with no success, then swapped in Z20 (AD7523) from the original I/O board and bingo - Chroma 21010198 is alive again! :-) Ok, it's only tuning a couple of voices, and it's rather hit and miss which ones it decides to tune on any given boot, or after a SET SPLIT 50, but I spent some time playing it when it tuned 3 voices properly, and I must say I'm blown away by how beautiful it sounds.

So now it's time to pull out all the voice boards and figure out which ones are good and bad. But - the sound! Wow!

A very happy
Frank

Chris Borman [21030194+]

What is it with blowing the DAC when replacing the PS? The two times I've swapped Power Supplies the DAC toasted. Maybe an alt gnd path running high current through it?

Heinz Weierhorst [21010276]

Hi.

I remember that was discussed at Chromatalk a time ago. All grounds must tied together to one rail i.e. the back panel. Forgotten to reskrew channel motherboard's ground? It was something like that - please read.

Paul DeRocco [21030230]

Probably. The DAC gets its ground from the Channel Motherboard, so that its output voltage will be referenced to that ground. There really should have been some back-to-back diodes between that line and the local ground, for protection.

Paul Tillotson [21030218]

Progress with my Chroma!/DAC Failure W/New PowerSupply

Is this known to be happening frequently after replacing power supplies? And it's known to be caused by improper ground lines? And the symptoms in this case were that the Chroma failed to go into autotune, and all voices were disabled but the instrument still responded to patch and parameter changes? Or was that it was more a case of everything locked up and no response at all from any panel changes? The fix was replacing one chip, the Z20 (AD7523)? Is it socketed and easy to find?

Sorry for all the questions but it might be good to tie up all the pieces of this discussion if it's a known problem. After swapping out power supplies my Chroma now fails to go into autotune but still does patch and parameter changes. I was thinking it was a case of the voice cards being too far out of tune but when I tried to go through the tuning procedure on each voice card, I was flummoxed by lots of erratic tuning behavior and probably made the tuning issues worse.

Paul DeRocco [21030230]

Re: Progress with my Chroma!/DAC Failure W/New PowerSupply

Is this known to be happening frequently after replacing power supplies? And it's known to be caused by improper ground lines? And the symptoms in this case were that the Chroma failed to go into autotune, and all voices were disabled but the instrument still responded to patch and parameter changes? Or was that it was more a case of everything locked up and no response at all from any panel changes? The fix was replacing one chip, the Z20 (AD7523)? Is it socketed and easy to find?

I'm not a tech, so I don't have experience with dozens of Chromas, but it's obvious that the DAC is susceptible to damage if the unit is powered up with the Channel Motherboard disconnected from the I/O board. Other than that, I don't see any problem in the design.

I don't know how many units were built with sockets for the DAC or other ICs. As I recall, that was something we did back at ARP and Fender on early units, until we had confidence that the design was reliable.

If you need to buy a replacement DAC, Digikey stocks the AD7333L for $9.30, which is an acceptable substitution. I wouldn't scrimp and get the K or J version—they'll degrade the tuning accuracy.

Sorry for all the questions but it might be good to tie up all the pieces of this discussion if it's a known problem. After swapping out power supplies my Chroma now fails to go into autotune but still does patch and parameter changes. I was thinking it was a case of the voice cards being too far out of tune but when I tried to go through the tuning procedure on each voice card, I was flummoxed by lots of erratic tuning behavior and probably made the tuning issues worse.

There are so many things in the chain that can screw things up that it really takes a scope and some understanding of the circuitry to diagnose the problem. You might get lucky and find something amiss with a voltmeter, or by swapping socketed parts, but that's not generally the case.

Frank McGing [21010198]

It gives me great pleasure to announce that Chroma 21010198 is now fully functional, and tuning all 8 voices!

The breakthrough happened late last night - I decided to go back to the original Rhodes I/O board, as the ARP one I recently purchased on eBay had issues with missing LED segments and unpredictable tuning. The problem turned out to be the 0809 A/D (Z3). I swapped Z3 over from the ARP I/O board, and my Chroma fired up immediately! Apart from replacing the original PSU with Luca's SPSU, this was the only problem.

Many thanks to all who helped - I'm very happy to be part of such a great community!

I can't wait for my CC+ and pressure sensor kit! And definitely count me in for a knob box... :-D

Jesper Ödemark [21010135]

Frank McGing skrev:

It gives me great pleasure to announce that Chroma 21010198 is now fully functional, and tuning all 8 voices!

Great news after all fuzz and today's negativism on the list [see Rhodes Chroma REV 14 & 3 on Ebay below] - congrats! :D

21010135 sends her greetings!

Frank McGing [21010198]

Thanks! I thought it might be an appropriate time to post some good news... ;-)

Speaking of which, I'd like to add that I'm also a regular reader of Matrix's blog. So, to Matrix and Chris (for creating and maintaining the best resource of its kind) - keep up the good work, it's very much appreciated.

Re: Chroma Pressure Sensor Project update

Go to first message in thread, November 2009

Dave Manley [21030547]

Hi Chris,

Sign me up. Do you want immediate payment?

Chris Borman [21030194+]

Sure Dave! I'm waiting to invoice folks until after I recive lead time from Sensitronics. Should be just another day or two.

Jesper Ödemark [21010135]

Sure Dave! I'm waiting to invoice folks until after I recive lead time from Sensitronics. Should be just another day or two.

This time I'll let you guys iron out the flaws of this cool Chroma update before I jump this train. Looking forward too though, and also to seeing the CC+ upgrade that'll turn the Chroma into one vicious masterkeyboard and not just an amazing synthesizer.

So, Chris, if you keep track on a "2nd batch" already, sign me up there...

Tom Hughes [21030251+]

I see the Pressure Sensor Retrofit Kit page posted on the Rhodes Chroma website. So, is it officially in production now? Chris B, please let me know when you need payment. My figured Bubinga-cased Chroma eagerly awaits...

Ron Joseph [21030042+]

I'd love to see a pic of the bubinga wood Chroma..:)

See bubinga chroma and expander below.

Chris Borman [21030194+]

Chroma Pressure Sensor Project webpage and update

Yes! A page has been dedicated to the Chroma Pressure Sensor Kit. Of course much appreciation and thanks to Mr. Ryan for doing this. I feel honored to contribute to such an incredible collection of information!

To update the progress, Sensitronics said 3-4 weeks lead time for the sensor, so 4-5 weeks to complete and ship. In the meantime I need to order parts, build up the PCB's, cables and sensor assembly and verify the installation instructions. Once installed, I will check sensitivity and make adjustments to the Op Amp circuit if necessary. So I think we're good!

I have everyones email address and will invoice in the next couple days through PayPal to get started.

Keith Hendricks

Re: Chroma Pressure Sensor Project webpage and update

Chris,

Is the pressure sensor something that a trained technician has to install or is the installation relatively simple?

Chris Borman [21030194+]

Re: Chroma Pressure Sensor Project webpage and update

It's really plug and play. Read the instructions and let me know what you think. The only critical task is ensuring the sensor is centered with the key (weight) contact.The sensor is peel and stick and circuit boards wood screwed to the damper bar and cabled together and to Chroma J22. That's it!

BTW, seems there is always someone monitoring the discussion ready and willing to offer help!

Dave Bradley [16330135]

Re: Chroma Pressure Sensor Project webpage and update

Chris,

This is a super project and I hope to support it by obtaining a pressure kit. The thing is, I'm broke right now and my Chroma is dead anyway. Do you think there will be a second round of these, or will I miss the boat if I wait?

Chris Borman [21030194+]

Re: Chroma Pressure Sensor Project webpage and update

Hi Dave,

Not a problem. I imagine there will be interest for a follow on production run.

Jesper Ödemark [21010135]

Re: Chroma Pressure Sensor Project webpage and update

Sorry for acting like a parrot... but please put me on the "B-list". :)

Chris Borman [21030194+]

Re: Chroma Pressure Sensor Project webpage and update

You're noted for run #2!

Luca Sasdelli [21010226]

Re: Chroma Pressure Sensor Project webpage and update

Hi Chris,

I'd like to subscribe for a pressure sensor kit. Am I still in time to advance payment or should I wait for the next batch?

Tom Hughes [21030251+]

I'd love to see a pic of the bubinga wood Chroma..:)

Me and my big mouth... Yes, I had matching custom cases built for my Chroma and Expander. My apologies to Chris Ryan for not sharing the news sooner. I was waiting until I could give it a good write up with nice pictures to match, but I haven't gotten to it yet. I guess I'll have to put that on the short list now...

See bubinga chroma and expander below.

Ron Joseph [21030042+]

Totally understand ;) When I had mine redone in Zebrawood I waited until I had some good shots to show her off. If I ever am lucky enough to own an expander I'll have a matching Zebrawood case made as well.....Ron

Tom Hughes [21030251+]

I actually got the idea from seeing your Zebrawood Chroma! But I didn't want to use Zebrawood... that'd make me a copycat (heh heh).

Peter Forrest [21010096]

Can I ask you guys (if you don't mind) how much it cost you to get a chroma re-cased in exotic wood?

Tom Hughes [21030251+]

Mine came pretty close to $800 (for both). But I figured it was the kind of thing you only do once, so...

Ron Joseph [21030042+]

I did mine through Jesse Moffat at Cantos while JL was working on the electronics. I don't recall how much it cost; just that it seemed reasonable at the time. I'm very glad I did it.

I should repost pics of both of mine at this point. The Zebrawood now has a "Halloween" membrane panel and my other has the Gold Membrane panel. The second is currently in pieces as I lent my CC+ board to a friend. I need to install the power supply kit I purchased a while back as well as sand down the case to a narural color to match the new panel...

Peter Forrest [21010096]

Thanks.

In the UK, Jeff Toman at customsynth would probably do a good job. I guess it might be 300-350GBP, which is about $500-550 US, I guess.

Luckily my case is pretty OK, so I don't need to do anything except maybe sand it down and wax it or something.

Dave Bradley [16330135]

There is a respected tech here in the states (Wes Taggart) that offers a replacement hardwood set in various woods for a Chroma case, and would do one for Expander as well.

Bottom of this page.

See also Re: Pressure Sensor and Rhodes Chroma CPU Plus (CC+) below.

Chroma's unique sound

Eric Inglebert [21030075]

Dear Chroma users,

I'm new to this great community and very happy to own this great and unique instrument.

The feel and sound character is very different from all the stuff I have (Prophets, OBs, PPG, Synthex, JPs) and can only be touched by the Memorymoog imho. It's sounding more like a discrete components synth than a Curtis ICs based one. There is an organic character in the VCO section with this incredible pulse wave conception. Multiple signal paths, filters and modulations capabilities are also outstanding.

Speaking of CEMs, I'm currently looking for CEM3350s or dual voice boards, if anyone could help...

Heinz Weierhorst [21010276]

Hello Synthwalker.

I do agree with you. This synth is unique! The CEM3350 design is unique too, never seen in other filter chips. But best of all how the filter design was done by the ARP people. It differs total from app.notes in CEM3350's datasheet. Here a source for one CEM3350: Curtis CEM3350 | TBS Shop But it is used and they want € 99,- which in my opinion is overpriced.

Chroma Knob Box

Frank Hettlich [21030041+]

With all the recent posts about the Pressure Sensor Project and beautiful custom cases (I am quite happy with my completely refurbished original wood of my 2 Chromas) I still miss ONE essential piece in the glorious Chroma World - a Chroma Knob Box

I know it has been discussed several times in the past but I would be VERY, VERY happy if someone would offer a nice user interface with knobs and/or sliders and switches. No, I do not like 3rd party boxes...

And I assume that Chroma owners (like me) are probably willing to pay good money for it, given the prices they have already spent on the

Any chance someone will finally "trigger such a project"?

Peter Forrest [21010096]

Yes, I agree it would be great!

Frank Hettlich [21030041+]

My guess is that at least 50-100 knob boxes could be sold within a 1 year time frame as people might be even more interested in such a thing than in other "add-ons". And dealers (Analoguehaven, Schneidersbuero) might also want to distribute it. It would be the final piece added to THE polyphonic synthesizer of the last 30 years!

Marais

we, concur!!

Doug Terrebonne [21030114]

Do you really need a dedicated box? Why not spend $100 or so and get something like a Behringer BCR-2000 and use it with a CC+ Chroma?

Marais

Using Behringer on Ferrari ?

Why not just use Pine for the case : )

Frank Hettlich [21030041+]

Doug,

in case of the Chroma I see a dedicated knob box as the appropriate way to honor this instrument. Enthusiastically said it is the "polyphonic Buchla"...

I could explain in lenghty details why the visual appearance of an instrument does matter for me but it is all said/discussed on various forums like muffwiggler.

E. g. I find myself always attracted by the Memotron that LOOKS and SOUNDS awesome (did a test with my girl-friend recently who was literally "blown away" by the sound of the original TD flute processed by a cheaply vintage sounding DD-20) and resist playing with the Andromeda as it hurts my visual senses being painted in the ugliest grey tones people have ever used for a synth...on the other hand the Buchla 200e is the most visually pleasing musical device I have ever come across (lots of "Buchla at night" pics around), the sound is a matter of taste...

I love listening to the ARPish Chroma sound and playing the phantastic keyboard but shortly after some editing I feel frustrated to do so as there is a constant barrier between my ideas and what I have to do to achieve my goal.

Ok, I could do it with a Behringer BCR but I prefer a tool shaped and be part of the Chroma "instrument" (completely irrational I admit).

If we - as human beings - only decide on ratio (max functionality for the best price) life is "grey" (at least for me).

Michael Salmon [21030155]

Where do people stand from a price sensitivity perspective for both a kit and/or ready-made box? $250-$750?

Randel Osborne [21030467]

All-

I'm currently in the process of building a large, dedicated knob box with knobs for all parameters, and art that faithfully honors the look of the instrument.

I have a mini-prototype running at the moment, and I'll share some details and photos later this month.

Frank Hettlich [21030041+]

GREAT!

Any chance it does not have the uniform "military" look some manufacturers use on their modules, e. g. 5 rows each having 20 knobs and the same spacing?

Frank Hettlich [21030041+]

Where do people stand from a price sensitivity perspective for both a kit and/or ready-made box? $250-$750?

If it is nice $500 would be ok!

Jesper Ödemark [21010135]

Frank Hettlich skrev:

- a Chroma Knob Box ... Any chance someone will finally "trigger such a project"?

With the arrival of the acceptance of CC my guess is that slaughtering a 3rd party unit, making a neat Chroma-styled panel and cherry end cheeks would be the best and cheapest option.

I still nourish my own plans to make a Chroma styled sticker to apply to the front panel of my Drehbank and then finish it off with cherry wood since there are even pre-drilled holes intended for rackmounting and similar. I guess I need better looking knobs though. In blue and green maybe...

But the coolest solution would be a new right side panel with push-knobs instead of the membrane switches. Choose memory location and functions by pushing and adjust settings by turning. That's look and feel great I think. :)

You could always store the original panel inside somewhere if some future owner thought it was a bad move...

Jesper Ödemark [21010135]

Using Behringer on Ferrari ? Why not just use Pine for the case : )

Hey, both my SEM and slaughtered MS-10 have pine panels. :P

Luca Sasdelli [21010226]

Hey, both my SEM and slaughtered MS-10 have pine panels. :P

Wow! The floor too... :-)

Jesper Ödemark [21010135]

It's Sweden you know... One third of this country is covored in it. And by that I mean the the vertical type. :) Though that crap is some laminated and sorry excuse for a wooden floor. And it's not pine... :)

Matt

I will pay very good money for a well laid out knob/slider box.. I would even outlay a deposit in advance to help development! Something like the Jupiter-8 layout would be wonderful, and would make the Chroma perfect.

Randel Osborne [21030467]

Frank-

Here's an example of some preliminary art for the project - I've tried to capture the spirit of the Chroma aesthetic.

I intend to have the box stretch the full width of the Chroma, so it will be wider and shorter than my art, and wrapped in a cherry box.

There is enough space to accurately label every parameter, as well as depict the 16 patch structures as well as the Set Split functions (including CC+)

I'm now experimenting with the integration of a display to give the user feedback of a particular parameter's value, as the knob and markings may not have enough resolution to set things like PITCH-Tune.

More information (and higher resolution art) to follow.

Rob Belcher [21030095+]

This is such a cool idea, lets face it the Chroma is a pig to program... I would pay upfront too for something like this (for my Chroma Expander)

Tom Hughes [21030251+]

I have nothing to offer in the way of assistance with the design aspect, but I do own and operate a business of manufacturing guitar effects pedals, among other things. So I'd be happy to offer our services in building a production run of Chroma Knob Boxes once it's designed (and frankly, we could use the work). I already mentioned this to Randel, as he lives less than half an hour away from our shop.

Marais

You should consult David Clarke as well, who has a working knob box he had designed and uses and looks great from what I remember.

I would also put a deposit on something like this as long as it matches the classy aesthetic of the Chroma, USES SMOOTH, good pots that don't fail easily, tests and works reliably, and does not take years to finish. Would be happy with a price range of $300-750.

Paul DeRocco [21030230]

This is such a cool idea, lets face it the Chroma is a pig to program... I would pay upfront too for something like this (for my Chroma Expander)

Personally, I think I'd rather have a tablet PC with a touch screen, and some clever software. Admittedly, an "obvious" interface of a screenful of virtual sliders would suck, because there isn't enough room on the screen, but there are cleverer ways to organize an interface. And I'll bet a box of knobs made in small quantities would wind up costing more.

...unless you want a piece of furniture that matches your Chroma. ;-)

Andrew Dalebrook [21010180]

Knob Boxes

I'd say the simplest way to go about this would be to use the MIDIBox format [see also the MIDIbox Forum]. Quite simply, one can solder kits.
  • You use DIN modules for digital inputs e.g. switches or rotary encoders
  • DOUTs are for LEDs
  • AIN for analog pots or CV
  • AOUT for controlling CV (12-bit DAC, could use to increase resolution of some parameters?)
  • LCDs are supported
  • "Maps" (e.g. presets) can be stored on EEPROM (24LC512 or 256)

Every thing connects back to the Core (PIC based) which contains MIDI in and out.

Firmware is already written, and can be updated via MIDI when the PIC is burned with a bootstrap loader (chips are available pre-burned).

Connect everything up and program in each knob to control the desired parameter (CC, NRPN, Prog. change etc.). A GUI is available. It would also be possible to save costs and/or space by assigning one knob to (selectable) multiple sources You'd need a MIDI interface or CC+ to make this work without a lot of complexity.

The "hardest" part is making a panel; you can do this via Front Panel Express for metal or Ponoko for acrylic.

If enough people were in, the costs would be greatly reduced.

By definition, the MIDIBox project is not-for-profit, as much time and money has already been invested for free.

Thomas Story [21030352]

I know this is probably outside of the realm of reality, but how awesome would it be to have an entire new front panel designed to replace the membrane panel with one that has switches instead and rotary knobs in the space right above the switches. Obviously that would be a huge undertaking and probably not possible but it would be pretty amazing to have all knob switches and sliders built in.

Marais

Re: Knob Boxes

I am a musician, songwriter and programmer, and have absolute no interest in soldering a kit or programming from a computer. Give me knobs or give me death.

Marais

On Dec 9, 2009, at 9:25 AM, Randel Osborne wrote:

Here's an example of some preliminary art for the project - I've tried to capture the spirit of the Chroma aesthetic.

This is really nice Randel. Of course standard wood sides as well please : )

Arun Majumdar [21030348]

Count me in for a Chroma Knob box --- I am keen on this.

Frank McGing [21010198]

I would also be interested in a Chroma knob box.

Chris Ryan [21030691]

On 2009-12-09, at 10:28 AM, marais wrote:

You should consult David Clarke as well, who has a working knob box he had designed and uses and looks great from what I remember.

See ChromaKnob (Chroma Knob Box) for pictures and information.

Matt Thomas [21010021]

For this price the Mackie C4 Pro looks an almost perfect answer.

Has a few features that I would consider a must for a Chroma controller - LED-ring encoders (for at-a-glance parameter values), LCD displays, and (my personal favourite) text value tables. This means that not only can you define your own text for the LCD of each controller (e.g. 'Sweep') but you can define text for each value i.e. instead of displaying the different Sweep values as 1, 2, 3, etc the LCD can show Sine, Cosine, Offset, Half, Tri A, Tri B etc. Would remove the need for endless cross-checking against the Chroma parameter chart that still dogs most hardware controller solutions.

To seriously consider a custom Chroma knob box I'd be looking for these features.

John Simmons [21030454]

Re: Knob Boxes

I would love to see a knobbox not too dissimilar from David Clarkes - as featured on the Chroma site.. Ie, nice aesthetics and lots of dedicated/assignable kobs (or sliders.) I would certainly buy one, i think the costs mentioned so far in this thread seem reasonable..

Ron Joseph [21030042+]

Re: Knob Boxes

Perhaps Dave or some of the other more tech savy individuals could discuss how difficult would it be to replace the front panel. If we're able to control al functions via a knob box couldn't we just graft that knob box to the space that's currently occupied by the membrane panel?

Arun Majumdar [21030348]

Re: Knob Boxes

In my case, I would prefer to retain my original Chroma front panel. Since I have two Chroma's I could actually lift out the front panel from one of them --- however, I'm still uncertain if I would want to do that (unless the membrane panel fails to work entirely, then this is the best solution: replace it with a knob-box panel).

Therefore, if enough people want the form-fit factor to match the current Chroma from panel size (so it can be replaced) I would suggest two versions, of identical size to the Chroma front panel --- just that one is mounted in its own enclosure and the other would be your own DIY for mounting in the Chroma --- in other words, I would not make a kit for folks lifting out the front panel, but would make it the knob box the same size so that if they did lift it out, they could drop the knob box in as their own custom DIY project.

Eric Inglebert [21030075]

Re: Knob Boxes

The knobby integrated front panel is definitely a must... ;-)

Tom Hughes [21030251+]

Re: Knob Boxes

That looks like a P5 Photoshopped onto a Chroma... Oh, and NICE COLLECTION!

Eric Inglebert [21030075]

Re: Knob Boxes

Not a P5... ;)

Chris Borman [21030194+]

Re: Knob Boxes

Looks like you got ahold of the T8 minus keyboard that Synthwood has on their website!

I like a knobby FP and this Knob Box discussion really got my synapses sparking this morning! I want a sleek looking, plug-in solution compatible with and augmenting existing h/w. Each knob should be easily accessible and 100% active during performance along with the existing controls. I happen to love the look of the Chroma front panel and think any solution should take advantage that. I propose an array of low profile rotary encoders mounted just below the existing program/parameter select switches topped with .500 dia. flat black alum metal knurled geometric knobs. Two issues - One is the knob will slightly interfere with pressing the existing membrane switches. At normal playing the front panel angle will necessitate that you lift your finger up and over the knob to press the switch. Not deal killer and the encoders can be ordered with an internal switch so you could alternately just press the encoder knob. Issue # 2 is the knobs will have minimal separation being mounted directly under each embrane switch so you may hit the adjacent knob if you've got big nubs. I do and will need to build up a section and give it a try! The encoder array would plug between the existing membrane-i/o board mux and the data slider-ADC h/w. A micro would monitor the existing membrane switches and data slider and encoder array and transparently present that info to the Chroma scan and ADC h/w. A digital pot would be used to emulate the data slider. The encoder assemblies would be built up on a low profile Chroma angular and color matched black bezel'd PCB strip. It could be sticky tape removable (I like sticky tape). To give the micro a bit more to do, the bezel assembly could include miniature LEDS below each encoder to indicate the last parameter you fiddled with. A dim-able 2mm electroluminescent wire mounted to illuminate the parameter text on the membrane (and not blind you). Could tap into the Program/Parameter switch to one touch auto select the Program mode by a press or Param mode by a spin. Anyway, that's what I thought up this morning and is the next project for my Chroma!

Paul DeRocco [21030230]

Re: Knob Boxes

You'd have to make completely new membrane switches. Currently, the switch pads are "wired" up with silver traces that don't carefully avoid where you'd like to drill holes through it.

Also, when you actually try to build it, and figure out how much it costs just to break even, paying yourself $0/hr, you'll see why we opted for membrane switches at ARP in the first place.

But as a labor of love, it could be a cool project. Go for it.

Robb Witt

Re: Knob Boxes

Indeed. As Paul notes, when Warren laid out the traces for the membranes... dodging retro-fit rotary pots was not in the cards. We actually thought we were doing something fairly slick!.

Chris Borman [21030194+]

Re: Knob Boxes

I agree that Membrane switches are less expensive. I never liked the non-tactile part of membrane switches until I used them on the Chroma with the Tapper. What a great idea! I really like the look of them though in both the Chroma and Quadra. In quantity the encoders are a few bucks each, times 50 of course. The luxury knobs are even more than that and the PCB may cost a bit at such a length so yea, cost will be upwards of $500-$600. The solution I have does not touch or effect operation of the existing membrane - No holes at all. The low profile encoder array strips litterally stick on top of the front panel. The Micro/Mux board would be mounted below somewhere and membrane tail would be plugged into it, the micro/mux back into the Chroma. Still have to figure out where to run the cable from the encoder arrays to the micro. Probably off to the side some where.

Of course absolutely a labor of love!

Chris Borman [21030194+]

Re: Knob Boxes

Indeed. As Paul notes, when Warren laid out the traces for the membranes... dodging retro-fit rotary pots was not in the cards. We actually thought we were doing something fairly slick!.

I love the way you guys engineered the Chroma. Very nice! I considered going through the FP but can't see a thing under there so that would have no doubt destroyed circuitry. Could go that route with the encoder/integrated SPST pb switch that could duplicate the function of each membrane sw.

Paul DeRocco [21030230]

Re: Knob Boxes

I agree that Membrane switches are less expensive. I never liked the non-tactile part of membrane switches until I used them on the Chroma with the Tapper. What a great idea! I really like the look of them though in both the Chroma and Quadra. In quantity the encoders are a few bucks each, times 50 of course. The luxury knobs are even more than that and the PCB may cost a bit at such a length so yea, cost will be upwards of $500-$600. The solution I have does not touch or effect operation of the existing membrane - No holes at all. The low profile encoder array strips litterally stick on top of the front panel. The Micro/Mux board would be mounted below somewhere and membrane tail would be plugged into it, the micro/mux back into the Chroma. Still have to figure out where to run the cable from the encoder arrays to the micro. Probably off to the side some where.

You can get some Panasonic rotaries from Digikey for about 50-60 cents in quantity, but their feel isn't that wonderful.

Michael Salmon [21030155]

Re: Knob Boxes

anyone know where you could get a custom shape multi-touch screen (any resolution)? I'm imaginging the cubase editor UI on a touchscreen with some custom software running locally so it doesn't need a PC. it's about 20" wide, 8" tall from the jpg.

this is the closest I can find

eBay item #230410838541

ribbons would be nice, but indicating the value would be tough. LEd, LCD, hologram, ugh. How to Build a 2 Note Ribbon Controller

it's fun thinking about this, tough seeing it to reality.

David Clarke [21030085++]

Folks - in the Winter of 2006 I figured I'd look to see how much it'd cost to make a new version of the one-off ChromaKnob.

The idea was to simplify the electronics (do everything with a PIC) and put it all on a circuit board, to see if it was actually viable to perhaps build a few for folks. It would also have a larger display (4 lines vs. two) to show more information.

I got a metal panel made, had a colour overlay for it, and got it up and running.

Once I saw the costs (and suffered through hand-wiring the first one) - I never seemed to get the time or the inclination to get back to it to add any additional features or to put it in a box.

For what it's worth to the current discussions, the attached .pdf outlines the general layout I used at that time (thanks to Chris Ryan [21030691], for his input at the time).

The different routings possible are listed across the top, with the idea that an LED would illuminate beside the patch structure that is active on the Chroma.

Communication from the panel to/from the Chroma is via the Chroma Port.

As has already been discussed, the driving costs are in the 'multiplicity' of the pots/encoders. In addition to the cost of the actual pots/encoders, you'd also need to include the cost for the knob-caps.

You also have to factor in the cost for a solid panel (something firm enough to securely hold the knobs/sliders/what-have-you) and the extra cost for either a silk-screen, or a panel overlay.

If you went to a large circuit board to hold the encoders, then size means cost.

Also, if you went to a wood enclosure - then again larger size = more cost.

I think in addition to knobs you would still need some sort of visual indication. I went for an LCD display - but you could go fancy with a small VGA screen or the like. The cheapest you'd get though still isn't free.

Jesper Ödemark [21010135]

David Clarke skrev:

Folks - in the Winter of 2006 I figured I'd look to see how much it'd cost to make a new version of the one-off ChromaKnob.

The idea was to simplify the electronics (do everything with a PIC) and put it all on a circuit board, to see if it was actually viable to perhaps build a few for folks. It would also have a larger display (4 lines vs. two) to show more information. I got a metal panel made, had a colour overlay for it, and got it up and running.

An overlay like that is what I'm planning for my Drehbank + cherry sides. I don't care about the rest of the limitations of the Doepfer unit. It works for me.

Thanks for sharing the pic!

Heinz Weierhorst [21010276]

Re: Knob Boxes

Hi all.

What's about touch switches? They can easy implemented on PCB level! Microchip and others offer such a product. See: http://www.microchip.com/mtouch

Randel Osborne [21030467]

David-

Thanks for taking the time to share your project and your thoughts.

My prototype at the moments simply spits out the appropriate CC data when an analog pot is turned, and I'm working to develop a display that will show the corresponding parameter and value. The user experience will be not unlike using a Moog Voyager.

With pots connected to fanned-out ribbon cable, the board size is small, and the spaghetti is not too bad, so far...

I, too display the routings, but use two 4P3T rotary switches to both generate a resistance for this value, and drive the display LED logic - kind of clunky!

At the moment, my project is simply a one-way path of data, from the knob box to the Chroma.

If I may ask, what is the nature of your bi-directional communication through the Chroma Port? Obviously, it would be great to read the values of parameters in the current patch, but the thought of displaying these in LED encoder rings would make this project very expensive indeed.

Do you think that there is any merit to trying to implement patch names, even if that data was written in the knob box itself?

Thanks.

Paul DeRocco [21030230]

Re: Knob Boxes

What's about touch switches? They can easy implemented on PCB level! Microchip and others offer such a product. See: http://www.microchip.com/mtouch

I get the feeling some people actually want to put their hands onto mechanical knobs or sliders. Personally, I don't think pots or sliders are a good idea, because they have the old problem of their visible position not matching the value of the parameter. Rotary encoders get around that problem, but don't show the current value. Motorized pots or sliders or LED readouts would be best, but you'd wind up with something more expensive than the Chroma was.

If one is going to design a panel that has touch controls that you can't actually feel, because they're just embedded in a flat surface, then I'd rather have a good sized touch screen tablet PC. Then, all you have to do is buy the device off-the-shelf and stick some software into it.

David Clarke [21030085++]

Re: Knob Boxes

... I don't think pots or sliders are a good idea, because they have the old problem of their visible position not matching the value of the parameter. Rotary encoders get around that problem, but don't show the current value...

A not-so-bad compromise is to use a rotary encoder but to have a small display that will indicate the parameter's value, where the 'starting' position is always the current value from the patch.

Another approach I considered was to have a strip of LCDs (or CRTs) with knobs around the edges. The idea would be that as you changed the patch the screen would dynamically change to a graphical representation of the patch structure, and provide labels for the nearby knobs. The actual values could then be shown too.

David Clarke [21030085++]

At the moment, my project is simply a one-way path of data, from the knob box to the Chroma.

If I may ask, what is the nature of your bi-directional communication > through the Chroma Port?...

If you're using MIDI (with a CC+), then the parameter values can be read with SYSEX ("Read program 0 parameter command", The Chroma CPU Plus (CC+): User's Guide - MIDI System Exclusive (SysEx)).

If you're using the Chroma Port itself, then you can use the "Read Parameter" opcode (Interface Manual: Command Descriptions).

For my Chroma Port implementation, I used a PIC 18F4320 and connected the Chroma bus (from the DB-25 connector) to it (with some terminating resistors and a D-flip flop).

Tom Moravansky [21030431]

Knob Box

After a sort of brief hiatus, I'm back on the list. Still have my Chroma w. the CC+ and am looking forward to the pressure sensor addition.

As far as the Chroma UI and knob boxes, here's some random thoughts on it. As an intellectual exercise, I created a Chroma CC+ template for the Novation Remote Zero controller. I was able to fit all the parameters on a single page. That's all well and good, but without an overlay showing exactly what is where, you kind of have to remember since it's mostly grouped logically, but not everything is exactly where you might think it should be. Using multiple pages might make it more intuitive.

One thing I noticed – there doesn't seem to be a way to send button push information for stuff on the left side of the panel. Things like selecting Edit A, Edit B, or Edit both A&B can't be done remotely (unless I missed something). The Novation will show you the name of the knob/slider and the value in the upper displays, but it's a compromise.

As far as designing a knob box from scratch, here's some things to consider:

Learn from the past – other synth designers needed to be able to display values with limited hardware and panel space. The solution used by the MemoryMoog (among others) was a simple display that showed the stored value on the left and the edited value on the right. Since you are only editing one parameter at a time from the panel, it was never a big limitation. So forget the multiple displays or the LED rings – a simply 4 character 7 segment LED display can serve the purpose. You can get fancy and have a 2 line display so you can show text in addition to the parameter number (saved and current).

Other thoughts – for some parameters (like patch and algorithm) you don't tend to be modifying them frequently or with large sweeps. You typically cycle through the options and then move on. I used a simple button press for those instead of a knob or slider. By repeatedly pressing the button, you toggle through the 8 or 16 options. Same for any parameter with a range of 0 to 3 or 0 to 7. You don't really need a knob or endless encoder for those, especially if you're displaying the value somewhere.

If you had the ability to select Edit A/B from the remote, you could dispense with the B parameters and just have indicator LEDs on the programmer to indicate whether you are editing A, B or both.

Jesper Ödemark [21010135]

Moravansky, Thomas M. skrev:

As far as designing a knob box from scratch, here's some things to consider: Other thoughts – for some parameters (like patch and algorithm) you don't tend to be modifying them frequently or with large sweeps. You typically cycle through the options and then move on. I used a simple button press for those instead of a knob or slider. By repeatedly pressing the button, you toggle through the 8 or 16 options. Same for any parameter with a range of 0 to 3 or 0 to 7. You don't really need a knob or endless encoder for those, especially if you're displaying the value somewhere.

...and here we come to the biggest flaw in the Chroma. Which moron decided that the resonance should have just eight steps? I'd like a word with him or her. ;) I want that on a knob even though it's just eight steps.

If you had the ability to select Edit A/B from the remote, you could dispense with the B parameters and just have indicator LEDs on the programmer to indicate whether you are editing A, B or both.

Not to go on nagging about the Drehbank, but I've set up identical sets of knobs on the two memories. One control A and one B. A click on a button and I'm in the other voice edit mode. It's simply great.

Just a little input too...

Paul Hackett-Evans [21010094]

I'd never call Phil Dodds such a thing, Jesper! His little friends in that big flying saucer will come and abduct you for saying such a thing!!!!!

However, I, too, would like more steps in the resonance parameter.

Perhaps David C could consider - Is this something that the CC+ software could be made to implement?????

Best Regards
Paul

(also loving the idea of a pressure sensor and a knob for every parameter)

Tom Moravansky [21030431]

My guess is that there were 3 bits available in the data structure for resonance and that's why it is only 0 through 7. If you make it 0 to 31 or 63, then you'll break compatibility with other Chromas and all other patches out there as well as Chroma Cult interfaces, and any software that talks to it.

Dave Manley [21030547]

Unfortunately no, this is a built-in feature of the voice card, as there are only 3-bits dedicated per channel for resonance. If you're willing to modify the voice card, I see there is an additional strobe STB3 available, which is a no-connect. You could piggy back an additional latch (or build a small circuit board) to provide more control outputs, which could be used to add additional resonance resolution. Of course, this would require firmware changes too.

Thomas Story [21030352]

Best controller box for Chroma?

I know there's great talk about designing a new knob box for the Chroma, but in the meantime, what are people using to control editing and live performance of the Chroma?

I'm thinking something from Novation (nocturn, XIO) the Korg Kontrol seems great for the price.

Something 200 and under, new or used would be great.

Suggestions?

Dave Bradley [16330135]

Re: Best controller box for Chroma?

I carried my chroma live for about 8 years, and found I could get the job done with 4 pedals, 2 levers, and a preprogrammed param slider.

Jesper Ödemark [21010135]

Re: Best controller box for Chroma?

I think you find all about this in the archives. But since I'm answering... Doepfer Drehbank is what I'm using.

Randel Osborne [21030467]

My Knob Box Update

FYI-

I've been through many revisions of the front panel graphics of the knob box that I am building for myself, and present the latest at:

I've taken some liberties with the nomenclature ( Filter instead of Cutoff, eg.), and the sequence of parameters from left to right in an attempt to make the interface more intuitive.

Upon the movement of a knob, the 2x16 LCD display will show the name of that parameter on the top line, and the value of the parameter on the bottom.

I have an 8 knob prototype built, and the immediate accessibility it provides dramatically changes the experience of playing the instrument - it's a whole new world!

I plan to have a 96-knob version complete in March, which I will photograph and videotape. If it functions as expected, I will explore the possibility of making a production run for interested parties.

Rob Vandivier [21030396]

Re: My Knob Box Update

Count me in, for 8 or 96!

Arun Majumdar [21030348]

Re: My Knob Box Update

Please count me in!!!

Ron Joseph [21030042+]

Re: My Knob Box Update

Count me in as well for the 96 knob version !

Mal Meehan [21010182++]

Re: My Knob Box Update

If it functions as well as your graphics suggest I'm in too for a 96 knobber!!

Tom Hughes [21030251+]

Re: My Knob Box Update

**Faints and falls out of chair**

Just so everyone knows, Randel came by my shop with the 8 knob prototype to try on my Chroma. Does it work? Absolutely!!! The experience of turning a knob on a control panel and hearing the filter change on my Chroma made my brain explode. I briefly considered wrestling the prototype away from him to keep, but he's bigger than I am.

Seriously though, that 8 knob prototype had me looking at the Chroma in a new way. I can only imagine what the final 96 knob version will be like (especially with the graphics and layout that Randel is proposing). Let me just say, everyone who gets this Chroma Nob better be prepared to take at least a week off of work when it arrives...

Frank McGing [21010198]

Re: My Knob Box Update

I can only imagine what the final 96 knob version will be like (especially with the graphics and layout that Randel is proposing). Let me just say, everyone who gets this Chroma Nob better be prepared to take at least a week off of work when it arrives...

Count me in! :-)

Dave Bradley [16330135]

Re: My Knob Box Update

Looks great, Randel.

Don't forget to relabel the second row for B params instead of A before you get your silkscreen cut!

Jesper Ödemark [21010135]

Re: My Knob Box Update

Very nice! Except I dislike the "NOB" typeface, but that might be just me liking the old school of the Chroma more...

I have an 8 knob prototype built, and the immediate accessibility it provides dramatically changes the experience of playing the instrument - it's a whole new world!

Amen!

I plan to have a 96-knob version complete in March, which I will photograph and videotape. If it functions as expected, I will explore the possibility of making a production run for interested parties.

Cool. We're looking forward to it. I'll gladly throw out my knob box if a dedicated one will have a decent pricetag.

Frank McGing [21010198]

Re: My Knob Box Update

Looks great, Randel.

Don't forget to relabel the second row for B params instead of A before you get your silkscreen cut!

...and I believe Set Split 21 should read "Attack threshold" :-)

Jeffrey D. McEachen

Re: My Knob Box Update

At 08:43 AM 12/22/2009 -0500, Randel Osborne wrote:

I've been through many revisions of the front panel graphics of the knob box that I am building for myself, and present the latest at:

http://www.redshift-consulting.com/nob/nob_3.4.gif

I've taken some liberties with the nomenclature ( Filter instead of Cutoff, eg.), and the sequence of parameters from left to right in an attempt to make the interface more intuitive.

That part's good. A few suggestions:

  • Why is it called Number 3 ("No 3")? Oh, I see, it's "NOB". The B looks WAY too much like a 3.
  • The Glide, Sweep, and Pitch on the bottom row should be "B", not "A".
  • The Patch diagram section needs a label to associate it with its knob. Perhaps "Patch Options"?
  • The Patch knob should be closer to the patch diagrams. I suggest putting it where the Kybd Alg is.
  • The LCD knob should be closer to the LCD. I suggest putting it where the Footswitch Mode knob is.
  • Putting the Footswitch & Keyboard knobs in the center will have the added benefit of centering the control knobs under the LCD.
  • If you're going to take liberties with the nomenclature, why not rename "Sweep" to "LFO" and "Wave" to "Oscillator",? The latter would better match the patch diagrams, which refer to "OSC", not "WAVE".
  • From the lack of buttons and the form factor, I gather this is meant to be a box that sits on top of the Chroma? If so, please please PLEASE consider reimagining it as a front panel replacement. I like sitting my Polaris on top of the Chroma, and I'm sure every Expander owner thinks that's the natural place to put their Expander.

Otherwise, it looks very good, with a logical layout. I look forward to seeing the finished product!

Rikard Latvala [21030448]

Re: My Knob Box Update

Hi,

Fantastic ! What will it cost ? Do I need to make a pre order ? And will it work on any chroma regardless of what extra boards are installed (CC+ or just original boards ) ? ..

Randel Osborne [21030467]

Re: My Knob Box Update

Rikard-

Thanks for the kind words.

I need to get one working to my satisfaction before I contemplate a manufacturing run. There is no need to pre-order, and I will provide more details in the new year. I have not yet done a cost estimate.

My box only spits out MIDI CC information, so the CC+ will be required for its use.

Randel Osborne [21030467]

Re: My Knob Box Update

Jeffery-

Thanks for the kind words and your suggestions - I'm going to try a few of the layout ideas. I'm still wrestling with the nomenclature, and I like your LFO and Oscillator ideas.

It is meant to be a box that sits either on top of the Chroma or the Expander, and the wood will match the aesthetics of both instruments. I don't think it is possible to adapt this design to replace the Chroma front panel - there is simply not enough room, and replacing the functionality of the panel would be an engineering challenge beyond my skills.

However, it could sit above the Polaris on a 3-tier stand.

Bruce Sklar [21030660]

Re: My Knob Box Update

I would definately want one if my Chroma responds to treatment and stops being fussy. Im fairly positive it will. I love the graphic btw.

Bruce Sklar [21030660]

Re: My Knob Box Update

Will this require a midi interface, or work with the existing 25 pin interface?

Andrew Dalebrook [21010180]

Re: Knob Boxes

@ Randel

I hate to be picky, but you seem to have some copy-paste errors, i.e. the bottom layer of most parameters is still A (instead of B). ;)

I have been working on a design myself. Please note, this is not a competition thing, just further discussion for the community.

My thinking was along the lines of making a cheap(er) controller that would sit above the top row of parameter buttons. This way patches could still be quickly accessed, and with all Set Split functions available. A larger box would sit on top of the Chroma, but what happens if your studio space is tight and you have another keyboard there? (Or if you do the unthinkable and gig your Chroma and have a Prog keyboard stack?)

Encoders seem more sensible to me, seeing as each parameter is quantised to a maximum of 127 steps. There could also be problems with scanning a large number of pots, where the jitter in the knob makes the position uncertain. And I'm not sure about using knobs for "switch" functions e.g. Wave Source (square, saw, pink, white).

Knob-per-function is nice, but _in my opinion_, nearly 100 is too many. I'm sure it would be okay once you got to know the layout, however the Chroma is such an extensive machine that too many knobs may serve as a hindrance. This might be a controversial opinion. Plus, each pot needs a covering knob and has to be wired into the circuit, which adds to the cost and time spent building.

My design involves thinking about the Chroma's parameter architecture:

Choose a Preset Choose your KB and footswitch mode and select output. These are the ones I'd probably use the least; I've left the last two off my panel. Choose your routing/"Patch" (series, parallel, sync'd, FM etc.) Do you want to edit A, B or both simultaneously? Edit important parameters with knob-per-function (filter, wave width etc.) Apply modulation. Some parameters have only limited mods (Sweep, ADR envelopes), whereas Pitch, Wave, Filter and Volume have more than one in a similar editing mode (i.e. Mod1 Select, Mod1 Depth, etc. for each of Pitch, Wave, Filter, Volume).

I've done a rough design. I only got Adobe CS yesterday, so sorry about the crappy power point/excel drawings.

The design uses a 4x20 LCD to indicate parameter names and values. I also had a go at trying to display the Patch routing on an LCD with text, arrows and "sync"/"ring" words which appear or not depending on the patch. The arrows could also flash ;-). A graphical LCD would be better, but I don't really know how to program them.

Moving along the panel are groups of parameters to edit. Some have a dedicated encoder, others have a switch which, when pressed, illuminates and modifies the knob to edit an alternative function. The "switch" parameters are cycled through with a button and have LED indication.

For the four parameters with multiple modulators, I've grouped them together. You choose which section you want to apply modulation to and then select a source and depth.

The plan is to use MIDIBox and get each encoder/button to send CC values to the CC+. The Core module is too wide, so would be mounted inside the Chroma with one or more DB-style connectors to attach the knob box. The shift register modules (digital out and digital in) are narrow enough to mount under the new panel. Power and MIDI connections would also be inside the Chroma.

Anyway, this is my take on the idea, so please feel free to comment. I'm happy to be alone on this, but any takers would need to have at least a slight interest in DIY :-)

Chris Smalt [21010280+]

Re: Best controller box for Chroma?

I carried my chroma live for about 8 years, and found I could get the job done with 4 pedals, 2 levers, and a preprogrammed param slider.

Amen to that, and if I recall correctly, using a pedal to modulate filter freq you get real continuous control as opposed to using the slider or midi, which is quantized in steps.

James Coplin [16330036+]

Re: My Knob Box Update

Also, you have both sections (sweep, filter, pitch, etc) labeled as "A" instead of "A" for the upper and "B" for the lower. And am I the only one who really hates "sweep"? Can't we just call it LFO?

Frank McGing [21010198]

Re: My Knob Box Update

And am I the only one who really hates "sweep"? Can't we just call it LFO?

I consider the rather oddly named 'sweep' to be part of the character and charm of the Chroma! I agree with changing 'cutoff' to 'filter' though - calling the entire filter section 'cutoff' never made any sense to me...

Bruce Sklar [21030660]

Re: My Knob Box Update

wow. some real controversy

I got my Chroma in 1983 or 4 while still in Boston. I went to town programming, went to take a couple of lessons with Mark Smith [2103-PT-002] up in Woburn about Chroma programming, and later found my patches that I gave to him working their way into the chroma cult sets... But I had no kids at that point. A Nob box would have saved me HUNDREDS of hours. And I used it live for 10 years, but it was the time spent programming it that made that possible. I also drove Steve Gromm and Bill Thomas crazy with questions as I bought the thing to join a band in VT, it was 2 years before I found a competent tech in Burlington.

So bring on the Box!!!

Chris Borman [21030194+]

Re: My Knob Box Update

I like the layout! Of course I have to add my 28c (inflation ya know). Love the patch markings with LED indicators! The markings by each knob are informative but can't be indicative. Other than motorized knobs, maybe backlight the markings? LED's are cheap. I would keep original nomenclature for continuity. Based on edit mode design, don't really need seperate A/B knobs. That saves 45 knobs, at least $300, 50% in the y dimension and dealing with edit mode here may be tricky. I love my Xpander, the minimalistic knob layout scheme is fine. If only that massive front panel was condensed a bit... (Checkout this form factor from an ebay ad - See attached). As mentionioned, size and form factor matters. Other than my babble, looks like your'e headed in the right direction. Great job so far Randel!

While I'm on a button roll, What about programming the CCplus to do something else with the cassette buttons? Anybody still use them?

Chris Smalt [21010280+]

Re: My Knob Box Update

I've been through many revisions of the front panel graphics of the knob box that I am building for myself, and present the latest at:

http://www.redshift-consulting.com/nob/nob_3.4.gif

I assume your idea is to have quick and easy access, in particular to parameters you would like to change while playing. These typically include glide rate, filter freq, lfo speed, attack and release times, detune, osc b tuning for ringmod patches. If I picture the knob box atop a Chroma, in your layout for sweep, the rate knob is close at hand. In the Control section however, the detune knob is surrounded by lesser used ones. How about moving it to the bottom line? Your layout for the filter section is very nice. From my perspective you have the envelopes laid out upside down: you want the AD(S)R knobs close, and the mod sources on the upper line. Likewise, glide rate should be under shape, and in the patch section, I'd prefer to have the tune knob on the lowest line (the middle one would be fine also).

If I understand right, you won't be using continuous encoders. For the knobs that select an option from a list, you chose to spread out the values over the full 240 degrees of rotation. For a list of 16, your knobs will rotate 15 degrees per option, for a list of 4, it's 60 degrees. I would prefer more consistency here, for instance a maximum of 30 degrees per option. It would be counterintuitive to have to twist a button really far, just because a list only has two or four options.

We all know how hard it is to read panel lettering in studio and stage lighting conditions. Even with the large size of the board, it seems to me that the lettering will be fairly small. It seems it would make sense to put the section names below the sections. With the board lying on top of the Chroma, they will be easier to read, and less likely to be blocked from view by your own hand or the knobs themselves. Ideally, for a panel that's meant to be used lying flat, the knob labels would be below the knobs too - I've looked at some knob boxes, and almost always your hand (and the knob itself) obscures the label when it's above the knob. With an instrument the size of the Chroma, you don't want to have to lean over its top panel to read a label.

I confess that I'm no fan of knob boxes - instead I feel the Chroma's one-slider approach is a lazy person's dream. Eyes on the display, left hand on the slider, and the right one dancing around selecting parameters. Rather than a knob for every function, I'd be interested in (OS X-) software that displays all parameter values at once, in nice huge numbers.

Paul DeRocco [21030230]

Re: My Knob Box Update

From: Frank McGing

I consider the rather oddly named 'sweep' to be part of the character and charm of the Chroma! I agree with changing 'cutoff' to 'filter' though - calling the entire filter section 'cutoff' never made any sense to me...

It's called that because that's the primary parameter of the block that gets modulated. Aside from LP/HP and Resonance, all the controls in that block are related to the filter cutoff. Similarly: Pitch instead of Oscillator, Wave Shape instead of Waveshaper, Volume instead of Amplifier.

Dave Bradley [16330135]

Re: My Knob Box Update

Makes total sense when you put it that way, Paul. Wish someone had explained that to me in 1983, but better late than never!

Frank McGing [21010198]

Re: My Knob Box Update

Dave Bradley wrote:

Makes total sense when you put it that way, Paul. Wish someone had explained that to me in 1983, but better late than never!

Yes indeed - thanks for the explanation, Paul!

Mark Smith [2103-PT-002]

Re: My Knob Box Update

I got my Chroma in 1983 or 4 while still in Boston. I went to town programming, went to take a couple of lessons with Mark Smith up in Woburn about Chroma programming, and later found my patches that I gave to him working their way into the chroma cult sets...

I gave a few lessons when the Chroma first came out but I never shared any patches with anyone.

Tom Moravansky [21030431]

Re: My Knob Box Update

Just some questions for all the people salivating over the mega-knob box:

Do you really need a dedicated knob for every function, or will a simple pushbutton do for some? Do you really need separate knobs for each modulation, or would a fairly comprehensive display combined with a 1/2/3 button and a single source and single amount knob work just as well? Do you really need dedicated knobs for functionality that will be modified maybe once or twice ever?

The reason for asking is that by reducing the knob count slightly, adding a good sized display, and being smart in what is dedicated and what is shared, a replacement for the front panel could be fitted. It would also save on cost since you don't need a dedicated power supply or case for it and the raw count of potentiometers and knobs would be lower.

Personally, I am having a difficult time finding a suitable location for my current programmers (PG-800, PG-1000, and Novation Remote Zero SL) and I have other gear stacked on top of my Chroma (in a keyboard stand) and have no interest in a huge box or a small box with lots of small lettering.

I always thought the issue with the Chroma was the lack of good display information. Getting the CC+ software updated to drive a 2x40 or 4x40 LCD display would get me 90% of the way there.

James Coplin [16330036+]

Re: My Knob Box Update

I agree. I would be fine with a push button to toggle between A and B sections. That alone would reduce a ton of the parts, therefore costs, and make it fit in the panel space. I also would love to see fewer knobs in exchange for led ring indicators of parameter values.

Randel Osborne [21030467]

Re: Knob Boxes

Andy-

Your design is a great approach, and I would encourage you to develop it further.

I appreciate all of the input that this discussion has generated.

My approach is clearly a "Brute Force" way of thinking, with the big layout and the many knobs, and that suits my needs and my engineering expertise.

I agree that a more elegant approach may be achieved by reducing the knob count, and incorporating a display that provides more information and/or through the use of rotary encoders with display rings.

I don't think that I know the instrument well enough to decide which parameters to eliminate from dedicated control, and I suspect that this decision may change from person to person.

Also, the knob box has allowed me to use the instrument in a new way for me - tracking the Chroma to a MIDI sequencer, then overdubbing knob tweaks. I'm hoping that having all parameters available as physical controllers will further enhance this experience, and may focus on a set of parameters seldom used for patch-making.

Thanks you all for the input.

Leonardo Ascarrunz [no serial number]

Re: Knob Boxes

How about motorized sliders instead of knobs for some of the most used parameters? That way the state of the machine is easily displayed when recalling patches.

Dave Bradley [16330135]

Re: Knob Boxes

I pity the original posters. I know how it is to invest a lot of time thinking and planning something, only to show it to a group and get inundated with a million conflicting requests.

Guys, I salute you. If you find any suggestions useful, by all means utilize them. Just don't get paralyzed trying to please everyone!

Paul DeRocco [21030230]

Re: Knob Boxes

From: Leonardo I Ascarrunz

How about motorized sliders instead of knobs for some of the most used parameters? That way the state of the machine is easily displayed when recalling patches.

Nice, but that'll quadruple the price.

Tom Moravansky [21030431]

Re: Knob Boxes

I pity the original posters. I know how it is to invest a lot of time thinking and planning something, only to show it to a group and get inundated with a million conflicting requests.

Guys, I salute you. If you find any suggestions useful, by all means utilize them. Just don't get paralyzed trying to please everyone!

I think you misunderstand – this is a particularly important topic to anyone that's invested time and energy creating patches on the Chroma. If you have 100 Chroma owners, you'll probably get 100 different takes on a knobby implementation.

You can certainly do it the way Randall proposed, which is similar to the original knob box that was designed which is similar to using a Dhrebank MIDI controller which is similar to any of a number of proposed solutions.

The devil is in the details and sometimes if you're so focused on your particular solution, you might overlook a better way to implement something. In addition to different esthetics, the practical issues of cost and ease of implementation come into play. It's all well and good to create something for yourself when time, money, and space are not objects, but if you propose a box that costs almost as much as a Chroma, then you might not get as many interested parties as you would with a different approach.

In addition, different people bring different skill levels to the table. Some folks are better at software/firmware design and others are more comfortable with a pure hardware approach.

Finally, there's the differing end goals – does it replace the front panel, sit on top of the Chroma, sit on a rolling stand next to the synth, or ??? Once again – ask a bunch of owners and you'll get a bunch of different answers.

The diversity of opinion should not dissuade anyone from pursuing a particular approach. Rather, it should be seen as additional input to be considered and then either incorporated or ignored as appropriate for their approach.

The people voicing their opinions are going to – continue using their approach, purchase a ready-built box if/when one becomes available, or pursue their own solution. None of which is invalid.

Leonardo Ascarrunz [no serial number]

Re: Knob Boxes

Nice, but [motorized sliders will] quadruple the price.

Alps 100mm motorized faders cost around 10 dollars in orders of 160+. Im not suggesting that all knobs get replaced, but the ones that make the most sense such as the ADSR controls.

Andrew Dalebrook [21010180]

Re: Knob Boxes

Thanks for the encouragement Randel, obviously it needs a bit more work on the design.

Re: Encoder LED rings, these are supported by MIDIBox too:

For my design, I might even consider butchering my Behringer BCR2000 for its encoders and rings. I calculate my design would need about 15 LED rings. That is not putting them on all the encoders, but only ones which have meaningful ranges (32, 64 or 128 steps. And resonance ;)). This would make the panel quite similar to the Moog Little Phatty, which has about four (from memory) pots with LED rings for each section (filter, envelope etc.). I hear these are very easy to tweak/program.

Another benefit of encoders is they can be detented or not, depending on the type of tactile response required.This would make selecting, respectively, non-continuous data (e.g. Mod Source) as well as continuous data (e.g Cutoff) possible.

I really do sound like the MIDIBox Cheerleader, don't I :)

I'm sorry if this is getting annoying, I just think it's a great platform for people, like me, who have an interest in DIY but not necessarily all of the design or programming skillz.

MIDIBox does motorfaders also.

Personally, I like knobs, and as far as visual feedback goes, LED rings + an LCD would be enough for me.

It gets a bit confusing when a knob/ring has to represent a few different parameters, though. It's all just a big weigh-up of cost, panel size and usability.

Andrew Dalebrook [21010180]

For those who obtained a christmas bonus or won the lottery, the JazzMutant Lemur might be up your alley.

It's a multi-touch LCD display running OSC and MIDI

Very pretty
Pretty expensive ;)

Rob Vandivier [21030396]

Re: Knob Boxes

I personally don't care if someone uses 8 or 96 knobs. anything will be an improvement over the pathetic user interface chromas come with. It was a cost cutting move to be sure and no one predicted the importance of hardware interfaces at the time. Cost will be a consideration, but ANY working design that isn't too dear would be worth considering as I don't have the time or knowledge to undertake this project in my short lifetime. Good luck. Hope that helps someone.

Chris Smalt [21010280+]

Re: Knob Boxes

I pity the original posters. I know how it is to invest a lot of time thinking and planning something, only to show it to a group and get inundated with a million conflicting requests.

Guys, I salute you.

That's how the original Chroma was developed. Worked out pretty well.

Paul DeRocco [21030230]

Re: Knob Controller

From: Andrew Dalebrook

For those who obtained a christmas bonus or won the lottery, the JazzMutant Lemur might be up your alley.

It's a multi-touch LCD display running OSC and MIDI

Very pretty
Pretty expensive ;)

Now that's the sort of thing that appeals to me, not a bunch of knobs. A scaled-down version of the Lemur, perhaps without multitouch, could be done on a much less expensive touchscreen PC, like an HP TouchSmart. For around $700, you get your Chroma controller, and it comes with a free PC.

Jack Colburne [21030142+]

Re: Knob Boxes

Well, I did my share of programming on that interface and also used the slider, pedals, and levers live and it served well.

The layout of the Chroma membrane switches always made enough sense to me (even if the terminology was a bit unique). Switching parameters became similar to reaching for a slider on another synth.. basically, it was where it expected it to be.

Picking a parameter and using the slider was not as unintuitive as it seems to be to many people. And it was many times easier to use and visualize than rack devices like the MKS-80 Super Jupiter (without the separate programmer) or the Kurzweil 2xxx series.

It was not as fun and personal as grabbing a set of knobs or sliders on a Prophet or Jupiter8, but "pathetic" isn't exactly the word i would choose.

And, the DX-7 did fairly well for itself (understatement intended..lol) with the same type of interface, but one that, to me, was more difficult to learn, understand, and program predictably.

All that being said. i would love and would have loved a hardware programming interface. But it was not as unusable, to me, as many people seem to feel.

Rob Vandivier [21030396]

Re: Knob Boxes

agreed, pathetic not the best word choice.. would anyone be offended by 'spartan'? Which, while not arguing the popularity of the DX7, I would also apply to the UI of that instrument as well. Anyone remember the DX7 knob box?

Jesper Ödemark [21010135]

Re: Knob Boxes

I finally had some time again to caress the old lady in the studio yesterday and would like to add: No matter which solution you chose to edit with knobs, find one. :D

It's amazing to just reach for the cutoff, the release, the modulation depth or whatever. I even managed to sequence some 303-ish bassline on the Chroma and that felt odd, but fun indeed!

Go to next message in thread, January 2010

Chroma Cult Patch Names

Tom Hughes [21030251+]

All this recent Chroma talk has had me up until 1AM the past two nights (and counting) playing my Chroma. I've been auditioning a bunch of the sound banks you can download from the Rhodes Chroma site. I saw there are patch names listed for the Factory Sets and a few of the others, but there doesn't appear to be any info or patch names for the Chroma Cult banks. Has any of this info turned up anywhere?

Chris Ryan [21030691]

That's one of the things I've listed on the Info Wanted page at the site.

Rhodes Chroma REV 14 & 3 on Ebay

Matrix [21030220]

[Item #320461954990]

Not mine. FYI, I have a post set to go up on MATRIXSYNTH at midnight tonight to capture it for historical purposes.

Dave Bradley [16330135]

And it fits Moog Arp Oberheim too!

Paul DeRocco [21030230]

Given that you can download the code from the Rhodes Chroma site and buy blank EPROMs for a few bucks on eBay, I pity the poor schmuck who falls for this.

But if this sale is successful, maybe I'll rip the chips out of my Chroma and two Expanders, sell them, replace them with others that don't have the "official" stickers on them, and go for a long weekend somewhere on the profits.

Doug Terrebonne [21030114]

Seriously this is an obscene rip-off. Matrix why do you promote such leeches like this?

Chris Ryan [21030691]

The last time these were for sale (see EPROMs on eBay, October) I contacted the seller to let them know that the price was too high, and they replied that "this is the third set that's been sold." However, they didn't sell in October and I have been following eBay auctions for a while but have never seen these at this price before; I doubt anyone is gullible enough to buy them for USD$295. I'm almost tempted to say, if they are, then they deserve what they get; it's very easy to find the Chroma site and information on the EPROMs.

Marais

Seriously this is an obscene rip-off. Matrix why do you promote such leeches like this?

Because he gets a piece of the pie from Ebay. Why do you think he is around here.

Chris Ryan [21030691]

Not sure this is entirely fair. Matrix does own a Chroma (21030220).

Matrix [21030220]

I do have a Chroma and that is why I'm on the list. That and I try to promote Chris' excellent site when new stuff comes in. I've been pretty diligent about that.

In the post I noted the link to the code on the Chroma site, so people would know. Take a look: MATRIXSYNTH: FENDER CHROMA Synthesizer EPROM Upgrade Set~REV 14 & 3. BTW, not everyone has an EPROM burner. I don't. If anyone out there does and would be willing to offer the service for less, let me know and I will update the post and put a new one up. If Chris is open to it, it would be great to have it on the Chroma EPROM page as well.

As for why I put the post up, I did so for a number of reasons.

  1. It's interesting that items like this are even for sale. The auction wasn't just a typical synth for sale, but parts for some obscure +/- 27 year old synth out there. Remember, not everyone out there is fortunate to have a Chroma like us.
  2. In a world of discrete vs. chip based and now DSP based synths, it tells people that might not know otherwise that the Chroma used chips and is OS based. The image and post tells quite a bit. It used multiple chips for the OS, not just one (I didn't know this), there are different revs of the OS, there is a separate OS for the Keyboard Scan vs. the synth itself (I didn't know this), and it's different than the Polaris. Obvious and even silly to some, but not for people new to synths and maybe even not to some famliar. Also, I post so much I find myself forgetting all of the little bits of synth info that has gone up over time, so even if I did know at one time, it's nice to be reminded and given the opportunity to reflect on what makes each synth unique.
  3. The post links to the Chroma site letting people know the OS is available and more importantly that there is this great resource where they can learn more about this great synth.

Think about it. Chromas are part of our world, but for others it's just some obscure synth out there. A lot of people that come to the site probably don't even know what a Chroma is. They won't even think about it unless they are reminded. The post does this. It also lets them reflect on what components synths use to work. However brief this reflection may be it is acknowledged. All of this is interesting and worth posting in my opinion.

As for a cut on the auction, I didn't post the affiliate link to this list and my time would be better spent posting synths that would sell on the site, so that was not the reason. I put 30 to 50 posts up every single day, so the bar actually is pretty high and Chroma EPROMs would not go up to make a buck considering. The site is meant to be a look back in time, twenty, thirty or more years from now. The auction posts that go up not only captures images and interesting historical bits, but they let people know what was being sold. Will there be a day where certain items are no longer listed? I'm also adding BINs to auction posts, so we'll also be able to see what things were sold for in time. To not post affiliate links for auction posts that go up would be pretty idiotic on my part. It doesn't cost the seller or buyer anything, so it is relatively transparent. It only costs Ebay. I put a lot of time into the site and I post what people send in so although I enjoy it, there is work put into it.

Arun Majumdar [21030348]

Good job Matrix!!!

Peter Forrest [21010096]

Seconded.

Mal Meehan [21010182++]

It's people like Chris and Matrix... and Peter (and a few others), that keep us all up-to-date in the knowledge of yesteryear synths.

Without the Herculean effort of these people, I know personally that I wouldn't know what I know now... Although I am temporary without a Chroma at the moment, Chris' website has been a tome of reference for me over the last 5 years, helping me rebuild and programme my 3 Chromas... and Peter's Auctions have bought me directly a Chroma, and a few other synths over the years... and we can't forget those wonderful reference books... they make great reading while on the thrown! And lastly, Matrix and his synth blog... a treasure trove to all us synth heads... it's the only blog I visit everyday... dare I say it but it's wonderful primary colors and it's little teeny-tiny videos of hard to find, ageing vintage synths is frankly like porn - well done to you all.

Doug Terrebonne [21030114]

Some of us see a big difference between what Chris has done building his wonderful Chroma site and what people like Matrix do which is mostly re-post other people content on a blog full of ads and ebay affiliate links to make money...

Mal Meehan [21010182++]

Well that's fine... each to their own.

I wasn't grading the worth of each site against each other, they all have their value.

As a web designer of more then 15 years, given how long it takes to put a blog together I personally don't have an issue with someone making some money out of their time spent designing, building, maintaining and uploading if it means the site is going to stay up... and for those people out there that don't know, there's very little money to be made in such ventures.

I like going to the one blog and getting my fix in one hit - I value my time so thanks again Matrix... your time and effort is valued here.

Arun Majumdar [21030348]

I review Matrix daily because he provides a one-stop shop of references and connects the dots for me in a way that I enjoy since I have neither the time nor inclination to search for. It's a valuable service.

Matrix [21030220]

It's a blog Doug: Top 10 Tips for New Bloggers From Original Blogger Jorn Barger.

And it's a lot of work. It takes anywhere from three to six hours a day, seven days a week. Vacations included. I haven't missed a day in a couple of years now. I not only post what I come across but what others send in, and people send quite a bit in. I currently sub to 406 RSS feeds, a huge number of YouTube feeds, VIMEO and as you know I'm on various lists. I've been around for a while. I think Mal and galaxiesmerge got it spot on. It would take forever to find all of this stuff otherwise. I originally created the site for me for that exact reason. It was impossible for me to track things otherwise.

BTW, a good amount of stuff that comes in comes directly from people that want to share what they are doing but don't have an audience yet. I'm guessing the majority of the readers, myself included, that visit the site would miss out if the site wasn't where it is today. I get over half a million pageviews a month now and it feels good using that to promote people, events, organizations and small manufacturers.

Note, I started the old MATRIXSYNTH site in Oct of '97. It was a crappy old link list as you can see and simply didn't scale, hence the blog.

BTW, no one has to pay for the site and no one has to click on the ads. No one should click on the ads unless they are actually interested in the ad itself, because that would be a rip off to small businesses trying to promote themselves, and that is not cool in my book. As for any ad revenue I do make, that is private. Sharing that would demean me and the site and it is obviously no one's business. It may be a little, it may be a lot and it is always relative to time spent and earning potential elsewhere. Even if I was running the site soley for money, it wouldn't change what the site is, independent of me. The one thing I am glad about is I kept the site about synths and not me. People use the site for their own reasons.

Chris, apologies for dragging this on.

Jeffrey D. McEachin [21030073+]

Some of us see a big difference between what Chris has done building his wonderful Chroma site and what people like Matrix do which is mostly re-post other people content on a blog full of ads and ebay affiliate links to make money...

Some of us see big increases in traffic when Matrixsynth posts a link to our website and very much appreciate it. Matrixsynth is probably THE #1 news/link aggregator for synths, and covers a lot of small websites (like the Chroma site and Synthcom) that get missed by others. It's obviously a LOT of work, and I think Matrix deserves every penny those ads bring in. If you think otherwise, then you have something in common with Rupert Murdoch involving the relative locations of your head & ass. ;)

Peter Forrest [21010096]

I don't think there's any doubt that Chris's site stands head and shoulders above any other single synth world contribution, for a number of reasons, one of which is the way he seems fantastically immune to seeking even a tiny financial reward for all his work.

Jesper Ödemark [21010135]

The Chroma site is amazing... and I hope it can keep running on blood, sweat and tears and the occasional donations from us users.

Some other synth sites even promote skiing resorts... or so I've heard. ;) (It's a joke Peter!)

Chris Ryan [21030691]

I don't want the tone to deteriorate here. The list has been pretty much completely free of accusations and flames for over a decade.

From my perspective, Matrix has put in a tonne of work on his blog—more than I have on the Chroma site, as it's a constant daily grind. I'm not sure how he does it. matrixsynth.blogspot.com has been a source of quality visits to rhodeschroma.com (an average of four page views per visit over the last three and a half years), and in the past year has been the fourth highest source overall, trailing only Google Images, Wikipedia, and the Rhodes Super Site. See Site Statistics for more information.

Donations have kept the Chroma site going in terms of real financial outlay the last few years. There are other rewards in running the site, for instance learning about web technologies, hearing from cool people from all over the world, and of course providing support for what I think is a worthy instrument. And I believe we get back from the web what we put into it; if people didn't make the effort, there wouldn't be much content out there.

Affiliate links seem to me to be a way to generate revenue while staying on topic. At least that's what Matrix seems to do on his blog. Anyone can, of course, disagree, and they're free to avoid any such site.

I'm encouraging Matrix to continue to post here. He has a broad set of sources for up to date activity surrounding the Chroma (and all synths), and I've never seen a post from him that differs from what the rest of us contribute in terms of subject matter or value.

I'm proposing we move back on topic at this point.

David Gowin [21030611]

And now for something completely different. A man with three buttocks. (For the Monty Python fans)

Peter Forrest [21010096]

Thanks, Chris.

And it looks like 2010 might be the best year yet for the Chroma to reach its full potential as simply one of the most complete and powerful synths ever made!

Let's hope so.

bubinga chroma and expander

Dave Bradley [16330135]

Found this browsing gearslutz - looks beautiful but heavy!

Ron Joseph [21030042+]

Beautiful :)

Tom Hughes [21030251+]

Yup, those are mine! I know who took the pic, but I wasn't expecting it would be posted on a forum. I would have gotten some sexier shots of it myself, I'm not sure that photo quite does justice to the finish. But yeah, those are my Chromas :-)

which psu kit should I follow?

Michael Salmon [21030155]

hi all,

im a bit confused between these two different set of instructions? not sure why one is under "Upgrades" and another under "Projects"?

Chris Ryan [21030691]

The first is a kit available for purchase; the second is more of a DIY project for which you have to go out and find an SPSU that meets certain criteria.

I've been thinking of shuffling the site around a bit so that the pages classified as "Upgrades" within the current Tech section, which comprises upgrade kits made available by list members, are part of a new section of the site that would also incorporate the information in the current MIDI section. Perhaps this would lessen the confusion.

Update on Site Expenses and Donations

Chris Ryan [21030691]

Back in the fall of 2005 I set up a PayPal donation system for the site. A couple of times since then (April 2007, January 2009) I've posted updates on how the fund was doing. The response this year has been very strong, and a couple of recent generous donations prompted me to realize that I have what could be considered a surplus. At the current rate charged by my ISP, there are probably enough donations to keep the site going until about 2020! I would like to decide how to handle this; individual contributors may have their own preferences and are free to contact me. Some of the options I can think of:

  1. Continue to reserve the money strictly to cover hosting costs. This is how the fund was originally advertised, and without overwhelming support for doing something else I have a strong inclination to keep it this way. I'll maintain the site even if I run out of funds from donations, but at this point I wouldn't have to worry about that for about a decade.
  2. Put some of the money towards software used to create and maintain the site. For instance, BBEdit (I already own it, but there are occasional paid upgrades); Acorn (cheaper alternative to Photoshop, which I use now and is mostly overkill and way overpriced); Cornerstone (I've got this far without version control but really should be using it—the site comprises over 2300 files); Interarchy which I've used from the beginning for synchronizing my working copy with the live site via ftp (again, upgrades).
  3. Small honorarium to a visual designer for some work on the site. I've never felt that it was quite finished in this respect, and it would be good to get some professional input and another set of eyes; I have several colleagues I could ask and work with locally.
  4. Funds for obtaining relevant materials for the site (such as magazine articles on the Chroma) from eBay and other sources; and other material costs. (I have in the past used some of the donation fund for large format scans of the schematics etc.)
  5. Compensation for time and effort spent maintaining the site. (Perhaps even, as one of the recent donors suggested, "a bottle of wine to help the formatting of the next article go that much smoother"!)
  6. Profit. This would likely end up being essentially the same as #2 and/or #5, but I might put something towards the Chroma software for Mac OS X I've been threatening to do for years.
  7. Other ideas?

These options are, of course, not mutually exclusive.

Also, I could continue to solicit donations, or pull the donations page for now. If I keep receiving donations, and continue exclusively with option #1, at some point I may have to set up a trust fund and put the whole thing in my will so that any grandchildren I have can keep the site hosted somewhere. :)

And just to put everything on the table, initially I presented text ads as an option. I hesitated to bring this up, given the recent discussions about a certain blog. I prefer an ad-free site, but I don't think relevant ads are necessarily evil. One issue here is that the site only gets about 70-90 visitors a day, so it might not be viable.

Input, please.

Luca Sasdelli [21010226]

Hi Chris,

please remember that I can host your site for free on a 100Mbps symmetric connection.

Peter Forrest [21010096]

All those suggestions look fine to me. Buying software especially looks logical - but the choice of what to do should be entirely up to you.

The possible danger with having ads is that it attracts people who have a one-off thing to sell but no special interest in Chromas. They think that here is a free way of getting to a captive audience who will pay high prices. (I think that's true, because I have to say I've done the same once or twice on specialist sites where I've wanted to sell something I dont know or care a lot about, and registered purely to put the ad up.)

We might get some more $500 rusty pedals, for instance.

Ron Joseph [21030042+]

Chris,

Do as you see fit; you've done a great job so far.

Chris Ryan [21030691]

On 2009-12-17, at 1:25 AM, Luca Sasdelli wrote:

please remember that I can host your site for free on a 100Mbps symmetric connection.

Thanks, Luca. I tend to have a bias towards using a commercial provider, for a few reasons. There's always technical support available; paying the (low) monthly fee makes it a commercial transaction to which one has recourse if things go south. My experience with the mailing list, having had to scramble to move it several times over the years, also makes me slightly wary of depending on friends. Finally, I like supporting a local hosting company. All that said, I'll certainly keep it in mind; but the issue remains, how to allocate the funds donated—which, if they weren't going to hosting fees, would be more substantial.

Bruce Sklar [21030660]

Boy, Chroma software for OSX... then I could teach synthesis to my high school tech classes with a Chroma, and I could use the ARP 2600 manual for a textbook fairly easily !! Im hoping of course, that a good cleaning will allow my Chroma to tune up and then NOT go blank as it's currently doing as soon as I hit 3 or 4 notes.

Arun Majumdar [21030348]

Hi Chris,

I am happy to contribute for your time as well. I am interested in Mac OS X software too! In fact, I will send a contribution via PayPal this Monday in time for the Holidays :)

Mark Smith [2103-PT-002]

Do number 2, I love buying tools!

Jesper Ödemark [21010135]

My choice would be one or more of these:

3. Small honorarium to a visual designer for some work on the site.
4. Funds for obtaining relevant materials for the site
5½. "a bottle of wine to help the formatting of the next article go that much smoother"!

I love the work you put in Chris, but profit is a hard thing. You'll never get back cash for the time you put in and you'll be sitting on more than one chair etc.

Not forgetting:

8. I may have to set up a trust fund and put the whole thing in my will so that any grandchildren I have can keep the site hosted somewhere. :)

Which isn't a bad idea and a very cool legacy for the coming generations. :D

Donald Tillman

Chris,

Here's a crazy idea: Pay yourself a bonus.

(Heh-heh; political flamewar in 4, 3, 2...)

Eric Inglebert [21030075]

Finance (part of) a project development like a Chroma knob box:

  • launch the project
  • select the best designer / project
  • finance the development (zero interest loan ?)
  • get money back

Werner Schöenenberger [21010114]

Hi Chris,

IMHO you did so much for the Chroma community that I think you should be free to use the donations in a way you want. The idea with the bottle of wine is not bad so (c:

Dave Bradley [16330135]

Finance (part of) a project development like a Chroma knob box:

  • launch the project
  • select the best designer / project
  • finance the development (zero interest loan ?)
  • get money back

Oooh! Group financed R&D - I love it!

Matt Thomas [21010021]

I agree with most people so far - you should do whatever you see fit, I didn't donate with pre-conditions :)

My opinion fwiw is that you could buy another 5 or 10 years of hosting, put any remaining balance aside towards future software updates and then the site's financial future is assured. That done why not start a new donation scheme towards whatever of the various remaining options you see fit?

I think the site looks superb btw, very in keeping with the Chroma's own very simple and clear layout, so I'd vote for buying Chroma ephemera/developing OSX software/establishing a wine cellar.

Matrix [21030220]

Ditto. Chris, PLEASE buy yourself a bottle of wine or two with my donation. :) You put a lot of hard work on the site and deserve a little something back in my opinion. Only you know the time you put in and how much that would translate into if you spent your resources elsewhere. I would do whatever makes maintenance and upkeep of the site easier for you. Personally I think 2020 covers keeping the site live for now, and if 2020 comes around and you need more help, I'd be happy to help. Also, I wouldn't take the donations link down. I think you give me and others more than what we give back via any donation, so anything extra is all yours when it comes to mine. I usually think of donation links as appreciation links.

Chris Smalt [21010280+]

I might put something towards the Chroma software for Mac OS X I've been threatening to do for years.

The Chroma site works for everyone, Mac, PC, Un*x. You don't even need a Chroma. Mac OS X software only works for Mac users (I'm one). It would be good to see this as a separate project. People interested (me, me, me!) could finance that research on an individual base through Paypal.

Chris Ryan [21030691]

Yes, I would probably release this as shareware, separate from the site. I don't know why I mentioned it in the site expenses discussion; there's really no financial overhead for development, as I have good hardware (a Mac Pro), already have a few books (Hillegass, Kochan, etc.), the Apple developer tools are free, and at least initially I probably wouldn't need a paid ADC membership.

I'm thinking I might make this a priority for 2010; I've wanted to do it for years, and the recent enthusiasm for knob boxes indicates that there could be some demand for what is essentially a "software knob box." Even if there were only a handful of users, it would be another step into the 21st century for the Chroma.

Chris Smalt [21010280+]

As I mentioned in the other thread, my main interest is a large display of parameters, preferably with automatic enlargement of the value that's being edited. Cf. the iPhone keyboard, where the key you tap is displayed huge. I see no use for fancy graphs - I grew up on early PPG synths and the Chroma, and visualizing the numbers has become second nature to me.

In most current software, I think the graphs are too large and the numbers too tiny. Typing them in often works in a clumsy way, and I think having to use a mouse just to increase or decrease a value by a couple of units is silly. A keyboard shortcut would be most welcome here, the simpler the better. I'd very much like to be able to jump from one parameter to the next with the arrow buttons, and jump from section to section with something like Command-arrow, in order to avoid having to use the mouse all the time.

I hope it will work in Tiger - I'm on a Powerbook from 2005.

Chris Ryan [21030691]

Re: Mac OS X Chroma Software

On 2009-12-23, at 7:24 PM, Christian Smalt wrote:

As I mentioned in the other thread, my main interest is a large display of parameters, preferably with automatic enlargement of the value that's being edited. Cf. the iPhone keyboard, where the key you tap is displayed huge. I see no use for fancy graphs - I grew up on early PPG synths and the Chroma, and visualizing the numbers has become second nature to me.

In most current software, I think the graphs are too large and the numbers too tiny. Typing them in often works in a clumsy way, and I think having to use a mouse just to increase or decrease a value by a couple of units is silly. A keyboard shortcut would be most welcome here, the simpler the better. I'd very much like to be able to jump from one parameter to the next with the arrow buttons, and jump from section to section with something like Command-arrow, in order to avoid having to use the mouse all the time.

Interesting ideas. I tend to agree. I remember struggling with the Galaxy editors (though Opcode only ever included librarian support for the Chroma).

I hope it will work in Tiger - I'm on a Powerbook from 2005.

Unfortunately, the chances of this are slim to none. I've been working in Objective-C 2.0, which is Leopard (10.5) and Snow Leopard (10.6) only. The benefits, such as garbage collection, are just too significant.

Chris Smalt [21010280+]

Re: Mac OS X Chroma Software

OK OK, I'll get a MacBook Pro already :-)

Dave Manley [21030547]

silly. A keyboard shortcut would be most welcome here, the simpler the better. I'd very much like to be able to jump from one parameter to the next with the arrow buttons, and jump from section to section with something like Command-arrow, in order to avoid having to use the mouse all the time.

As a long time mouse hater :-) , I heartily endorse the use of well planned keyboard shortcuts.

Chris Ryan [21030691]

Re: Mac OS X Chroma Software

On 2009-12-24, at 8:43 AM, Christian Smalt wrote:

OK OK, I'll get a MacBook Pro already :-)

You should be able to run Leopard on your PowerBook: see Requirements for Mac OS X v10.5.

But a MacBook Pro would be nice! That's my work machine.

Re: Mac OS X Chroma Software

Chris Smalt [21010280+]

I know, but will it be faster than Tiger? My PB is from the generation developed with 10.3, but came with 10.4 pre-installed and was sluggish right out of the box, so I ran 10.3.9 for as long as I could, compatibilitywise, and it worked fast and flawlessly. I had to switch to 10.4 two years ago, but it never felt right, and there are a number of unsolved crash mysteries that pop up at regular intervals. This happens on all 12 inch 1.5 GHz Powerbooks that I know, btw - it's not related to a specific machine. So I'm not thrilled by the idea of having to go through another round of installing a system and testing all my apps.

Chris Ryan [21030691]

Re: Mac OS X Chroma Software

Chances are, these problems are fixed in 10.5. I've found each release since 10.0 to be faster and more stable on all my computers—and I run a number of Macs, from my own home and work computers to my wife's, daughter's, dad's, and some old machines (not to mention being unofficial Mac sysadmin at most of the jobs I've had since the 1980s). I've recently installed 10.5 on our old 15-inch PowerBook G4, and while I'm only using it to share an ancient laser printer, I haven't seen any glitches.

Chris Smalt [21010280+]

As a long time mouse hater :-) , I heartily endorse the use of well planned keyboard shortcuts.

I can't say I hate the mouse, but patch editing mostly comes down to touchups: +1 here, -2 there, and that's so tedious with the mouse.

Chris Smalt [21010280+]

Re: Mac OS X Chroma Software

I wish I could say the same... 10.3.9 was my fave for this Powerbook.

Dave Blees [21030552]

Re: Mac OS X Chroma Software

Chris - These days I, too, am a Mac OS-X user (10.6), and unfortunately have not yet come across a better graphical editor adapted for the Chroma than my ancient AtariST GenEdit version, which at least had graphical envelopes and such. (IMHO, of course!)

I think the Cubase edit panel is pretty lame - a low-effort stab at it, I'm sure. I'd rather use a slider and 50 buttons.

If you are indeed developing some type of OS-X editor, I'd be curious to know if it'll be based upon some existing 'generic' editor platform, of if you're planning to roll a whole new approach totally customed for the Chroma. Of course, if you get a great Chroma editor happening for OS-X, you could probably make an iPhone app out of it as well.... ;-)

Chris Ryan [21030691]

Re: Mac OS X Chroma Software

On 2009-12-24, at 6:07 PM, D'Ett'n'Dave wrote:

Chris - These days I, too, am a Mac OS-X user (10.6), and unfortunately have not yet come across a better graphical editor adapted for the Chroma than my ancient AtariST GenEdit version, which at least had graphical envelopes and such. (IMHO, of course!)

I think the Cubase edit panel is pretty lame - a low-effort stab at it, I'm sure. I'd rather use a slider and 50 buttons.

I agree. The Cubase editor interface is an example of the "universal" editor problem. Many publishers attempted to support virtually every keyboard produced, going back at least to the emergence of MIDI-capable keyboards in the early 1980s; provided some form of toolkit for end users or at least third-party developers (perhaps partly in an attempt to get help in achieving near-total instrument coverage); and were cross-platform (Mac OS and Windows).

The net result of this ambitious program was diluted quality: instrument support was wide but shallow, and the end user experience was compromised. Most of the patch editors consisted of laundry lists of simple sliders and buttons, organized by function or component but rarely representing the instruments' architecture or strengths in more than a superficial way—or taking account of their individuality and quirks. The third party programming capabilities, along with cross-platform support, further limited the ability to take advantage of advances in user interface technology on either Mac or Windows.

This was all quite self-defeating, as the original goal of the products was to provide a user interface superior to that offered by the instruments themselves. Whether or not there was a marginal net success in this respect seems to have been overshadowed by the fact that the user experience was poor in comparison with other software—in particular when compared with sophisticated MIDI sequencing and audio recording packages. As a result, the category has all but disappeared.

If you are indeed developing some type of OS-X editor, I'd be curious to know if it'll be based upon some existing 'generic' editor platform, of if you're planning to roll a whole new approach totally customed for the Chroma.

You'll probably guess, from reading the above, that I'd be going with the latter approach.

Of course, if you get a great Chroma editor happening for OS-X, you could probably make an iPhone app out of it as well.... ;-)

I don't think Core MIDI is available as part of iPhone OS, so unless the iPhone app communicated wirelessly with the desktop app, you'd be out of luck. But would anyone really want to program their Chroma with their iPhone or iPod touch?

Merry Chroma everyone!

Jesper Ödemark [21010135]

A very geekish shot from the studio, the 24th of December 2009:

Tom Klepacki [21030025]

Wasn't that the inspiration for the song by 'America'? "Oh, Oz never gave... a Chroma... to the Tin Man... That he really... didn't already have..."

Have a good holiday, all.

Re: Pressure Sensor and Rhodes Chroma CPU Plus (CC+)

Go to first message in thread, October 2009

David Clarke [21030085++]

Following up to an earlier post on the Chroma List, the transmission of Polyphonic Pressure commands via MIDI has been added to the CC+ firmware: Revision 213 (December 2009).

Chris Borman [21030194+]

That's great news. Thanks David! A CPU Plus is next on my list!

Progress update on the Chroma Pressure Sensor - Parts on order, Jan 15th is due date for the actual Sensor from Sensitronics. I will need another week to build up a kit, validate the install and test the keyboard response/feel and update documentation.

Peter Forrest [21010096]

If only all commercial makers were as responsive and efficient with upgrades.... Thanks!

Jesper Ödemark [21010135]

You guys are the best! It feels like a christmas present even though I have no pressure sensor yet... What a fabulous product support the CC+ have. :D

Luca Sasdelli [21010226]

Excellent! I've just ordered a new Eprom for this :-)

Frank McGing [21010198]

Superb! Thanks David! :-)

Frank McGing [21010198]

Progress update on the Chroma Pressure Sensor - Parts on order, Jan 15th is due date for the actual Sensor from Sensitronics. I will need another week to build up a kit, validate the install and test the keyboard response/feel and update documentation.

Great work Chris - really looking forward to it!

And a happy new year to all! :-)