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ChromaTalk Archives: August 2006

Re: Greetings and Chroma editor questions!

Go to first message in thread, July 2007

Rob Belcher [16330123]

Hi Chris,

Oh that sounds great- shame im PC based though!

It would be great to have an PC Editor for the Chroma like the Waldorf Pulse editor that opens up inside Cubase (like a VSTi UI) that you could tweak and control all the Chroma parameters on the screen... Surely one of you software guys could knock this up?? :)

Jim Russo [21030433]

So you would have to have Logic Audio on the Mac as a host for the AU version of the editor Chris ?

Thats a bummer ? I have a mac, but have gone back to hardware sequencing on a MPC60II for making music. I would like to try the editor one day, but if i have to buy Logic (isnt the full version like $800 now ?) I would have to pass. Now if it would run as a VST plugin in say Mackie Traction2 ($200?) I might be more up for that or as a independent program ?

Uro [21030401]

Give Chris a break and get a Mac. When are you going to use a Mac for music... you can still use Cubase SX/SL.

David Gowin [21030611]

Nothing personal, no offense intended, but I've already made my investments in PC Hardware and software and can't afford that extra thousand or so for a Mac, and then the few hundred or so additional for Mac music software...

Chris Ryan [21030691]

So you would have to have Logic Audio on the Mac as a host for the AU version of the editor Chris ?

No. There are lots of apps that support Audio Units, including Ableton Live, BIAS Peak, GarageBand, and probably a host of others. There may be Windows apps as well--perhaps the Windows versions of Live and BIAS Peak, I'm not sure. Anyone know?

Service Manual

Chris Ryan [21030691]

The entire Service Manual (1983 Rhodes edition) is now available on the site, complete with large format schematics and drawings in PDF format.

Thanks to David Clarke [21030085++] for advice and for reviewing the content, as well as providing the equation graphics for the Circuit Descriptions page.

As this was a significant effort--25,000 words manually transcribed and a pro scanning job on the schematics--I may consider this update a "special summer double issue" so I can devote more time to some other projects, including the Chroma software for Mac OS X I've been working on.

Uro [21030401]

What a great job: congratulations!

David Clarke [21030085++]

The entire Service Manual (1983 Rhodes edition) is now available on the site, complete with large format schematics and drawings in PDF format.

A personal word of thanks to Chris for this.

While there have been scans of the material on-line, it is difficult to quickly find data in a scan (especially when you need to wait for the large files to download over a low-speed internet connection).

It is also quite a treat to finally get the circuit board layouts in colour (so you can easily see what traces are on the solder side/circuit side, etc. - vs. the strict black-and-white copies you'd often get with the hardcopies floating around).

Stack switch repair

Tom Moravansky [21030431]

After a long silence, I finally got around to cleaning up my battery-acid damaged Chroma. As a side note - if you're looking to buy a Chroma and someone has one "that's been sitting in its case for the last few years' - run away. A Chroma standing upright (keys up) suffers the most damage when a battery leaks. My Chroma had damage to: the CPU board (extensive), 2 stack switches, the right stack switch PCB (minor), channel motherboard (minor), and a voice card (extensive). As of now, the new CC+ board is installed and everything is repaired except the voice card (waiting on some ICs).

Stack switches. They can be cleaned/repaired. My symptoms of acid damage were: sticking sustain - a note would sustain forever, and kill all voices - playing a note would shut down all voice generation until a reboot. Examining the stack switches revealed the obvious - corrosion was causing problems.

Here's what I did to get them back to 100%.

Remove all voice cards. Unhook the ribbon cable between the right and left stack switch PCBs. Unhook the ribbon cable from the front panel board. Loosen the 3 screws holding the right stack switch assembly to the Chroma (screws are behind and underneath the PCB).

Take out the stack switch PCB. Tape a block of foam onto the pins from the front panel ribbon cable (yes they will catch on something and/or get bent if you don't do this). Use a solder sucker or desoldering iron and completely clean out the 3 contacts on every stack switch you need to repair. Next, flip the switch assembly upside down. Using a 5/32 drill bit (use an old regular tip - not a pointed 'bullet' type bit), using medium speed and pressure, carefully drill out the bottom of the post holding the stack switch to the metal frame. Just drill enough until the rim breaks away - you shouldn't have to go far into the aluminum frame at all. At this point, if the contacts are unsoldered, you should be able to wiggle the stack switch up and down to get it out of the frame.

Set out a white sheet of paper or cloth. Using a thin screwdriver, carefully take apart the stack switch section by section. Lay the parts down on the paper in the exact order of disassembly. The good news is that you have 5 octaves of examples even if you do move things around. Those 2 black posts can/do come out. Try to be careful not to bend the metal tines during disassembly.

Based on research I did, white vinegar is supposed to neutralize alkaline and NiCd battery acid. If someone has had better luck with some other chemical, please let us know. I washed each metal and fiber part in vinegar then carefully sanded off the corrosion. Once it was sanded clean, I re-washed it and dried it off. After all parts were cleaned, I reassembled the switch. Pay attention to the curve of the tines and make sure they are making contact like the other switch assemblies. Also carefully look over the PCB area where the stack switches are soldered and clean that area thoroughly.

If you have access to a pop rivet tool and rivets, use a 1/8" (3mm) long aluminum rivet. I put the head of the rivet on the top of the stack switch to match the look of the rest of them. Make sure all the parts of the stack are aligned and as straight as possible (and the contacts are well seated in the holes in the PCB) before squeezing down on the rivet tool. After riveting, solder the contacts and reassemble the whole deal.

It took me about an hour to do 2 switches, mainly because of the extensive corrosion and the scrambling around in my tool area looking for my rivet tool and rivets. If anyone needs them, I'd be happy to ship the tool and rivets. Just pay the cost of postage both ways and I'll send it out.

Hope that helps someone.

Mailing List Problems

Chris Ryan [21030691]

There were some problems with the mailing list through much of July; many subscribers were not receiving messages. Although the server administrator could not determine why messages were being rejected for some, it appears that the problem has sorted itself out.

Jesper Ödemark [21010135]

I checked the archive and I _did_ receive everything but apparently the mail server said I didn't... Just FYI...

Chris Ryan [21030691]

I don't quite understand. You mean they were in your in box already read? It may help us troubleshoot the problem to know. Could you send a copy of one of these messages, including headers, to me?

CC+ Plus owners, how you liking your update ?

Jim Russo [21030433]

A vacation got in the way of us getting on the first batch of CC+ plus boards and we wait patiently for the next batch. How is everyone liking there's ? Chroma running cooler ? less MIDI lag ?, other things? Did you get he Midi interface option or are you using your syntech/cult/face still? and how do you like patch bank 3 ? : )

Jesper Ödemark [21010135]

A vacation got in the way of us getting on the first batch of CC+ plus boards and we wait patiently for the next batch.

Have you already ordered? If not, do so, 'cause Sandro just told me I was number six or so in the next batch.

How is everyone liking there's ? Chroma running cooler ? less MIDI lag ?, other things? Did you get he Midi interface option or are you using your syntech/cult/face still? and how do you like patch bank 3 ? : )

I'm still trying to understand the control change vs sysex stuff, but I guess I have a few months to figure that one out before the next batch of CC+'s. ;)

Tom Moravansky [21030431]

I haven't done significant testing as far as timing, power draw, etc, but my initial impressions are very favorable. The installation instructions were very clear, the cabling and rails, etc had enough slack to make positioning and final fitting easy.

As far as performance - I've been testing the MIDI in from various hardware sequencers and it seems like the timing and response is very tight. It's been years since I used a Chroma with the Syntech interface, but my impression is that the CC+ response/timing is very tight. (I opted for the complete version including external MIDI interface).

Volume and effects pedals and footswitches repost

Jim Russo [21030433]

Paul posted this in June without response, but i am also curious about it, so if anyone knows please respond. THX-James

Hi everyone,

Please can someone advise me on readily available possible alternatives for use as volume and effects pedals for my Chroma? Also footswitches to use for the Chromas sequence footswitch jack?

I'm still looking out for original Chroma ones but modern alternatives like Roland, Yamaha etc will do if there are any suitable ones you know of. Anything I might be able to buy readily in UK music shops or online would be great.

I have a Chroma dual footswitch for sustain etc, I only need help to choose suitable pedals for the above.

Paging Lloyd Trammel

Greg Montalbano, Analog Synthesizer Service

--please contact me regarding Chroma #0016.

Lloyd Trammell [21030016]


I just got back home today. Got a letter from you last night when I got in. What's up? I will answer email when I get back this evening. I no longer have this Chroma as I sold it and it was picked up by fedex to go somewhere, not sure where.

Greg Montalbano, Analog Synthesizer Service

Thanks --

The reason I was asking was that I received the Chroma via Fedex & had no idea who it was from, or why I was receiving it; however, today I finally heard from Pierre (who bought the thing from you & had it shipped to me for service).

Sorry to bother you -- now I finally know what's going on.

Chroma sings new song, I don't like it.

Ron Joseph [21030042+]

Hi everyone,

I need some help. I moved my Chroma from upstairs to downstairs and now she doesn't work.No lights LED etc. However, the power supply (nuc powered retrofit) chirps like a cricket.I have a voltmeter but I don't know what to check for. I'd hate to have to drive to NY city for repairs only to find out it was a simple fix. Thanks for any help in advance...

Paul Hackett-Evans [21010094]

Hi Ron,

I'm not sure what you mean by chirping, as I don't have a nuclear-style psu. But here's something that you may find useful to try.

I have the original powers supply in my Chroma, which is serviced regularly. The last time it was at Roy's (the engineer), he replaced a couple of resistors in the power supply that had drifted slightly off their precise value. The Chroma was working perfectly on test, then we moved it across to another bench to refit the case lid. After we did that, the Chroma was like yours - no boot-up.

The power supply was working perfectly, all measurements were absolutely spot-on. It turned out that the no-boot problem was due to a voice board having moved slightly when we carried the Chroma across Roy's workshop, it had poor contact with its motherboard. Roy re-seated the voice boards, then screwed the wooden retaining strap firmly down and the Chroma worked perfectly, and has done since.

It may help you to try extracting your voice boards, cleaning the contacts and reseating them securely, in case your Chroma's boot-up sequence is stopped by a poor connection to a voice board.

Good luck,


Ron Joseph [21030042+]


Thanks, reseating the voice cards did the trick.Funny,I checked almost every other connection.Why does a badly seated card stop the process? I figured the card would just fail the tuneup process. Again thanks for the help...

Paul Hackett-Evans [21010094]

Lovely - this is exactly one of the things a list like this is for! =)

CC+ Status/Availability Update

David Clarke [21030085++]

By way of a brief status update for those on the list - the initial CC+ build was very well received.

The units were first offered at the beginning of June, and just over a week later we had successfully taken orders for all of the circuit boards available in the first production run.

Those boards are now either well on their way or have been completely received by the purchasers (with some having already been installed and in use.)

As was recently noted by Jesper, whenever there's been further interest for the CC+ we've placed people's name on a 'want' list.

The minimum number required for another circuit board order is 10. We're currently at 7. After we place our next order there may be another delay while we collect up another batch of orders so if you were thinking about getting one, it might be a good idea to get in touch sooner (rather than later) so as to get in on the next build.

Thanks to all for your interest to date.

Jerry Leonard [21030100++]


Sign me up for 1 CC+ board. Please advise me about the payment process when you're ready.


Olli [21010284]

OK, i am in folks :-)

Dave Bradley [16330135]

I'm in too.

Luigi Castelli [21030825]


I'd like to be signed up for a CC+ board as well.


Jim Russo [21030433]

See what a little advertising can do Dave : ) James #1 ? on the wait list : )

David Gowin [21030611]

Me too Please!

Olli [21010284]

i think the run is complete?

Rob Vandivier [21030396]

1 here please.

Lance Ong

Will the CC+ board work in an Expander?


David Clarke [21030085++]

i think the run is complete?

10 is the minimum number needed to make an order, but we're not necessarily limited to 10.

Based on the flurry of interest today (wow!) it would seem that we'll easily meet the min. order requirement.

For those of you who e-mailed directly (as well as those who sent to the list) I'll follow-up via direct e-mail later this evening to confirm you're on the list.

For those of you still thinking about ordering, please feel free to get in touch. (If you let us know generally where you are in the world - North America, Europe, Asia, etc. - that would help too).

David Clarke [21030085++]

Will the CC+ board work in an Expander?

Yes: CPU Plus: One CPU/Program Load for Both the Chroma and Expander.

The board was designed make the CC+ hardware/firmware interchangable between the Chroma and Expander (unlike the original CPU, which had Chroma-specific PROMs or Expander-specific PROMs).

For the CC+ there's a user-interface parameter which will let you chose whether it should be set up for the Expander or Chroma Keyboard.

Edward Chen [21030674]

Hi David,

Hope the order has not gone out yet. Pls sign me up for one as well.

Luca Sasdelli [21010226]

Hi David,

please sign me for one too :-)

Krisnallah Sumy [21010282+]

Hi Dave,

Please also sign me up for the CC+board with midi

Thomas Story [21030352]

I would like to sign up for one with midi.

Put me on the list!

Chroma Cult on sale on eBay

Luca Sasdelli [21010226]

Hi all folks,

this to advertise that my Chroma Cult is on sale on eBay: Item #130018325729.

It comes from that 60-items batch that Ken Ypparila [21030229] did sell in 2001. Just to help if one seeks for a MIDI I/F without making changes within the monster.

Chris Ryan [21030691]

I wonder whether the CPU Plus is going to prompt a sell-off of Chroma parts it replaces. I noticed a couple of CPU boards for sale the other day (eBay item 180015621325).

There is also a voice board for auction, current bid US$31, ends August 23. Item #300018578146.

Here is the picture from the CPU boards auction:

CC+ Update

Sandro Sfregola [21010294]

Thank you to all for your continued interest in the CC+.

As evidenced by the notes to the list (as well as others directly to us), we've had a good amount of interest in the current CC+ order.

We had planned to start getting back in touch (with information on payment, etc.) this week; however, as order requests continue to come in (and as other list members may still be out on holidays) we're going to wait a few more days.

Specifically, we'll be taking requests on this current order up until the end of the month (August 31, midnight, EST). At that time we'll assess the total number of orders, and then start getting back in touch individually to reconfirm interest and to provide specifics in terms of expected delivery times, payment methods, desired method of shipment, etc.) [David will be getting back in touch with the people from North America, Sandro will be getting back in touch with the people from the EU.]

CC+ Feedback

Christian Kleine [21030210]

Hi List,

I received the CC+ today, installed it and i can only encourage every Chroma owner to buy it. The design and functionality is simply incredibly beautiful. The Chroma was always one of my favorite synths, now it is without any doubt from another universe.


btw. if anyone needs an untested JLCooper Chromaface for a few bucks, contact me offlist.

Jesper Ödemark [21010135]

Cool and congrat's!

If anyone of you in the first batch succesfully adds a knob box, please tell us 'cause that's my plan once batch two is ready and delivered. =)