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ChromaTalk Archives: January 2001

Keyfax Review

Chris Ryan [21030691]

I have posted a review of the Chroma from the book "Keyfax Omnibus Edition" (published 1996), with permission from the author, Julian Colbeck.

Happy 2001!

Sysex for Chroma Polaris

Wayne Feschuk

Does anyone know how to loose the casette on the Chroma Polaris and use sysex for bulk dumps instead. Using the cassette for saving and loading patch data patches is not always consistent enough.

Chris speculated that doing it over MIDI might be the best route, while not writing off the possibility of doing it over the Chroma Interface.

He mentioned the old Opcode Galaxy for Mac which had a librarian for the Polaris [suggesting sysex over MIDI]. Unfortunately I don't have a Mac. He mentioned the Chroma Cult interface, while cautioning it may not work on a Polaris.

Does anyone know if it's possible to get the Polaris operating on sysex instead of the cassette, and how to get it done?

Thanks

Wayne Feschuk

Chris Ryan [21030691]

[Chris] mentioned the Chroma Cult interface, while cautioning it may not work on a Polaris.

I e-mailed Ken Ypparila [21030229] (who produces the Chroma Cult MIDI retrofit), and got this reply:

"I have a polaris but never used the computer interface on the back for anything. It has a MIDI connection so I guess that's all you need. If you still have the manual I think there is a huge list of stuff the MIDI port could be used for."

Windows/Chroma interface - design error

Mark R. David [21030170+]

I hadn't intended to release a new version this soon, but I discovered a major design problem in my circuit this week. In the admittedly unlikely event that someone else is trying to build this thing, I've put a new version of the circuit design and the ChromaServer component out in [obsolete URL removed].

need help rigging a cassette interface cable

Matt Jasper

Hello-- I once parted with a Chroma when moving (I think it was one of the first 50, even) and have just now corrected that mistake by acquiring a Chroma with Chromacult midi. I'm using Sound Diver for Windows as an editor but would be interested in any tips about other editors for Windows/an old Mac II ...or if a Unisyn profile exists yet.

Anyway--I have a 5 pin din cable with the leads bare and ready for experimentation yet have had a hard time figuring out exactly which leads provide which function. If anyone out there knows which pins on that jack go to which function, I'd be grateful.... and could even send terrible free cds from my dead label. I have been able to get a faint (coming up maybe to the negative ten db mark on my cassette deck) signal of the modem-like patch saving tones yet for some reason can't get a strong signal when I try out all the permutations. And of course an even longer shot--if anyone has a cassette cable they want to sell, let me know.

Thanks............

Chris Ryan [21030691]

Hello-- I once parted with a Chroma when moving (I think it was one of the first 50, even) and have just now corrected that mistake by acquiring a Chroma with Chromacult midi. I'm using Sound Diver for Windows as an editor but would be interested in any tips about other editors for Windows/an old Mac II ...or if a Unisyn profile exists yet.

I got Mark of the Unicorn's Unisyn developer's kit but haven't had time to start a Chroma editor profile. I hope to get to this some day. Other software includes Galaxy (discontinued, librarian only) and Sound Quest (librarian only), as well as a couple of DOS utilities. See [editors & librarian listings in the Patches section (Mac OS X, Mac OS, Windows, MS-DOS, Apple II, Atari)] for more information.

David Clarke [21030085++]

... Anyway--I have a 5 pin din cable with the leads bare and ready for experimentation yet have had a hard time figuring out exactly which leads provide which function. If anyone out there knows which pins on that jack go to which function, I'd be grateful...

I'll write up some info (with a diagram, etc.) and post it to the list (hopefully before the end of the this coming weekend) [see below for Dave's later note] - but in the meantime, here's some quick info.

If you hold the 5 pin din connector in your hand, so that the pins are facing you you'd have:

    o
 o     o
o       o

    ^

where the "^" is the notch at the bottom of the din connector.

    3o
 2o    4o
1o      5o

    ^

If we number the pins (as above) then we have:

1 = MOTOR +
2 = TAPE AUDIO FROM CHROMA (i.e., used when you're doing tape dumps from the Chroma)
3 = Ground
4 = TAPE AUDIO TO CHROMA (i.e., where you insert audio into the Chroma)
5 = MOTOR -

The original cable has 3 connectors - a 1/8" black plug, a 1/8" grey plug and a smaller grey plug.

The 1/8" black plug has "ground" on the sleeve and TAPE AUDIO TO CHROMA on the tip.

The 1/8" grey plug has "ground" on the sleeve and TAPE AUDIO FROM CHROMA on the tip.

The smaller grey plug has MOTOR + on the tip and MOTOR - on the sleeve.

Note: The output signal from the Chroma is only 50-60mV (Vp-p).

Matt Jasper

chroma cassette & sounds wanted

Hello and thanks so much for the information. I found that the output I was getting was so low and difficult to preamp that I must be screwing something up & therefore wouldn't have a good enough signal to even try inputting. I'll use a better tape deck. May I post your email at my small page I have up for Chroma sounds & information? Also--I'm going to post mp3 audio of patches in audio cassette type format so if you feel bored enough to contribute a set of patches feel free.........anyone who sends a file will be credited. I'm especially interested in user modified sounds but also could use a file of the original Chroma Presets as I think 4 or 5 were missing from my machine when acquired.

Best Wishes,

Matt Jasper

Don Tillman

Note that the record output signal from the Chroma was intended to drive the microphone input of a portable cassette recorder. Microphone inputs are much lower level than line inputs.

These days it's hard to find a hifi cassette deck with microphone inputs. (Actually, these days it's hard to find a hifi cassette deck period.)

Matt Gerassimoff

It would be interesting to make a cable that connects a sound card in a PC to the Chroma's cassette interface. That way you could download sounds from a PC directly to the Chroma. That is of course if you don't have a MIDI interface and you have a PC.

Chris Ryan [21030691]

That's how I produced the sample audio bank at the site [see Patch Downloads].

Of course, on a Mac you don't need a sound card! :)

Dave Clarke wrote the utilities to convert from Galaxy (the format available on the site) to tape (audio .snd format) to parameter listings (text files).

I have a friend who's been doing some work in porting these to the Mac. Should even be Carbon (Mac OS X) compatible when they're done.

Nothing ever came of this; however, I will produce Mac OS X versions of these as time allows.

Matt Gerassimoff

I have a friend who's been doing some work in porting these to the Mac. Should even be Carbon (Mac OS X) compatible when they're done.

I compiled them up for linux with a couple of minor fixes. They run great. My Chroma is in dire need of a power supply. I got one on order and going the "Nuclear Powered Chroma" route. But I have the "cult" midi converter. I might create a chroma programmer that uses the MIDI interface under linux and release it if there is interest.

Eirikur Hallgrimsson [21030467+]

Linux

Matt,
I'd be very interested in a programmer for Linux. I code on Linux and could help.

Matt Gerassimoff

Well, when I get my power supply installed, I'll be able to work on it. I was planning on using PyQt (Python interface to Qt). It has worked great for prototyping and fast development. I do GUI interface, and development system programming and like the quick development setup of PyQt.

How about a Chroma realtime emulator? I was considering this as a potential project too. I looked at a program called pd (pure-data) that is similar to a program for the Mac called Max/MSP. Only it's free. I could add a couple of "externals" (basically plugin's) to the program to map the Chroma's oscillators, filters, modulators, etc to the paradigm. Then you could do offline development of a Chroma patch and then create a downloadable patch to the Chroma for performanace.

The other posibility is LADSPA (Linux Audio Developer's Siomple Plugin API) for the realtime virtual Chroma.

I've got alot of ideas for this stuff. Linux has "many" tools for sound and MIDI development. It's just a matter of time.

David Clarke [21030085++]

Info on Chroma Cassette Cable

All:

As promised, here is a mini write-up on the cassette cable for the Chroma.

I have attached a GIF to help identify which wires/signals go where (I tried to make the file as small as possible while still keeping it legible).

To try and avoid confusion, I've used the same pin numbering as in the Chroma schematics (the absolute pin numbers are different than I used in my last e-mail).

From the Chroma Performance Manual [Cassette Interface section]:

"You will notice that the Cassette Interface Cord has three plugs; a long grey plug, a long black plug, and a short grey plug. The long black plug should be inserted in the audio output (EARPHONE) jack. The long grey plug should be inserted in the audio input (MICROPHONE) jack, and the short grey plug should be inserted in the remote control jack."

With reference to the diagram, the "black" plug is the one filled in - the "grey" plugs are shown as hollow.

The actual pin/signal assignments are as follows:

1 = MOTOR +
2 = Ground (provided from the Chroma)
3 = MOTOR -
4 = RECORD (TAPE AUDIO FROM CHROMA - used when you're doing tape dumps from the Chroma)
5 = PLAYBACK (TAPE AUDIO TO CHROMA - used to insert audio into the Chroma)

Interpreting the diagram as words:

The long black plug has "ground" on the sleeve and TAPE AUDIO TO CHROMA on the tip.

The long grey plug has "ground" on the sleeve and TAPE AUDIO FROM CHROMA on the tip.

The smaller grey plug has MOTOR + on the tip and MOTOR - on the sleeve.

In terms of actual hardware, the "short" plug is approx. 2.5mm dia. x 12.5mm long. The "long" plugs are approx. 3.5mm dia. x 14.5mm long.

The RECORD signal (TAPE AUDIO FROM CHROMA) is output at a fixed level, approx. 50-60mV (peak-peak).

The PLAYBACK (TAPE AUDIO TO CHROMA) signal should be at least 1.9 volts (peak-peak) to ensure the internal electronics will be able to recognize it properly.

Expander for sale

Chris Ryan [21030691]

Rhodes Chroma Expander with Syntech midi interface and Chroma Cult memory expander. US$1500. Contact info on the Ads page at the site.

Chroma Power Supply cheap!!

Matt Gerassimoff

Hey,

I ordered and received the Power1 MAP80-4000 power supply in the Nuclear Power Chroma article referenced on the web page. My Chroma is dead currently and so I was looking to replace the supply. It was $24.95 including s/h at www.mpja.com. I read the mailing list archives about an interface board. (for the 5v analog and the powerfail circuit). Are there any left? How much just for the board?

Actually it would be nice to create a single board that has the molex connectors right on it. With a cable for the power supply. I can design the circuit, but as for getting the board built, I'm not sure there. But having an all-in-one board for all the connections would make for extremely simple and clean upgrade.

Even without the interface board, I think the whole upgrade will be below $50.

Expander - how rare?

Dave Bradley [16330135]

I finally appear to have scored an Expander (the one briefly advertised on Chris' site, to replace the one that was ripped off from me years ago.

As I await in terror the UPS delivery (tracking number doesn't show any record on the website; visions of smashed and crushed instrument, etc.) I'm wondering: just how rare is the Expander?

Does anybody know how many were made?

Paul Hackett-Evans [21010094]

Dave,
I'm not sure how many were made, but I do know that, apart from one or two which were brought into the country for specific individual players at their personal request, none were imported into the UK.

Being a Brit myself, as far as I'm concerned the Expander is rare! Hopefully less so in other parts of the world....?

Wish I had been able to buy the one you're hopefully getting!! Regards
Paul

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