ChromaTalk Archives: February 2007
- Analog Bach
- Chroma on Craigslist
- expensive carcass in the UK (6 messages)
- 21030467 is 95% working (7)
- first (?) 2nd batch CC+ installed
- Replacement wood case parts available (13)
- Case hardware (3)
- On the Bench (3)
Chris Ryan  · Thu, 1 Feb 2007 21:11:07 -0800
Marco Rosano  has very kindly provided three excellent tracks from his forthcoming CD Analog Bach, recordings of baroque music on the Chroma. I really enjoy these; it's great to hear classical music played on a synthesizer with such musicality. And they come along with some inspiring musings about synthesizers as musical instruments, the impetus behind the recordings. Thanks, Marco!
Two sample tracks are now provided from the final release in 2010, as well as links to download the album or individual tracks from iTunes. See Analog Bach.
Chris Ryan  · Mon, 5 Feb 2007 16:25:48 -0500
Item ID 271069738. Appears to be in the Central Valley area of California. From the description: "Fender Rhodes Chroma Polyphonic Analog Synthesizer in fantastic condition. The wood has been entirely replaced with new curly maple and looks amazing. Features include 16 voices, velocity sensitive weighted piano action, multimode filters, 3 band EQ, HPF, LPF, and much more. Incredible sounding synth for pads, leads, and bass $2500."
Jesper Ödemark  · Mon, 12 Feb 2007 07:54:18 +0100
[eBay item 220080618735]
Lord Charge-too-much is back with a wrecked chroma. Looks like he once again used someone else's pictures since they're so small...
Chris Ryan  · Sun, 11 Feb 2007 23:07:28 -0800
For better pictures, see the instrument's registry entry.
Jesper Ödemark  · Mon, 12 Feb 2007 08:28:30 +0100
That's what I guessed too... He also sells other items I recently saw on the 'bay and those have exactly the same descriptions too. Being an EDP/OSC-devotee I couldn't miss the wrecked OSCar he has in his keeping...
Olli  · Mon, 12 Feb 2007 10:00:02 +0100
hahaha, those "pictures" are a joke. if we assume that he doesn't have the lowest bandwidth dialup imaginable, there can only be one purpose of reducing the size of those photos as much as he did...
Rob Belcher  · Mon, 12 Feb 2007 09:03:09 +0000
What makes me laugh, is that he bought the Chroma for $500, probably paid $400 to ship it, say $100 Customs/vat etc.. So, say $1000 in total. Thats about £550, i just dont see its worth going to all that hassle, just to turn it around on Ebay for £800. Sure i suppose for him, £250 profit for doing nothing is good, but it seems like a hell of a lot of hassle to me...
I wonder why he bought it in the first place? I wasnt sure if he was an enthusiast or not, now its quite clear to me that he is selling synths purely for financial reasons.... Fair enough i guess... Some of these auctions just seem a little bit odd to me...
Still £800 isnt too bad for a Chroma that needs some work, especially in the UK as we have the great Roy Paynter who will get these beasts up and running again...
I may have been tempted myself, but i have 2x Expanders both in for a service at the moment to worry about (besides the Chroma keyboard is too bloody big!)
Rob Belcher  · Mon, 12 Feb 2007 09:09:35 +0000
It simply because he is too lazy to take his own pics... honestly!... its crazy... with some high res pics he would probably get a lot more money for his items! He just buys stuff Ebay US, copies and pastes the text and pics, obviously when you copy pics from Ebay they are rubbish... Anyway, good luck to him...
Randel Osborne  · Mon, 12 Feb 2007 09:54:22 -0500
But the last 5% might drive me crazy!
After a long time on the bench, a new switching PS, a brilliant CC+ computer, a "new" I/O board, and a pile of parts, 21030467 is mostly working.
In fact, all voices calibrate with no errors, MIDI in works, and I've used the instrument on several tracks that I'm currently recording.
Alas, the keyboard is not working, and I'm soliciting advice and suggestions from the group.
I've replaced the 74LS145s on the Stack Switch Assemblies, as well as Z34 and Z35 on the I/O board, and verified the proper voltages on the Stack Switch boards.
The I/O board that is in the instrument was purchased as "NOS" from eBay a while back, but was missing LEDs, DAC, etc.
I've swapped Z31 and Z33 with no positive outcome except one of my Z33s produces no 5v logic signals on the data busses, so I assume it has failed.
The I/O board had the K MASK signal (Z49 pin 10) jumpered to ground, but I restored it's proper path to Z29.
My diagnostic tools are limited to a 2-channel scope and a multimiter, so I can "see" data, but not interpret.
I have verified the clock on the Z31 processor.
I have not yet replaced Z32, Z37 or Z38, I suppose that I can add them to the list.
Without a logic analyzer, can anyone suggest what the data on pins 12-19 of Z31 should look like, on a scope? Or what I could use to trigger the scope? At the moment they look like 5v square waves that have been pulse-with-modulated by something complex.
Rob Belcher  · Mon, 12 Feb 2007 14:59:08 +0000
Hello list, Has the european CC+ boards shipped yet i havent recieved mine yet? Or are they just about to ship...? Sandro?
Jesper Ödemark  · Tue, 13 Feb 2007 06:41:47 +0100
Mine is on its way AFAIK since Sandro asked for my shipping address just the other day...
Rob Belcher  · Tue, 13 Feb 2007 10:50:12 +0000
Oh thats great, i should get mine soon too then!
Olli  · Tue, 13 Feb 2007 12:36:27 +0100
Randel Osborne  · Tue, 13 Feb 2007 07:30:22 -0500
Hold the phone!
I made a breakthrough!
My "New Old Stock" I/O board had 2 more very deliberate cuts in the traces that disconnected Z34's clock from the scanning computer's clock.
I restored these connections, and half of the keyboard started working, in 8-note groups.
|Next 8||2 tones per key|
|Next 8||2 tones per key|
I suppose that I'm back to evaluating the Stack Switch boards and associated logic, and any thoughts or words of wisdom would be appreciated.
David Clarke [21030085++] · Sat, 17 Feb 2007 16:35:34 -0500
Randel - I'm guessing you've already gotten to the bottom on this now; however, if it still actively being investigated, the signals in/out of the the 74LS145 (Z1) on the stack switch assemblies will be good places to start.
To make it easier, you can split the connection between the right and left stack switches (to rule out the effect of the left on the right).
If the top keys still behave as above, then grab a block of 8 that don't get detected and work backwards from there.
If I were to make a guess I'd perhaps suggest looking specifically at the KA2 and /KA2 signals. The dual-trace scope should be all that you'll need.
Good luck, and let us know how you make out.
Jesper Ödemark  · Thu, 22 Feb 2007 06:21:47 +0100
While the snow was (is) pouring down over Sweden (first time in in 11 months in my parts) and I had a night of insomnia I brought out the Chroma from the studio dusk and got to work.
The very good written online manual was easier to follow than a building instruction from IKEA and I encountered no trouble. But the fiddliest part was installing the new midi port on the back, darn small washers!
It took me about an hour, but I took breaks making tea and taking it slow indeed not to wake the rest of the family asleep on the on the first floor below.
Since I'd never been inside my Chroma before I took the chance of looking at the engineering and design too. I love the girl even more now. But I don't think I've seen a more massive PSU in anything I've opened before - enormous! My battery is apparently quite new and of the lithium type. I have also had a bit "harder" feel to a few keys in the second octave. This was easily fixed since the reason was internal cables weighting the keys down. I could even use the supplied plastic straps not used at the installation of the CC+.
Also, I decided to keep the cover for the midi port inside the Chroma and just screwed in it's old place in a 90 degree angle. That way I won't lose it.
Off to some playing and update manual reading... but be sure to "[set split]+" if you're not used to the tapper. I haven't heard the bastard before but it sure is annoying!
Lots of greetings and thanks to David and Sandro for amazing work. I'll get back after some testing with my midi knob box...
Dave Bradley  · Thu, 22 Feb 2007 10:47:14 -0600
Wes over at Analogics is now making cherry (and other hardwood) replacement case parts for Chroma. Check out the pics of flame maple minimoog cases.
Picture from the site:
Jesper Ödemark  · Thu, 22 Feb 2007 19:04:52 +0100
I thought that was quite ugly to be honest...
But that reminds me to check with my dad if he still has some cherry wood left. I plan to make a chroma-styled look for my knob box... ...which in fact worked immediately though far from everything was assigned like I want it to be. But it was a joy fiddling the filter and resonance with knobs!
Chris Ryan  · Thu, 22 Feb 2007 13:22:59 -0500
I thought that was quite ugly to be honest...
Why? With some stain I think it would look much like the original.
Dave Bradley  · Thu, 22 Feb 2007 12:44:14 -0600
Did you mean the Chroma replacement panels or the flashy Minimoog case?
Jesper Ödemark  · Thu, 22 Feb 2007 20:01:44 +0100
I stayed on-topic! :) (so, chroma)
I think all these sellers of end cheeks etc are good since apparently people want them, but I cannot see the point really. To me they're musical instruments. In second place historical artifacts, followed by pieces of engineering magic etc. I never notice the scratches on my Chroma wood parts 'cause it's deep "buried" beneath/behind/beside other gear. But one day maybe? But then I'd rather bring back the life of the wood that is still there instead.
Jesper Ödemark  · Thu, 22 Feb 2007 20:31:19 +0100
It was the light colour I meant. Yes, otherwise it's good work. But quite a price tag... Most old synths look good in the wood they was released in. I like patina and age... but that's me. ;)
Dave Bradley  · Thu, 22 Feb 2007 15:29:07 -0600
Well, those are unfinished still <g>. Put some lacquer on them and they will darken up quite nicely.
I'm looking into having a set made for my Expander too. Why? Because then I could get the wood to match nicely. My Chroma is an earlier unit with nice wood, albeit with foam rot and dings. It could be refinished.
However, my Expander is probably one of the last ones ever built. The wood on it is plain, doesn't match the Chroma, and looks substandard.
Jesper Ödemark  · Fri, 23 Feb 2007 07:28:19 +0100
Or get someone with an old Expander to order a new set and buy his old wooden parts and get a vintage-looking setup! ;)
Jimmy Moyer  · Fri, 23 Feb 2007 01:50:55 -0500
The wood finish on my Chroma shows a few dings and scratches and some 'aligatoring'(?) near the keyboard, but no foam rot. (Mine has never been in the case except when actually being moved.)
I always had the idea that both of these problems were caused by the use of some wood finishing product that never completely hardened, shellac perhaps? Admittedly I know zero about wood finishing.
Anyone know how easy it is to disassemble the finished wood parts and any rough idea about what a local wood refinisher would charge?
Dave Bradley  · Fri, 23 Feb 2007 08:52:09 -0600
I think they used lacquer, as on a fine furniture finish. Perfectly durable, except when exposed to chemical reactions from foam deteriorating in the heat.
Jesper Ödemark  · Fri, 23 Feb 2007 19:08:49 +0100
Is the foam problem related to heat? I didn't know that. My case is quite bad, but not sticky, more porous. But on the other hand, it's never been further south than mid-Germany! ;)
Martijn · Sat, 24 Feb 2007 11:05:00 +0100
Check out the pics of flame maple minimoog cases.
I can assure you that it looks even better in real life. I completely rebuilt a Minimoog for one of my clients with that maple case Together with a new frontplate, new knobs and new keys it looked absolutely gorgeous! :-)
Jesper Ödemark  · Wed, 28 Feb 2007 07:35:31 +0100
thinking about all these modified Chroma cases
Anyone seen or have had the fuxxed up idea if a Chroma in Chrome? ;)
Jimmy Moyer  · Fri, 23 Feb 2007 01:57:01 -0500
On another beautification drift, years ago my back panel screws were getting to be a bit beat up and I replaced them with (gasp!) plain nickel hardware. The Chroma was back to the wall then and not visible. Now in a new place the nickel hardware stands out badly. I got a bag of nice new black screws on ebay for a few bucks.
Public service: Since I have many I don't need, if anyone would like to refresh their back panel screws I'll be happy to throw a few in an envelope and post them.
I suppose I'll also get some for the front panel which seem to be the same, just longer. I've not found a source for the brass countersunk ones on the top. Mine of those are cosmetically OK, but all partially stripped. Anyone know a source for those?
Michael Joyce  · Fri, 23 Feb 2007 08:59:59 +0000
Hi Mick joyce here. I could do with replacing the back and the top screws on my Chroma please let me know if there are any left cheers.
Dave Bradley  · Fri, 23 Feb 2007 08:53:33 -0600
I don't know if they have them, but for my other screw needs I've used Aaron's Machine Screws. Google them.
Randel Osborne  · Tue, 27 Feb 2007 19:58:01 -0500
For those that are interested, I have a small photo essay of the work that I have done on my recently resurrected Chroma.
Jesper Ödemark  · Wed, 28 Feb 2007 07:42:45 +0100
Weird to have the wires for the CC+ going left instead of right along the side of the Chroma. Any particular reason for this?
Randel Osborne  · Wed, 28 Feb 2007 12:04:16 -0500
There is no particular reason for my wire routing - I just wanted to keep things tidy, and had a bundle going to the left.
My new power supply also meant that I had to do a little creative wire management.
In addition, having the Chroma on the bench for nearly 2 years meant that many of the wires lost their "natural" shape, and had to be wrangled back into position.