Rhodes Chroma

This page is about my Rhodes Chroma Synthesiser.

My relation to this huge and heavy box is somewhat tense:
On one hand it produces lots of unique sounds and has a quite interesting architecture, on the other hand it's huge, heavy, and certainly not flawless in design which causes several problems from time to time.
The Chroma currently is non functional. There's a problem with the power supply. While I was testing the Chroma I had to switch the synth off and on many times and eventually the fuse blew. Not a big deal one might say, but this fuse is soldered in :-(
Until now I haven't had the time and space to take proper care of it.

Important link for Chroma owners:
This ultimate Chroma Site holds an absolutely astounding collection of information about this vintage synthesizer.

As you may notice I got this box from the USA years ago.
Shipping was quite worthwile then, today I wouldn't do that again.

My Chroma was stored in its Anvil Case the last three years. This is what happens, when the foam starts to deteriorate and gets into a chemical reaction with the finish.
Quite ugly, isn't it?
BTW, what does "Lifetime Warranty" mean?

Two micro controllers are responsible for the Chroma's interaction with the user and some other things. The CPU board at the right side reveals vast 3kByte of CMOS RAM and 16kByte of EPROMs (8x2kB).

The synth has eight voicecards each providing two voices. Those voices can be combined, the oscillators can crossmodulate each other, the filters provide different modes etc.
The VCOs response is 0,5V/Oct.

Thats probably the weakest (and heaviest) point of the Chroma: The power supply. Its design makes some of the older units behave strange since it's pretty sensitive to spikes from the power line.

Take a closer look at the controller and I/O cards. Notice the array of EPROMs and RAM memory chips.
Watch those AA cells so that they don't leak!

My Chroma is seriously ill at the moment. It takes ten or more attempts powering it on to make it boot properly one single time.
And now this fuse has blown.
This damn little thing is soldered in!

David Clarke kindly pointed me to a Field Change Note which explains why it's good to have this hardware patch. Quote: "This prevents the Chroma from mysteriously changing its own parameter, modifying programs, switching selections, tapping the tapper, etc."

(to be continued)

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