REI <==> Reverse Engineering, Inc.
Old Crow's Synth Shop -- The yamaha CS-50
Although the CS-80 is in a class by itself, this does not mean the CS-50
and 60 aren't quality instruments. In fact, some things are better done
on a CS-50 than the 80 simply due to the fell of the keyboard action. The
CS-80 has the ideal touch for those who prefer the piano, but the CS-50
and to a lesser degree the CS-60--I say lesser because the action is
longer and thus a little less crisp due to the extra mass--are very good
at sharp attack-style notes and chords--something that just can't be done
on a weight keyboard.
Part of this is based on the fact the aftertouch, though monophonic, is
not based on force sensing resistors but instead on a light source and
photoresistor. The photoresistor alone has "fast to lose resistance, slow
regain resistance" that imparts a sort of fixed attack-release that sound
very nice as part of a pizzacato or staccato playing style for a given
phrase. On the CS-50, with the lower-inertia 49-note keyboard, for a
composer this is a very useful tool.
Since the CS-50 shares the exact same voice cards (save for some
resistor values changed to select octaves differently than the '80), any
sound is directly transferrable from one channel of the CS-80 to the CS-50
or CS-60. Since all three machines have the exact same ring modulator and
controls, the same "breath phrasing" can be applied. Vangelis is a master
of this technique.
Restoring a Trashed CS-50
I bought this machine originally for use as spare parts for my CS-80,
but after reading Juergen Haible's account of the aftertouch feel of his
CS-50 and experimenting with some lead-type sounds, I decided that the
machine should live its own life. The problem is that the my CS-50 got so
manhandled by a popular parcel shipping service (UPS) that
considerable internal damage was done. When I opened the shipping carton
and an electrolytic cap fell out, right away I knew something was not
right. Even so, I set out to repair the beast...
The 10kg power supply was sheared loose and went on a rampage inside the case.
Note the front panel slider potentiometers that were POUNDED FLAT!
I made the new board in a local circuit board etching lab, salvaged
some parts from the broken board, and constructed the new one. It works
fine, even if the layout is a little different due to what parts I had on
hand formfactor-wise versus what was originally used.
Rebuilt and remounted power
Replaced some 4000-series CMOS
chips on the KAS and SH boards. Tunes up much better now.
(substitute letters for numbers to obtain valid address)
Scott Rider -- email@example.com