Yamaha CS80

ahhhh, thanks for the thought, JH. that makes sense. i would rather not pioneer a mod on a synth that is as rare as this, but it seems to be very sensible and almost simple. im envisioning nothing more than a 3-5 ft umbilical-style cord with a multi-pin connector that screws in(my trident console has one that would work perfectly), mounted in the base of the chassis, right where the PSU is now. then you could set the psu on the floor within a few feet of the base of the chassis(of course mounted in its own chassis!).

i wonder, how much impedance could be lost between 8" and 5'? (i guess thats a question for my multimeter.)



"JH." <jhaible@...> wrote:                               I've never done this (in fact, my CS-80 isn't even in my home yet), but I'll 
 offer one thought nevertheless:
 
 The GND impedance may be a problem.
 
 Linear VCOs are very sensitive to small offset voltages in the low frequency 
 range, so a voltage drop across the GND connection may be a problem. I have 
 that theory, which isn't any more than a gut feeling right now, and may be 
 totally wrong, that the slight coupling via voltage drop *inside* the CS-80 
 may play a role in it's increadible lush-ness - then a longer GND path might 
 turn the feature into a problem.
 But then again there's a servo sensing for the PSU regulation if memory 
 serves - that would *allow* a rmote PSU (with sense and power wires both 
 going thru the umbilical cord).
 
 JH.
 
 ----- Original Message ----- 
 From: "rj krohn" <r_j_d_2.phila@...>
 To: <yamahacs80@yahoogroups.com>
 Sent: Tuesday, November 06, 2007 7:31 PM
 Subject: [yamahacs80] CS80 PSU mod-anyone ever done this?
 
 hi folks, i wanted to ask why a particular mod has never been discussed, or 
 done, to my knowledge on CS80's. hoping for some practical answers, to see 
 if i consider should setting out on this.
 
 it seems like it would be relatively easy to detach the PSU from the CS80, 
 and make it an external unit. im assuming that most(if not all) of the 
 reknowned pitch instability/temperature issues were due to the massive 
 PSU/input transformer. after seeing this firsthand, i see there are just two 
 harnesses and a ground wire that connect to the rest of the synth. it seems 
 like it would be pretty easy to take the PSU out, install 1 or 2 connectors 
 to adapt the harnesses to, and build an external box for the PSU. there cant 
 be more than 16-18 total harness pins for the rails of the PSU. by now, im 
 sure every cs80 in existence is a studio unit, and this wouldnt be too 
 inconvenient, and could potentially help the stability. of course, the 
 connector would have to be a screw-in type that could be well secured to the 
 chassis.
 
 is there a reason this hasnt been done, or has this been covered already, 
 and a terrible idea for some reason? thanks guys!
 
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