Yamaha CS80

Well, I certainly love the mods on my CS-50:

Bringing out the CVs and Gates, and a 5th, monophonic gate.
I derive the highest and lowest note from that externally, run it thru a log 
converter, and control two V/Oct monosynths that double the lead and bass 
line.
And I have 4 LEDs for the Gates (externally) that are increadibly helpful 
for tuning the synth.
Also, I re-routed the Suboscillator Sine wave to the aftertouch->VCO path. 
that way I can add sine vibrato by aftertouch, and still can use other 
sources (like noise, or the synth's main output fed back to the external 
input) for VCF and VCA.
Also, I bring out the Aftertouch, the Sub Oscillator, the PWM oscillator and 
the Ring Mod oscillator for external use.
It's nice to sweep a VC Phaser by Aftertouch, or to do some VC stereo 
panning along with the PWM ...

I wouldn't build any FX device into the synth, though. There's so many 
differend FX boxes I want to try, so it's a good thing to have them 
separately.

JH.

----- Original Message ----- 
From: <blchrr@...>
To: <yamahacs80@yahoogroups.com>
Sent: Tuesday, November 06, 2007 11:01 PM
Subject: [yamahacs80] Re: CS80 PSU mod-anyone ever done this?


fwiw, i went down the route of modding the cs80 with some external fx built
into the unit... (changing the Cs80 chorus for a dc-2 circuit and changing
the tremolo circuit for a PH-3 circuit)
it was a BAD idea, DO NOT mod classic synths, leave them as they are...
Fortunately i only modified (drilled for extra pots) the modulation panel, i
managed to source another modulation panel and am changing it back
completely to a standard unit...
My own fault... but my answer is DONT modify the Cs80, work with what you
have...

> 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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Regards,
Rob Belcher
www.myspace.com/duplx



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