Yamaha CS80

Hi everyone,
Was wondering if anyone here could maybe answer a small qustion I've been curious about. The CS80 uses 2 different chips for the VCF and the VCA envelopes (152 and 159) but the CS70 uses the same chip for both these jobs - the 159. What would happen in an '80 if you replaced the VCF chip with a 159?

Looking on the schematic they have identical pin-out 'names'..!?

Cheers,
TOM

the CS80 Filter envelope is not ADSR....it is ADR with ILand
AL....meaning sustain level is set with the lowpass and highpass
filter.....it is the start levels the peak levels and end levels which
are additive or subtractive from these points...in the VCA, the CS80
is ADSR

-----Original message-----
From: "Quazimodo" noddyspuncture@...
Date: Wed, 20 Jan 2010 03:38:06 -0700
To: yamahacs80@yahoogroups.com
Subject: [yamahacs80] Out of interest..?

Hi everyone,
Was wondering if anyone here could maybe answer a small qustion I've
been curious about. The CS80 uses 2 different chips for the VCF and
the VCA envelopes (152 and 159) but the CS70 uses the same chip for
both these jobs - the 159. What would happen in an '80 if you replaced
the VCF chip with a 159?

Looking on the schematic they have identical pin-out 'names'..!?

Cheers,
TOM




[Non-text portions of this message have been removed]

--- In yamahacs80@yahoogroups.com, "Laurie Curry" <laurie@...> wrote:
>
> the CS80 Filter envelope is not ADSR....it is ADR with ILand
> AL....meaning sustain level is set with the lowpass and highpass
> filter.....it is the start levels the peak levels and end levels which
> are additive or subtractive from these points...in the VCA, the CS80
> is ADSR
> -----Original message-----
> From: "Quazimodo" noddyspuncture@...
> Date: Wed, 20 Jan 2010 03:38:06 -0700
> To: yamahacs80@yahoogroups.com
> Subject: [yamahacs80] Out of interest..?
> 
> Hi everyone,
> Was wondering if anyone here could maybe answer a small qustion I've
> been curious about. The CS80 uses 2 different chips for the VCF and
> the VCA envelopes (152 and 159) but the CS70 uses the same chip for
> both these jobs - the 159. What would happen in an '80 if you replaced
> the VCF chip with a 159?
> 
> Looking on the schematic they have identical pin-out 'names'..!?

Yes - if you look at the M-Board schematic, you'll see that the 
VCA EG (IG00159) has an Il (initial level) pin, but it's just tied to ground.  Likewise, the VCF EG (IG00152) has a Sl (sustain level) pin, but tied to ground.  On my old CS60, I modified all 8 M-Boards to swap the Il and Sl pins on the VCF EGs so they were "normal" ADSR, which made sense to me.  Of course, it messed up most of the presets :)

The IG00159 has the Al (attach level), which the other chip doesn't. 

 David