All about the Roland Jupiter-series

-----Original Message-----
From: Paul Schreiber [mailto:synth1@...] 
Sent: Friday, January 07, 2000 6:15 AM
To: analog heaven; Qi
Subject: Re: [AH] << Jupiter 6 Popping on Attack and Release >>


According to the Service Manual, this *is a trim* on the pc board. It is
called
"DC Balance".

Now, this trimmer is VR10.

Also....on serial numbers 333000 and up, there are the following changes to
the VCA
(it is maked "For Perfect DC Balance Mod"....Ha Ha Ha)

Part    Was   Changed To

C117  22pf     150pf
R77   1.8k       47 ohms
R82   33k     6.8k
R81   100k    22k
R87   430k    140k

But the *main* thing is they added a C120, a 47uf, non-polar cap in series
with R82.

What is strange is that there is ANOTHER VCA *before this one*, a CEM3360
which is
driven by the EG. This other VCA is for Master Volume. And it messes up the
world.

In either case: adjust VR10 with a small screwdriver to minimize the pops.

Paul Schreiber:  BSEE, MSEE, EIEIO
Synthesis Technology
www.synthtech.com <<<VCAs that don't pop



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