Vintage Synth Repair

At 12:59 Uhr +0000 24.07.2011, Boddington wrote:
> I'm referring to the upper row: AR gain.

That's not what it is called and labelled. As we can see it is called "VCA
Gain" and is supposed to do exactly what you describe. So there's no actual
problem here; for "normal" playing this slider needs to be in the bottom
position. You only raise it for "drone" sounds that are supposed to go on
forever.

I believe mainly ARP synths have this feature (I've seen it on the 2600,
Odyssey and Axxe); and it seems to be one of the most typical sources of
confusion. I recently sold a MkII and of course the buyer also called to
ask if there is anything wrong with it because the sound wouldn't go away
completely. There are even more prominent users having encountered this: I
recall a story that an ARP representative delivered a 2600 to Joe Zawinul
(of Weather Report fame); and a few days later he got a call from Joe "this
is a totally great sounding instrument, but how do I make it stop?". (I
think the story is in the "Vintage Synthesizers" book by Mark Vail; I just
can't find my copy at the moment.)

So let's conclude this with a quote from the Odyssey Owner's Manual:

"The VCA GAIN control has nothing to do with the keyboard. The VCA Gain
control allows a certain amount of signal to pass through the VCA at all
times."


I'll think about the CV problem later.