[sdiy] RE: [sdiy] asm-1 vcaÄs and the SSM 2024

[Gene Stopp]

I can answer #1 - yes, the ASM-1 VCA has linear CV-to-amplitude response.
For historical context, it's the Walter Jung one where the CA3080 minus
power rail is driven by the CV summer op-amp, as reprinted in Electronotes
(#61 I believe).

assuming you can find a CA3080 of course :)

- Gene


-----Original Message-----
From: owner-synth-diy at dropmix.xs4all.nl
[mailto:owner-synth-diy at dropmix.xs4all.nl]On Behalf Of Nils Pipenbrinck
Sent: Friday, October 29, 2004 2:28 PM
To: synth-diy at dropmix.xs4all.nl
Subject: [sdiy] asm-1 vcaÄs and the SSM 2024


Ladies and Gentlemen,

I want to replace the VCA's of the ASM-1 by a SSM2024 based circuit. I 
don't have any good reason but the fact that I have a little pile of 
those chips lying around on my workbench.

Befor I start to do a breadboard i have some questions:

* The CV-input of the ASM-1 VCA is linear, right?

* Is there any secret wisdom about the SSM2024 that I should know about? 
There's little discussion about it (anad it's a still-in-production 
VCA-Chip). Ot's noisy as? Does it has a horrible CV-feedthrough? Does it 
take eat  up more milliampere than  a  TTL-circuit? I'd like to  know 
about it's drawbacks before I start to breadboard.

* What's the recommended maximal deltaV at the SSM2024 input? When I 
look at the datasheet-examples it loos like the gain-cells of the 2024 
look like ordinary ota's with the negative input grounded. My rule of 
thumb value would be to scale the input down to something between 100 
and 150 millivolts to keep the signal  as linear as possible. Is that ok?

Thanks,
  Nils