[sdiy] Using DG-series analog switches for PWM VCA

[Rutger Vlek]

Ha, and sometimes the choice for a solution can simply be driven by the parts you have in your drawer :). That's why I proposed the SSI2164, I've been prototyping a lot of stuff with that lately.

Rutger

On 13 jun 2018, at 14:52, Tom Wiltshire wrote:

> 
>> On 13 Jun 2018, at 12:21, Mattias Rickardsson <mr at analogue.org> wrote:
>> 
>> 2164 VCAs accept supplies down to at least +/- 4 V, so it shouldn't be a problem. They do show roughly a doubling in THD compared to the +/- 15 V supply according to the SSI2164 data I've seen so far, but that shouldn't really be any problem in a pedal. :-D
>> 
>> The PWM switch solution *might* be a better solution (for several values of "better") considering you already have access to the digital control for switches but perhaps not the analog CVs for VCAs, but certainly feels like a more complex solution when coming from analog. Do it! ;-)
> 
> 
> Yes, “several values of ‘better’” sums it up pretty well. I’ve already got a uP in the design, so producing the PWM control signals no big deal - what R.G.Keen ironically calls “a simple matter of programming”. And the filtering isn’t going to add much either, since there would already be an op-amp buffer on both ends, and those can easily be modified into filters instead. So I think I shall try it.
> 
> That said, as long as you don’t need battery power, I suppose the 2164 at 9V is ok - “within spec” at least, and it’s probably operation beyond that limit to some extent. Perhaps I’ll save that for something else.
> 
> Thanks all,
> Tom
> 
> 
> ==================
>       Electric Druid
> Synth & Stompbox DIY
> ==================
> 
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy