[sdiy] lots of VCAs on one PCB

[Kyle Stephens]

"THAT" sounds even better than what I suggested :)

Andreas, you mean these, right?

http://www.thatcorp.com/2181-series_Trimmable_Blackmer_IC_Voltage-Controlled_Amplifiers.html

Either of your joystick projects aside, a big ol' load of VCAs on one board would be useful for lots of folks, especially if the PCB could have perforations in groups of say 4 VCAs, as to spread your VCAs over multiple individual modules as you saw fit. No one needs 16 'regular', patchable VCAs, even without input and CV level pots and AC/DC coupling switches, in *one* module, right? Least that sounds like a recipe for clutter - one in, out, and CV in per VCA = 48 jacks O_o. Even with some master CV 'driver' input and a single summed output, that's still 18 jacks.

Though to each their own if the board was 'modular' in its own right like I suggest. It would make for a useful VC building block. Maybe just leave some board space for the parts that would allow for an expo CV response...(or have a perfboard daugherboard if that won't fit).

Has this strummed up some interest for anyone to peruse this further? (Don't mean to hijack your thread Derek, I just see so many possibilities!)


_Kyle

--- On Mon, 11/23/09, Andreas Wetterberg <andreas at wetterberg.dk> wrote:

> From: Andreas Wetterberg <andreas at wetterberg.dk>
> Subject: Re: [sdiy] lots of VCAs on one PCB
> To: "Synth DIY" <synth-diy at dropmix.xs4all.nl>
> Date: Monday, November 23, 2009, 10:45 PM
> I would think that a THAT vca cluster
> would be the best way to go on this.
> I think it's about time this gets some cool boards made for
> it - if you build the project in a way that can be used for
> other, perhaps more generic things, then I'd be very
> interested in the outcome.
> 
> Andreas
> (who keeps meaning to start a THAT project... and who also
> has some joysticks ;) )
> --
> 
> Derek Holzer skrev:
> > Howdy all,
> > 
> > I'm looking at building a joystick controlled 4x4
> matrix mixer, which requires 16 VCAs when it's all added up.
> It would be for control voltage, so a linear VCA is
> required. I've looked at the Thomas Henry VCA, which is
> pretty simple and quite nice, but all the layouts I've found
> for it are fairly large.
> > 
> > It struck me that a vocoder would need approximately
> the same amount of VCAs (depending on the number of
> analysis/resynthesis channels of course), so there must be
> some layout someplace that has a lot of VCAs packed together
> on one PCB board.
> > 
> > Can anyone point me to a layout that packs so much
> into a fairly small space (one Eurocard sized PCB
> 100x120mm)? Or a super basic linear VCA schemo that could be
> laid out in such a way? Alternately, is there anyone
> interested in working with me to design such a thing? I'd be
> willing to invest something in getting PCBs made in this
> case.
> > 
> > Best!
> > Derek
> > 
> 
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