[sdiy] Recommendations for Cleanest Multi VCA chip?

[Steve Ridley]

> Are  any of these in production & easily available (& where)?  and, are
> there any published schematics of VCAs using them?

The THAT 2180 was available in Europe from Profusion at
around £4 UK last time I looked (a few months ago).  I don't
know who distributes them in the USA, but I guess THAT
Corporation could tell you.

They have a big advantage over the SSM and Curtis devices - a
huge amount of pro and semi pro audio gear uses the THAT
(formerly dBX) VCAs, so there are lot's of them around and they
are not likely to disappear tomorrow.  The 2051 etc are older
versions of the same device.  Most the top end mixers (SSL etc)
use them.  I've worked on a lot of this gear for a lot of years and
can only remember one dying ever, so spares departments will
probably have them on the shelved gathering dust even if THAT
Corp disappear tomorrow.

Incidentally, Serge used a simplified discrete version of these
VCAs in many of his VCFs and VCAs (maybe still does).
Just a dual opamp and four transistors as far as I remember, so
as a last resort maybe you could roll your own?

All these VCAs are very good, but all are exponential.  Is there
a good linear response VCA out there - I mean significantly better
than the 13600 etc and without resorting to a log converter and
an expo VCA?


Steve