[sdiy] Circuit Boards / kits

[Roy J. Tellason]

On Thursday 25 September 2008 08:33, harrybissell at wowway.com wrote:
> On Wed, 24 Sep 2008 18:22:38 -0400, Roy J. Tellason wrote
>
> > So what do they use for a VCA?
>
> A differential pair, a transistor to sink current through the emitters,
> and an opamp to revover the signal.  I added 1% resistors and it works
> very well.  I think its a 741 (or 748)

I have a vague recollection of seeing something of the sort before.  I think I 
had a TI book that featured a circuit like that.  I haven't seen it lately so 
I don't recall what particular amplifier it used or whether it used 1% 
resistors though.

> schematics are online (somewhere)

Hmm.

-- 
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space,  a critter that can
be killed but can't be tamed.  --Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James 
M Dakin