[sdiy] Circuit Boards / kits

[David Moylan]

Roy J. Tellason wrote:
> 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.
> 
Didn't Arp use this configuration too?  I know there are some of this 
type in the Omni2.

Dave