[sdiy] stupid non-inverting opamp

[Don Tillman]

   > Date: Wed, 25 Jan 2006 14:22:36 -0800
   > From: Tom Arnold <xyzzy at sysabend.org>
   > 
   > http://www.themusic.net/rmp1-preamp.jpg
   > 
   > In short, it doesnt work.  Looking at the circuit I dont understand it.  I
   > see the feedback I'd expect ( R3 ) but then theres the outside feedback loop
   > of the pot, C4, and R2.  I just dont grok what was being done here, it
   > almost looks like a tone control vs a plain preamp.

This is a preamp circuit that a., does not invert, b., provides
variable gain, c., allows for gain less than unity, and d., doesn't
introduce noise by cutting the signal level and then applying gain
again.

  -- Don

-- 
Don Tillman
Palo Alto, California
don at till.com
http://www.till.com