question about audio OP amp

[Scott Gravenhorst]

On Thu, 09 Jul 1998 22:59:39 GMT, chordman at flash.net (Scott
Gravenhorst) wrote:

>Mind if I pipe in?  <g>  r_gain can be a variable resistor (pot) wired
>like a rheostat like mine (use the center pin and one side, making
>sure that when fully clockwise you get max resistance).  I didn't draw
>it that way because pots are more expensive than fixed Rs and panel
>space is always a problem.  My unit actually has a gain pot and a
>level pot.  The gain pot goes from a gain of 1 to around 450 when wide
>open.

Oh yes, in series with the gain pot, put a fixed resistor equal to the
input resistor, otherwise some of the gain pots rotation will be
wasted as gain of 1 until it's resitance goes above whatever the input
R is.  I have a 2 meg pot in series with a 4.7k fixed R because my
input R is 4.7k.  A small difference, but it allows full use of the
pot.

-- Scott Gravenhorst
-- FatMan Site: www.teklab.com/~chordman