voltage

[rhdwave]

Hey all, another voltage question for a newbie: should there be voltage at the input pin of an opamp? if so, using an lm386 does anybody know the ratio compared to the v+ that it should be?

much thanks!

[chunks717]

around mid way between 9 and 0 in alot of audio cases.........whats the circuit?

[rhdwave]

It's a clean boost from Brian Wampler's book, but i modded it by putting a switch before the input pin to give two possibilities on input caps.  I'm getting no output at the moment, and trying to debug.

[chunks717]

did it work before the mod?
If so, it is easier to switch a cap in parallel to make it bigger,
(they add this way) so put your smallest value on the board, like
the schem. shows, and wire the switch so it puts the larger in
parallel with the smaller (both caps share both nodes,
or connection to the board)...........see?