I need a bit of help with this dead simple circuit..

[Neutral]

I have just built the GGG mini mixer :
http://www.generalguitargadgets.com/v2/diagrams/mixer_sc.gif

I am getting no signal through it but the LED is on.

I have double checked all connections.

I used a TOL082 dual op amp:
http://www.st.com/stonline/books/pdf/docs/2300.pdf
It has the same pin out.

Here are the volt readings from it:
pin
1.  -4.3
2.  -4.3
3.  -4.3
4.  0
5.  -4.3
6.  -4.3
7.  -4.3
8.  9

Any help greatly appreciated.
It's such a simple circuit, but I can't work it out :oops:

Thanks

[Ansil]

do you have a audio probe??  if not build one for testing purposes.. its so you can trace the audio from input to output  and see where the signal stops..  other things to do.. check and see along the way.. put one end of the multimeter on ground and probe with the posotive end and check all the parts where the signal goes.. ie wherever there should be audio signal from the input jack through the circuit. there should be resistance to ground..  if you find a spot that is grounding out.. then you have issues.

[Ansil]

also shouldn't there be a current limiting resistor to the opamps..  hmm  don't knwo if that would make a hill of beans difference. though.  next time use lm386's  no voltage bias.. lol   its a personal preference of mine..  
:twisted:

[Mike Burgundy]

I'm hazarding that the MINUS 4.3V is a glitch, and it's really plus 4.3V, or more-or-less halfway between 0 and 9 right?
If you do measure negative voltage, something's definitely amiss.
If it's positive, the voltages to the opamp look okay, and you might have to probe. It's a really handy and easy tool, so make one.