overdrive signal/op amp problems. popular build!!

[nate77]

I'm working on a version of a popular overdrive circuit that may or may not have been boosted by the lovepedal crew.......
Anywho, all of that aside, I've managed to debug all of my silly little mistakes and oversights but 1... I've followed the live signal through with an audio probe and what I'm getting is the full desired signal, overdrive and all through the first half of the op amp (tried both 4559 and 4558), as it comes out of pin 1 the signal goes through a potentiometer and a 1k5 resistor then into pin 5 of the op amp and that's the last of the intact signal. As soon as I put the probe on pin 6 or 7 the signal seems to have picked up some volume and aggressive motor boating. from there, there isn't much left to the circuit, it goes right into the volume pot, through a 1uf resistor and then to output. Unfortunately mu photobucket account is weirding  out on me and I'm also having trouble linking the site with the layout and schematic. Any help would be very much appreciated. In this small circuit where  can the signal go to get this uncool??  As always, thanks in advance for any help. Thanks for looking!

[Quackzed]

does it have a reference to vref, to 4.5v ? like a 10k or is the potentiometer referenced to ground?

[nate77]

It looks like it comes from the "left" side of the op amp (pins 1, 2 and 3), into a treble pot, through a 1k5 resistor then into pin 5 of the op amp, then the voltage is divided through a pair of 3k3 resistors, 1 to vref and 1 through a 1uf cap then into a volume pot (wired to the board, ground and output). I'm trying to dig up a link without pasting the circuit name openly as it is still in production. I've got the real deal coming in a few weeks but have been a little antsy and needed a preview of what I had coming. If I can find a cleverly titled address I'll copy a link as soon as I can. I'm very anxious to figure this little beast out. Thanks!!

[nocentelli]

You should have roughly vref on pin 6 (inverting input) from a 3k3 from vref, and also on pin 7 (linked by another 3k3 from pin 6) - you should also have vref on pin 5 (non-inverting input) because it is DC coupled to the output of the first opamp output by the 1k5 and 50k treble pot: Pin 5 should also have a 10n to ground: Check this is actually 10n, not 100n or 1000n (i.e. 1UF) because that might turn your "treble bleed to ground" control into an "everything bleed to ground" control and would explain the loss of signal.

[nate77]

Thanks man. I'll be home from work shortly and I'll measure those pins and see where I'm at. The signal issue seems to develop somewhere between pin 7 and the subsequent 3k3, but my technical knowledge is clearly lacking. I'm sure that the 10n cap is correct as I went over my layout a billion or so times. I appreciate the advice and help. I'll post back after I measure the op amp pins and get a set of fresh eyes on this thing. It's always the easy ones that screw me up!