Volume bleed through on OD pedal

[Bucksears]

I'm working on a clone of a Tube Zone and I was checking some voltages with my multimeter the other day; now I have some volume bleeding through even when the volume is all the way down. When I was doing the testing, I had a 9V AC power supply connected and a plug in the input jack.
It's more noticeable when the gain is maxed. It's got that gated/splatty sound, but gets more normalizes as you turn up the volume.

Anyone else ever experience this phenomenon? Is it some excess voltage somewhere?

[nocentelli]

volume bleeding through even when the volume is all the way down.

That says to me that the volume pot isn't properly grounded at lug1 - When at minimum, the output will be grounded and silent no matter how high the gain of the circuit preceding it.

[Bucksears]

Thanks - my only argument with that is the fact that my manufactured/real Tube Zone is doing the same thing now, too; that one has the volume control mounted to the board.

[petemoore]

  Having exp'd countless electronic phenomenon...probably "yes I've exp'd this".
  The signal goes in the 'top' of the wafer, and out the wiper...but if the wiper is grounded all signal would be held at Gnd. potential, and very little electron 'movement' gets past a ground shunt, it should sound like 'off' completely.
  Check to see the volume pot lug connects to ground, pots can act funny as any other electromechanical device, bleed through'd happen if the pot wiper/groundlug don't connect when pot is adjusted ATWay CCW.
  Not that this is the only way such phenomenon could be fascilitated...

[Bucksears]

Last night I checked continuity from the wiper (lug2) & ground (lug1); it tested positive with the volume control at minimum. FWIW, the volume control isn't at the end of the circuit; it goes through another buffer stage and with the 'presence' trimpot before it hits the footswitch/output.