Volume pot doesnt completely turn off

[ACDCG400]

hey guys! i built a deluxe and all works as it should, but the volume pot on zero doesnt actually turn the sound completely off. im quite lost as to why, i replaced the pot, the shielded wir that feeds V1b, and theres no lack of volume. it just doesnt completely turn off -______- any ideas guys?

Cheers!

[sluckey]

Could be a defective pot. Or the ground to the pot may not be a good ground.

[ACDCG400]

Thanks Sluckley, ill take a look!

[ACDCG400]

ok so its not the pot or the ground. i replaced the volume pot, moved the ground. then realized that it does it even if the grid of v1b isnt connected. i disconnected the mid pot ground to have the ts bypassed and it still does it. i bypassed the stage after reverb recovery and it does it (albeit faintly), i disconnected the tank and it does it. that only leaves me with the first stage components, no? i isolated the input jack from ground as well and it still does it.

any thoughts? 

[sluckey]

When you said "i built a deluxe" I had assumed you built a Fender Deluxe 5E3. Sorry 'bout that. Now you're talking about a mid pot so I know its not a stock Fender Deluxe Reverb either. What exactly do you have? Whose drawings are you using? Can you post a schematic and layout?

then realized that it does it even if the grid of v1b isnt connected.

I'm guessing that the wiper of the vol pot normally connects directly to the grid of v1b like an AB763 amp? If so, leaving that grid open is not a good condition. Can you kill the volume if you put a jumper from chassis ground directly to the grid of v1b?

[ACDCG400]

Ill check when I get home, I'm using the hoffman one channel ab763 layout.

[tubeswell]

filter cap for the pre-amp node not grounded properly (causing the signal to get bounced through the power rail into the other pre-amp stages) methinks

[ACDCG400]

I moved and triple checked the filter cap grounds and grounded that grid and still i hear it :( any other suggestions? its not affected by the tone controls either 

[ACDCG400]

i got rid of it!!! i havent a clue what it was though. most likely a bad ground  thanks guys!!!

[tubeswell]

i got rid of it!!! i havent a clue what it was though. most likely a bad ground  thanks guys!!!

If the pre-amp filter cap isn't grounded then the pre-amp dropper resistor turns into another load resistor for the preamp stages, and the signal gets coupled into all the stages that are not decoupled in the power supply. If this happens in a DR, this means that even if a vol pot is in perfect working order, turning it down won't turn the vol down because the signal at V1a will get into V1b through the undecoupled supply resistor for the pre-amp node. Not saying this is what happened in your amp - just guessing from a remote desktop.