Express volume and tonestack issues

[peckjed]

Mark - I actually just ordered all new pots for the volume/tone and presence knobs. I intend on being much more careful with the new pots.

Is there a purpose to soldering to the back of a pot that does not have the ground lug attached to buss bar? It looks as if the only ground lugs connected are the volume, middle and presence.

[M Fowler]

Actually the soldering to back of pots was for pot anti-rotation reasons and served as ground point.

Those .390 grounding tabs are for pots like PEC that are difficult to solder to the backs without doing a bunch of prep or any 3/8 thread pot.

Also, heat can cause problems internally to the pots so people do not like soldering to the backs. Turn pot full clock wise before soldering so that the tracing doesn't get wrecked during soldering.

Enjoy

[peckjed]

I just wanted to update all those who helped. I installed all new potentiometers and everything seems to be functioning correctly now. The volume knob doesn't eliminate ALL the volume when turned to 0, sonthere is some bleed. But that seems normal from my understanding. Now I just need to figure out how to quiet this inherently noisy beast down! Thank you everyone for all the help!!

[peckjed]

So I don't think this problem is alleviated. when the master volume is full open the volume leak is pretty loud. My tech suggested installing a 33k grid resistor on pin 7 of v1 and that did not help.

I've noticed in other builds, grid stoppers are used elsewhere in the preamp tubes... would this possibly help? If so, suggestions on where and values would be very helpful!

[jelle]

Steel chassis with a coating. That is not a proper Express chassis material.

Did you remove the coating down to the bare steel with a dremel before adding pots, and other chassis ground connections?

jelle

www.welagen.com

[peckjed]

Steel chassis with a coating. That is not a proper Express chassis material.

Did you remove the coating down to the bare steel with a dremel before adding pots, and other chassis ground connections?

jelle

www.welagen.com

that's a good point... something I did not do, yet. Looks like I'll be picking up a dremel tomorrow.

[peckjed]

Steel chassis with a coating. That is not a proper Express chassis material.

Did you remove the coating down to the bare steel with a dremel before adding pots, and other chassis ground connections?

jelle

www.welagen.com

that's a good point... something I did not do, yet. Looks like I'll be picking up a dremel tomorrow.

So I cleared out the coating behind the pots/ground points and the issue is still happening. I noticed in the Ceriatone layout there is an 820 grid resistor on pin 2 of V1... is it possible that could help the volume bleed?