Grounding for Presence control

[?Mark]

DON'T ground to pot or other points at or near Presence control.
Just take all ground(s) from the Presence control back to 1ST CAP CAN GND POINT
and gnd there.

Surprised me, after looking at the way other pro builders (RP) did this and I will ALWAYS
do it this way now. Last bit of noise is GONE, even when Vol. maxed!

[JCarno]

For what amp is this recommended? 2204?

[?Mark]

I found this on a no longer available
custom build RP. and it's the presence
gnd point on others of the same maker.

model: Lloyd Jones Savoy/Blackloop

I tried it in my JTM 45 1st,
and it works very well indeed.

[neikeel]

We have been recommending it here for some years along with other parts of the grounding schemes (Larry's or SDM's).

[Doug H]

run the presence, and speaker ground reference, all the way back to the 1st ground point?

[JCarno]

DON'T ground to pot or other points at or near Presence control.
Just take all ground(s) from the control back to 1ST CAP CAN GND POINT
and gnd there.

Surprised me, after looking at other pro builds did this and will ALWAYS
do it this way now. Last bit of noise is gone, even when Vol. maxed!

Can you post a pic or diagram please? I'm not quite getting what you're saying.
And is it worth it to do it on 2204(4104)?
Does it change the "tone" of the amp at all?
I'm pretty happy with the tone although it is a little noisy(hiss,hum,buzz) while not playing it. But you don't here any of that once you start playing.
Thanks for any further info you can provide, even if it's a link to another thread.

EDIT: Anyone can chime in here. I just quoted the OP because thats what my questions are based on. Thanks!

[danman]

Do a search here on the forum for "Larry Grounding" scheme and you will find what Neikeel is referring too. It's a great scheme that produces a very quiet amp and does not change the tone in any way. It works with all of the various Marshall circuits or any circuit for that matter.

[neikeel]

Yes, I was also going to link to SDM's alternative grounding scheme that I typically use when I do not want to drill any extra holes, but the links form his temp Google drive are not working for me at the moment, not sure if it is a server issue?

[JCarno]

Sheesh, I just googled "Larry Grounding" and there's tons of pics and info, mostly leading back to this site.
Thanks!

[Doug H]

but the Larry grounding scheme doesn't put the presence pot back to the first filter cap. regardless of whether that means the v1 or the mains.

[neikeel]

The correct point is the PI filter cap ground (some might interpret that as the can in the corner on a 100w amp?)