Express Tone Stack Grounding

[DaveWell]

I Asking Why the Tone-Stack are grounding like this:

3X 40UF
2x 20uf
And the 3rd 20uf are separately

But.. All at the same ground point...

And Why All the way to the front where B+ are...

Why not Grounding on the back , on a PW Transfo bolt?

[RJ Guitars]

It's been argued back and forth a bunch... Most savvy builders will tell you that the original Wreck grounding scheme could have been done better. On the other hand most folks who recognize great tone and legendary amp history will tell you that it's foolish to 2nd guess KF.

In this case, separating the grounds keeps noise from the power and PI sections from bleeding into the preamp stages. This is a good thing to do and also where some folks will tell you it could have been done better in the Wreck amps. I think Randall Aiken has a really grounding scheme that isolates each section of the amp from the others.

For the most part I've found that there is not any real issue with the original grounding scheme whether it's ideal or not and it has not caused me grief in my builds... nor have i held to it perfectly.

YMMV

[DaveWell]

I totally agree that separate tone stack grounding help reduce the noise.

I take this example from EL34 site.

[hans-jörg]

Hi,
I agree with this grounding schem, but the power cord green/yellow wire should be always separate grounded, close to inlet and very proper. This one should be always the only and last one which lost his contact to chassis. Your life can hang on this connection.
Ym2ct

Hans-Jörg

[rooster]

I agree with RJ's experience, it's hard to ground an Express such that it makes added noise. That said, I do think Hans-Jorg is correct about the AC ground, place it on it's own ground and as close to the cable/chassis entry as possible, away from the other grounds.

I will also add that I think the AC filament ground should be by itself, too, somewhat close to the 100/120/220 AC ground and away from the DC filter ground paths.

Your build is clean looking, Dave, a nice job, but I posted something about your cap choice on another thread. If you want to improve the sound of your build at this point, start with the coupling caps.