Metropoulos Forum

Hello Everyone!

I've been planning on building a JTM 45 for quite some time now. I've been slowly putting together as much information as possible before I start gathering pieces for my build. I plan on buying most of my parts from the ValveStorm store.

One question I do have that I was hoping someone could help me with is grounding scheme for a JTM45 by Larry that I see frequently mentioned. Links or image downloads that I come across to this information no longer seem to work. Would anyone mind posting a copy of this scheme? I would like to consider using it on my JTM 45 because I like to make an amp as low noise as possible!!

Thanks!
- Matt J.

Unfortunately, a lot of the layouts and other info were lost when the forum changed over last year. Hopefully one of the members have saved a copy that they could post. You may also want to ask over in the builds and restoration subforum so that more members will see your request.

Thanks Dan!
I certainly will!

- Matt J.

I have it, but I can't get it to post.

Is there anyway you could PM it to me?

PM me an E-mail address and I'll send it that way.

great, except the screens should be together with the bias circuit, not the mains, IF if remember correctly.

EDIT: you need to compromise with those dual filter caps with shared ground. So if the mains and screens are the same cap, they will also have the same ground in that case

Looks like you guys have this covered already. Just as a note, here's what I use based off of Larry's advice.

4 lugs attached to one of the choke mounting bolts:
Input jack
Pre-amp Cathode bypass caps
Pre-amp Filter cap
Pot Buss

3 lugs attached to PI cap mounting bolt closest to chassis:
Screens
PI
Bias

3 lugs attached to PI cap mounting bolt closest to front of chassis:
Mains caps
Heaters / Filament Center tap
PT Center tap (N/a for 50w or JTM 450

Output Speaker jacks get their own grounding lug
Input power voltage gets own grounding lug.