Larry's star grounding for a JTM 45

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MattJ
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Larry's star grounding for a JTM 45

Post by MattJ » Wed Jan 11, 2017 1:41 pm

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.

danman
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Re: Larry's star grounding for a JTM 45

Post by danman » Wed Jan 11, 2017 4:56 pm

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.

MattJ
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Re: Larry's star grounding for a JTM 45

Post by MattJ » Wed Jan 11, 2017 5:23 pm

Thanks Dan!
I certainly will!

- Matt J.

Wattever
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Re: Larry's star grounding for a JTM 45

Post by Wattever » Wed Jan 11, 2017 8:44 pm

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

MattJ
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Re: Larry's star grounding for a JTM 45

Post by MattJ » Wed Jan 11, 2017 8:50 pm

Is there anyway you could PM it to me?

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Re: Larry's star grounding for a JTM 45

Post by Wattever » Wed Jan 11, 2017 9:01 pm

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

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Re: Larry's star grounding for a JTM 45

Post by ValveStorm » Thu Jan 19, 2017 9:49 pm

ValveStorm.comParts, parts parts!

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Re: Larry's star grounding for a JTM 45

Post by Roe » Sat Jan 21, 2017 3:24 pm

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
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Re: Larry's star grounding for a JTM 45

Post by wdelaney72 » Wed Feb 01, 2017 12:21 pm

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.
Walter

"There's no great thing in being a soloist. I think the hardest thing is to play together with a lot of people, and do it right." - Angus Young, 1984

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