12xxx Larry Ground

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axeman
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Re: 12xxx Larry Ground

Post by axeman » Fri Oct 19, 2012 4:03 pm

no BoogieEngineer install the Mustards I sent you.

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Re: 12xxx Larry Ground

Post by BoogieEngineer » Fri Oct 19, 2012 4:09 pm

axeman wrote:no BoogieEngineer install the Mustards I sent you.
Man I used them all up in my JTM45/100 build

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Re: 12xxx Larry Ground

Post by rgorke » Wed Oct 24, 2012 10:49 am

BoogieEngineer wrote:Please someone tell me what brand the cap circled in blue is!
To me it looks more like a Mylar dipped cap like these:

http://www.ebay.com/itm/2pc-New-Old-Sto ... 2323a341e7" onclick="window.open(this.href);return false;

I use them in V1b and the PI
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Re: 12xxx Larry Ground

Post by vanhalen5150 » Wed Oct 24, 2012 11:01 am

rgorke wrote:
BoogieEngineer wrote:Please someone tell me what brand the cap circled in blue is!
To me it looks more like a Mylar dipped cap like these:

http://www.ebay.com/itm/2pc-New-Old-Sto ... 2323a341e7" onclick="window.open(this.href);return false;

I use them in V1b and the PI
You could be right. I cant tell if thats a bump in the middle or an indentation.
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Re: 12xxx Larry Ground

Post by BoogieEngineer » Wed Oct 24, 2012 11:46 am

vhjunkie told me it's a CDE DME that sounds tight in the bass, open in the mid yet not harsh on highs (or so it seems from what I read about it on the forum). I will try them out for my next build

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Re: 12xxx Larry Ground

Post by emmjaydubya » Wed Oct 24, 2012 2:13 pm

Has anyone found the .0022uf 400v EL MENCOs at all? I see the 100v ones on ebay all the time but I'm not sure these are even usable.

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Re: 12xxx Larry Ground

Post by BoogieEngineer » Thu Oct 25, 2012 2:03 am

Regarding star grounding, what happens if you connect points 1,2,3,4 together? I've an amp that does that and it's quieter than my JTM45/100 with star grounding, but I'm not sure if the improvement is really due to points 1,2,3,4 connected.

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Re: 12xxx Larry Ground

Post by vanhalen5150 » Fri Oct 26, 2012 6:36 pm

I would doubt if that's the reason as well. Grounding schemes vary from amp to amp. 2 identical amps grounded the same way will still show different background noise.
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Re: 12xxx Larry Ground

Post by BoogieEngineer » Fri Oct 26, 2012 10:13 pm

Ok thanks. Another question, what point does the bias ground of the PT go to? Same as bias caps' ground, i.e #4?

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Re: 12xxx Larry Ground

Post by vanhalen5150 » Fri Oct 26, 2012 10:32 pm

Yup. Has 3.

#4 : PT bias ground, screens ground, bias caps ground.
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Re: 12xxx Larry Ground

Post by BoogieEngineer » Fri Oct 26, 2012 11:31 pm

vanhalen5150 wrote:Yup. Has 3.

#4 : PT bias ground, screens ground, bias caps ground.
Thanks a lot!

One more: my PT (ClassicTone C1998) has White and Greene for bias supply. Does it matter which one is grounded?

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Re: 12xxx Larry Ground

Post by clusterstudios » Sun Nov 11, 2012 4:29 pm

i take it that this grounding scheme requires extra drilling into the chassis?? right?? if so, what size drill bit?? are the centres approximate?? :scratch:
Joseph

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Re: 12xxx Larry Ground

Post by vanhalen5150 » Sun Nov 11, 2012 10:14 pm

clusterstudios wrote:i take it that this grounding scheme requires extra drilling into the chassis?? right?? if so, what size drill bit?? are the centres approximate?? :scratch:
I just use the bolts size that hold in your power tube sockets. Everything is really approximated. No real exact spacing. Some have suggested #5 be at least 1" from your PT.
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Re: 12xxx Larry Ground

Post by BoogieEngineer » Sun Nov 11, 2012 11:37 pm

I used the same size as the power tube socket's bolts too. That way it holds the ground lugs better than the smaller size that are for preamp sockets. I didn't know the 1" rule but looks like my #5 is a little more than 1" from the PT.

I remember Larry also saying that #5 should be away from 1,2,3,4. In my 2 builds, I put #5 close to V7 instead of in the line that 1,2,3,4 forms. Without pedals, those amp are so very quiet, even at large volume. Great grounding.

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Re: 12xxx Larry Ground

Post by vanhalen5150 » Mon Nov 12, 2012 6:56 am

If your using a PT bracket, your probably an 1" away already.
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