12xxx Larry Ground

Moderator: VelvetGeorge

Post Reply
User avatar
axeman
Senior Member
Posts: 2455
Joined: Wed Apr 02, 2008 1:21 pm
Just the numbers in order: 7
Location: Los Angeles
Contact:

Re: 12xxx Larry Ground

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

no BoogieEngineer install the Mustards I sent you.

BoogieEngineer
Senior Member
Posts: 227
Joined: Sat Jun 30, 2012 1:53 am
Just the numbers in order: 13492
Location: La Jolla, CA

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

User avatar
rgorke
Senior Member
Posts: 4509
Joined: Fri Feb 08, 2008 11:37 am
Just the numbers in order: 13492
Location: Drought Ravaged SoCal

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
"If you make a mistake, do it twice and smile and let people think you meant it." Jan Van Halen.

User avatar
vanhalen5150
Senior Member
Posts: 7307
Joined: Wed Sep 10, 2008 3:13 pm
Just the numbers in order: 7
Location: Halifax, Canada

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.
12000 Metro Kit

BoogieEngineer
Senior Member
Posts: 227
Joined: Sat Jun 30, 2012 1:53 am
Just the numbers in order: 13492
Location: La Jolla, CA

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

emmjaydubya
Senior Member
Posts: 376
Joined: Tue Mar 01, 2011 6:51 pm
Just the numbers in order: 7
Location: Austin

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.

BoogieEngineer
Senior Member
Posts: 227
Joined: Sat Jun 30, 2012 1:53 am
Just the numbers in order: 13492
Location: La Jolla, CA

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.

User avatar
vanhalen5150
Senior Member
Posts: 7307
Joined: Wed Sep 10, 2008 3:13 pm
Just the numbers in order: 7
Location: Halifax, Canada

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.
12000 Metro Kit

BoogieEngineer
Senior Member
Posts: 227
Joined: Sat Jun 30, 2012 1:53 am
Just the numbers in order: 13492
Location: La Jolla, CA

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?

User avatar
vanhalen5150
Senior Member
Posts: 7307
Joined: Wed Sep 10, 2008 3:13 pm
Just the numbers in order: 7
Location: Halifax, Canada

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.
12000 Metro Kit

BoogieEngineer
Senior Member
Posts: 227
Joined: Sat Jun 30, 2012 1:53 am
Just the numbers in order: 13492
Location: La Jolla, CA

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?

User avatar
clusterstudios
Senior Member
Posts: 93
Joined: Sun Feb 24, 2008 10:06 pm
Location: Toronto, Canada
Contact:

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

User avatar
vanhalen5150
Senior Member
Posts: 7307
Joined: Wed Sep 10, 2008 3:13 pm
Just the numbers in order: 7
Location: Halifax, Canada

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.
12000 Metro Kit

BoogieEngineer
Senior Member
Posts: 227
Joined: Sat Jun 30, 2012 1:53 am
Just the numbers in order: 13492
Location: La Jolla, CA

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.

User avatar
vanhalen5150
Senior Member
Posts: 7307
Joined: Wed Sep 10, 2008 3:13 pm
Just the numbers in order: 7
Location: Halifax, Canada

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.
12000 Metro Kit

Post Reply