Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: dwp on June 23, 2010, 10:23:10 pm

Title: NOS 9 pin tube socket with ground round center question
Post by: dwp on June 23, 2010, 10:23:10 pm

Hey I have some NOS (Elco) shield type 9 pin socket bases, they have the center round ground pin that goes up through the middle of the base.

QUESTION: Is there any reason why or advantage to hooking it up to ground? (or something else?)

does it maybe help retain the chrystaline Lattice of the the tube enzyme to have the glass (Oops, I mean chrystal) in contact with a ground ring in the center of the pin array?

I've seen a few vintage amps, and have never seen one with this thing installed on a socket.

Am looking for some heavy bases to replace sockets in my Deluxe reverb, since I still have all the vintage steel shields, I don't have a good heavy base to compliment them, except the Elco's with the funky 10th pin.....
thanks in advance, dwp

Title: Re: NOS 9 pin tube socket with ground round center question
Post by: RicharD on June 23, 2010, 10:33:49 pm

That's a tie point that can be used for anything, not just ground.  For tubes like the EF86 where you have multiple often grounded thangs such as shields, suppressor, etc. it's a very convenient ground point.  I've seen them tied to B+ w/ plate resistors hanging off.

Title: Re: NOS 9 pin tube socket with ground round center question
Post by: sluckey on June 23, 2010, 10:50:21 pm

They were a nice feature for video, IF, and RF circuits. They just get in my way for guitar work, so I remove them.