Circuit Analysis Jim Kelley Amp

[Mark]

Did the FACS amp get built?

[FUCHSAUDIO]

Sure. It was an active model for some time. Fender style input channels and 4 x 6V6's running at a blazing 500 volts.
It also had an outboard attenuator that allowed a master volume of sorts.

[Mark]

Sure. It was an active model for some time. Fender style input channels and 4 x 6V6's running at a blazing 500 volts.
It also had an outboard attenuator that allowed a master volume of sorts.

That’s my thoughts exactly Andy. Even though it has roughly 8K on the screen grids, it’s a hell of a lot of voltage on 6V6’s.
Personally, I’m wary as it relies of valves being above spec and very good quality control. I just don’t see that happening these days.

I would understand people rewiring it to a more sturdy valve.

I understand that he was after more brightness and greater dynamics, but the cost to the valves and reliability troubles me.

[two tone]

Having 2 Jim Kellys, I can say ,it‘s not a problem with JJ‘s.One has 470v, the other about 460v on the plates.
High Plate Voltages are not so much problematic,High Screen Voltages can be.
These are great amps!

[FUCHSAUDIO]

Having 2 Jim Kellys, I can say ,it‘s not a problem with JJ‘s.One has 470v, the other about 460v on the plates.
High Plate Voltages are not so much problematic,High Screen Voltages can be.
These are great amps!

Jim Kelley is of the opinion that it's current that kills tubes, not voltage. I partially agree, but only if you roll back the screens a lot. In a Music Man, they used EL-34's and (later) 6L6's at 650 to 700 volts, but with the screens at half voltage and running about 20 ma a tube, and they lasted years. The current JJ 6V6's (rumored to be 6L6's in a smaller bottle) seem to hold up in the Kelly amps. There is a certain angry clarity of sound you can get from tubes getting beat-up at high voltage for sure....

[andrewx]

Hello all. I've looked at different JK schematics but I cannot find power amp node B. Node A is plates and screens, node C is the PI, node D is V1 and V2. Any help please.Thank you.

[dorrisant]

Hello all. I've looked at different JK schematics but I cannot find power amp node B. Node A is plates and screens, node C is the PI, node D is V1 and V2. Any help please.Thank you.

Welcome, Andrew!

The B node goes to the reverb driver...

https://ampgarage.com/forum/viewtopic.php?t=29580

Edit: I had already posted this on the previous page.

[andrewx]

Thanks Dorissant .