Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Colas LeGrippa on January 24, 2013, 01:33:41 pm

Title: PUSH-PULL, no cathode follower ?
Post by: Colas LeGrippa on January 24, 2013, 01:33:41 pm

I am modifying a  50 w amplifier with no tone stack. I was wandering if I could skip the cathode follower and send the signal straight to the PI, from the preamp tube. Would that be a heavy load on the preamp tube ( s ) ?  I couldn't find no schem of PP amp with no CF.

Thanx

Colas

Title: Re: PUSH-PULL, no cathode follower ?
Post by: Willabe on January 24, 2013, 01:49:01 pm

Quote from: Colas LeGrippa on January 24, 2013, 01:33:41 pm

I couldn't find no schem of PP amp with no CF.

Fender BF AB763 (and silver face models) TS has no CF. It's plate driven.

You can feed the PI with a coupling cap from the plate of the preamp tube, but it might not have enough drive signal. I think you need at least 2 triode gain stages.


             Brad     :think1:

Title: Re: PUSH-PULL, no cathode follower ?
Post by: archaos on January 24, 2013, 02:03:03 pm

Quote

I couldn't find no schem of PP amp with no CF.

Check the AC30 normal channel schematic (no tone stack) & you're done... :icon_biggrin:

Title: Re: PUSH-PULL, no cathode follower ?
Post by: Colas LeGrippa on January 24, 2013, 02:27:58 pm

Quote

You can feed the PI with a coupling cap from the plate of the preamp tube, but it might not have enough drive signal. I think you need at least 2 triode gain stages.

PP amps require more signal voltage than a SE ( like the Fender Champ ? )

Title: Re: PUSH-PULL, no cathode follower ?
Post by: DummyLoad on January 24, 2013, 02:30:43 pm

yes, you can. will you have enough drive swing? that's another question and requires schematic with telemetry to answer with reasonable accuracy.

--DL