Princeton / Champ never seems to break up like "Layla"

Strum/pick harder? Humbuckers/P90s?

Truthfully, this is the first time I can remember reading someone complaining about tweed champ headroom. I first figured it was for BF/SF, of which voltage could be part of that equation. But tweeds are generally not an issue for breakup.

Use less efficient speaker and/or an attenuator, perhaps? Maybe you can tweak anode or screen resistance? Just spitballing.

To me, any close mic'ed amp signal is gonna sound more compressed and distorted than live in the room. So definitely experiment with placement, too.

 

Mind sharing more info? How about some photos? Complete voltage chart? Is everything stock? 6v6 bias resistor 470 ohms? bypass caps in place? stock NFB circuit?

 

This is probably no help as I've never really owned either of those amps but I did remember reading that I think Clapton used to turn the Princeton all the way up and the treble all the way up

 

What kind of speaker do you have in it?

 

Hmmm..... never bonded with my Champs because they were always too much breakup!

 

The SS rectifier is a big part of the problem, if not all of it. Stick a 5y3 in there, be sure you have a bypass cap on V1, and a 12ax7 in the slot. If that doesn't do it, I'd suggest a circuit issue.

 

Someone will be along shortly to contend that a tube rectifier won't matter in a Champ, (because single ended amps don't sag?).
I don't know enough to offer an argument, but I'm here for it .

 

It will surely drop the voltage more than a solid state rectifier

 

Sag may not change. But voltage can. SS will run higher voltage, which would have to be compensated down stream in the circuit. I don't know enough to say. But I think 330-0-330v is pretty standard for a tube rectified champ or princeton. That would yield pretty high plate voltages with SS rec in an unmodded circuit.

OP, what's the bias/dissipation at 500ohms? If the 6V6 is well over 100% dissipation, it's gonna break up a lot less.

 

Not to be mixed with Jack Daniels!

 

I'm not going to get into it about it for argument's sake on the "sag" issue, but there's night & day difference in the tone and response between a 5y3 and GZ34 in the one's I've built. Way more headroom and punch with the GZ34. I've posted it several times, but the guy who ended up with this 5f2a has a GZ34 and C10Q and uses it as a clean pedal platform with his Les Paul because it has the headroom to do it. Leaves his '68 Custom Vibrolux at home most of the time now. I don't have a GZ34 demo with it, but this is a Nashville Tele and 5y3 for an example of something that is the exact opposite of what I just described. I know the voltage is higher, but if you swap the 275v secondary for the 325v option and use a 5y3, the voltage is dang near what the 275v gets with the GZ34, and 375v B+ both ways just does not sound the same. The 5y3 is recognizable in tone and headroom at 340v or 380v in comparison.

Hammond 290AX with the 275v secondary will hit dead on 340v B+ with a JJ 5y3, per the vintage 5y3 layout diagram.

 

Hmm. Clean headroom is something my 57 Champ does NOT have. It starts breaking up around 3.5-4 and goes from pretty gnarly to flat out nasty between 7 and 12.

 

maybe he was using a rangemaster. it's not like we'll ever know the real signal path.