A quiet Tremolux

[Bobcube]

About 30 years ago I found myself in a recording session, playing through a blonde Tremolux. The sound was just superb, better than anything I'd used previously.
Fast forward about 15 years, and I found a similar unit for sale, bought it, and carried it off, only to be seriously disappointed. It just lacked tone!
Since then I've periodically replaced bits, trying to regain what I heard all those years ago.
The retro-fitted Fane 12"'s have been swapped for a sucession of 12" and 10" speakers - currently I have a couple of Celestion 10"s in there.
I replaced the mains transformer and silicon rectifier, reverting to a GZ34.
All the major caps have been replaced. It's been revalved throughout

The amp is still desperately quiet, subjectively about 15 watts, compared to a Peavey Classic 30, Musicman 65 etc. (how come both the Tremolux and Musicman have 2 x 6L6's yet one is rated at 65 watt, the other 30 watt?).
The Tremolux tone remains thin - no middle, no sparkle.
Short of replacing the Tolex, I'm at a loss what else to do.
Any suggestions please?

[loudthud]

IIRC there was one version of the Tremolux that used EL84's. Could that have been the one that had the magic?

The original metal 6L6 (1930's?) is a far cry from what we see today, the 6L6GC (early 60's?). Along the way, the maximum ratings of the tubes increased. Early Fender designs tended to be a little conservitive, but over the years power crept up as the ratings of the tubes increased. Musicman amps tended to operate tubes beyond their maximum ratings but didn't compromise reliability too much. They were designed during the power wars of the early 70's. Fender amps usually were tightly focused on a particular feature-power-price point that did not squeeze every last watt out of the power tubes. In the Blackface era, almost every amp had 2 6L6GC's but power varied from 35ish to 50 watts. So I guess the short answer is that power depends on many factors beyond what tubes are used.

What year is your Tremolux and does it have a bias adjustment?

[Old Tele man]

...as I recall, the MusicMan amps run a lot higher Plate Voltages (+710Vdc!) and use "unique" cathode-modulation.

[Bobcube]

It's a '64 AA763 circuit.

I've fiddled with the bias, and it ain't that!
I was wondering whether one or other of the carbon resistors has drifted? Trouble is, if I start replacing these, there'll be little left that's original. I fear any remaining Mojo will evaporate!

[loudthud]

A good way to narrow down things is checking voltages against one of Fender's layout diagrams. These days, you can expect voltages to be 5-10% higher than the numbers on the diagram. Here's a link to one such diagram:

http://www.el34world.com/charts/Sche...OLUX_AA763.pdf