Tweed Bassman 6V6s - transformers options?

[Arry]

Hi there, my first post here.

I own a Fender Tweed Bassman reissue amp, which, over the years, I modded with a Hoffman board, Mercury Magnetics Transformers and new speakers.
I like the amp a lot, it's got a great, fat tone, but very loud.
In order to reduce the volume a little bit, and to get an early breakup (for the music I play, I rarely, if ever, need a totally clean sound) I decided to experiment and I installed 6V6 tubes along with a 5Y3 rectifier, checked the bias and disconnected two of the 4 speakers in order to get a 4 ohm load.
Right now I have a plate voltage of around 430v, but the tubes don't seem to mind so far.
I have to say I really like the tone of the 6V6 tubes, they're less "hi-fi" and "flat sounding" than the 5881s I had before, or maybe I like the reduced efficiency of just two 10" speakers compared to the stock 4x10 configuration.
Anyway, the amp definitely breaks up sooner but we're still too loud for most gigs. I was thinking about changing the power transformer to lower the voltage (I would aim at 320-350v max plate voltage) and get a smaller output transformer to get some more compression.

What transformer models would you suggest I get? So far I've only used Mercury Transformers, which I like, but I'm happy to try Classic Tone, Hammond transformers or other brands as long as they sound good.

I hope you can help me out with this; so far, the advice I got more frequently was to sell the Bassman and get something smaller. Makes total sense, but I already own a 5E3 (which I play 90% of the time). I don't want to sell the Bassman, what I'm after is a 15-20 watt version of the 5F6 circuit.

[shooter]

sell the Bassman

short of that, you probably need to get plate V to around <350.  look into zener CT PS.
try doing cathode biasing on the 6v6's, swap V1 to an AU.
try low efficient speakers, <90db

I have a 16-20w el34 that everyone that plugs in "thinks" is 40W  so you may not get there from here

[tubenit]

A transformer with 300-0-300 and 140 ma would work well for 6V6 or 5881/6L6.  IF you are going to use a small chassis, then a stand up PT might
be useful to you?  Guesstimates below:

300 x 5Y3GT  (1.1) =  330v
300 x 5V4      (1.2) =  360v
300 x GZ34    (1.3) =  390v
300 x solid state plug-in (1.4) = 420v

IF you wanted to make it cathode biased and used a 250 ohm to 330 ohm range resistor, then you could simply swap tubes without re-biasing.  IF you used a 100 uf/110v cathode cap, it would make it sound a little more like fixed biased then a 22uf cap would. 

You'd probably have about 14-17 watts with 6V6 and about 17-23 watts with 5881's  depending on the voltage and rectifier.

This is the approach I use for both my amps and I like the tonal options going this route.

with respect, Tubenit

[Arry]

Thank you Shooter and Tubenit for your replies.

A transformer with 300-0-300 and 140 ma would work well for 6V6 or 5881/6L6.  IF you are going to use a small chassis, then a stand up PT might
be useful to you? 

For now I think I'll stay with the stock fixed bias but thank you for the explanation.
I'm using the stock Fender chassis: do you think a Classic Tone 40-18028 (Deluxe Reverb PT) might work? It's got a 300V-0-300V option and 120ma.
Also, I would like to install a smaller OT than the stock transformer I have right now.
Would a tweed deluxe output transformer work (8K to 4ohm)?

[drgonzonm]

You can always cheat to lower the power a little more, by running the speakers in series. 

I believe you can decrease the cathode-plate differential, by using mosfets. 

[drew]

You might try experimenting with a MOSFET B+ reducer - http://ampgarage.com/forum/viewtopic.php?t=27035 - to see if bringing the voltage down to the level you're talking about will give you the result you're looking for.