You thoughts on Plate Voltage?

[StratTone]

With the caution that I don't know exactly what you did when you "blackfaced" the amp, I'd just add that to get the amp to proportionally balance it's B+ you have to match the specs of the BF amp's dropping resistance in the cap pan. That is, along with removing the power tube grid caps & matching the PI resistance values to BF spec, and perhaps converting the amp to bias adjust vs bias balance (I do both), you need to match the cap pan dropping resistances to get things in balance.

If you're running the amp at today's line voltage (120 - 125vac) bear in mind the amp probably didn't see that kind of voltage when new. In fact, the old export amps had a selector switch for the various countries line voltage. The setting for North America was 117vac. Use that 117vdc as a guide when considering whether your amp's B+ is in the ballpark.

In general, when run at todays line voltages 50s, 60s & early 70s amps are going to run as much as 50vdc more B+ than shown on the schematics, and that's just not good. SS rectified amps are the most problematic. Although on tube rectified Fenders you can drop the B+ / plate voltage by selecting a different rated tube, this changes the amp's performance characteristics and does nothing about the higher heater voltages being generated.

There are two real fixes for this, either swap out the PT for a new one designed to operate at today's line voltages and render spec B+, or, use a variac, a buck transformer, etc. to drop the line voltage back to the 110 - 117vdc the amp was designed to see. You can make a simple buck transformer out of Radio Shack components, or spring for something like the Amp Preserver (do a Google) or the Weber Browner. One way or the other , if you get the amp to see spec internal voltages it will sound its best and tubes & components will last longer, too.

(All the above gleaned from experience, cursing, etc.....and, of course, JMHO!)

All great info you have there. I'm going to give the Amp preserver and Weber Browner a look. You info for sure gave me some ideas about builds I have coming up and some questions for the guys at MM. haha

As for what I have done, it is a complete Blackface with bias and all the nicknacks. I ended up changing to the doghouse resistors to BF and the voltage was way high. I put the 5U4 back in there and the voltage came back. Basically I had to decide if I liked the sound of the conversion better with the GZ34 and Silverface doghouse resistors, or the 5U4 with BF doghouse values. To my suprise I like the 5U4 setup. All and all it does sound great and a new set of speakers will make this puppy spank.

I will however be looking for a real BF Super in the future because I just don't think that I can get that sound out of this amp. (hopefully I'm wrong)

Of all my older Fenders. '67 Bassman, '67 Twin, '67 Bandmaster, '73 Super, The one that has the real deal blackface warmth/"I want to touch myselft" tone is the '67 twin.

I really believe it is the amps PT and OT setup that is the key with that amp. Sound just freaking rediculous good.