Biasing amps with ultra linear transformers

[HarryB]

I'm working on a Fender Bassman 135, which has an ultra linear transformer. I got to wondering how to set up the bias for this type of an amp. Can the 60/70% of max power guideline still be followed? Thanks.

[Old Tele man]

...yes.

[donnyjaguar]

I agree with OTM. Mind, aren't most UL amplifiers biased pretty hot? I may be thinking hi-fi here more than MI.

[EarlTX]

Right!..it's still a Class AB1 amp. Since the circuit has local NFB via the screen grids/ul taps, biasing it "hot" won't have much effect, so go for tube life.

[HarryB]

Thanks!