View Full Version : Biasing amps with ultra linear transformers
04-08-2008, 11:41 AM
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
04-08-2008, 01:09 PM
04-08-2008, 01:45 PM
I agree with OTM. Mind, aren't most UL amplifiers biased pretty hot? I may be thinking hi-fi here more than MI.
04-08-2008, 02:40 PM
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.
04-08-2008, 05:24 PM
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