Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: six_eight on November 08, 2012, 12:55:35 pm
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The AA1164 is supposedly 12 watts, but the AB763 is touted as being 20watts. Where are the extra 6 watts coming from? It seems like the only real difference between the two (aside from the speaker sizes and the deluxe's second channel) is the phase inverter. Does phase inverter really make that much of a difference or is it something else?
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The output transformer is smaller on the Princeton and bigger on the Deluxe
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Output transformer size and impedence are different. The Voltages and power sections are subtly different (note the double 18k resistors in the Princetons power section and the differences of connection between the Deluxe & the Princeton). One has a choke... one doesn't. Different rectifiers ta boot.
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Don't know if they are really 12w vs 20w. I only know everyone has repeated those numbers long enough for it to be "gospel".
I used to own a BF Princeton Reverb; the BF Deluxe Reverb is indeed louder, but not by a lot. Of course, it also uses that 12" speaker instead of a 10" and has a larger cabinet. And different power and output transformers, different phase inverter.
But I would not be surprised if Fender marked it as more-power in the catalog, even if it really wasn't. It was the next model up from the Princeton, so they're gonna charge you more. You already get a channel extra that the Princeton doesn't have. The bigger speaker, too. But just in case that doesn't seem like enough to justify the price gap, why not claim a few extra watts?
I looked up the 1964 Fender catalog, and squinting at the pics I found, no power levels are claimed, although they do note the Princeton Reverb is "Perfect for student and home use!"
Maybe they needed a bigger selling point by 1968. Interesting they bother claiming peak power (I guess the power wars had started by that point).
(http://www.vintageguitarandbass.com/graphics/fender68p34.jpg)