Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Beezerboy on March 31, 2026, 03:18:19 am
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looking at Hoffman ab763 and do not see the node voltages. got any input?
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Someone probably knows better about this than I do (please chime in if I've got this wrong), but I think the schematics on the site are guidelines for many different builds. The AB763 covers several fender models that have virtually the same topography across builds of various sizes and output wattage. You would use transformers, tubes, and speakers matched to your needs. Changing transformers and tubes will change all of the voltages, so better to leave the schematic node voltages blank. You'd probably need to guestimate using the fender schematics that most closely match your build. This calculator is pretty handy too for plate voltages: https://thesubjectmatter.com/calcptcurrent.html Cheers
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looking at Hoffman ab763 and do not see the node voltages. ...
Almost all of the mid-1960s Fender amps were "AB763." But they each had different voltages.
And that's one reason the Hoffman AB763 layout doesn't have node voltages. FWIW, you may have several resistor-values to change to exactly match a specific AB763 amp-model.