Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: mresistor on August 05, 2016, 01:14:33 pm

Title: AA964 vs AB763
Post by: mresistor on August 05, 2016, 01:14:33 pm

I've been looking at these two and comparing, but don't see much difference. What are the differences? If any.
Would be cool to use an AB763 turret board with the BV trem to build a real Vibrolux Rev amp.

Title: Re: AA964 vs AB763
Post by: HotBluePlates on August 05, 2016, 01:36:25 pm

I'm glad you specified "Vibrolux (http://el34world.com/charts/Schematics/files/fender/Fender_Vibrolux-Reverb-AA964-schematic.pdf)" because AA964 is also a blackface Princeton circuit number.

The Hoffman AB763 document (http://el34world.com/Hoffman/files/Hoffman_AB763_2.pdf) highlights most (all?) of the parts which vary. R45 will be 100Ω instead of 47Ω, and you'll have 6.8kΩ resistors instead of Mid pots. Other than that, they look identical with a cursory examination.

Title: Re: AA964 vs AB763
Post by: mresistor on August 05, 2016, 01:42:51 pm

So it should work just dandy...   :icon_biggrin:    Thanks HPB    I much prefer the BV trem...  (6G5?)   

Title: Re: AA964 vs AB763
Post by: HotBluePlates on August 05, 2016, 01:47:24 pm

Bias-vary trem: 6G16 Vibroverb.