Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: RickRS on June 01, 2013, 06:33:38 pm
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My Fender Pro Reverb's sticker ID it as a Vibrolux Reverb AA86, which isn't in the schematics.
What the chance that Bassman AA864 would be the same, minus the reverb section, schematic-wise?
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Obviously it's missing at least one digit.
Aside from reverb, the only differences I see in the AB763 Pro (http://ampwares.com/schematics/pro_aa763.pdf) and the AA165 Pro Reverb (http://www.el34world.com/charts/Schematics/files/fender/PRO_REVERB_AA165.pdf) are the number of speakers, the voltage rating/arrangement of the first filter caps, and the value one cap in the tone stack.
I'd suggest comparing what's in your amp to these items to determine the appropriate schematic. The blackface Pro isn't an amp that had much variation.
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That's AA864, as in the title.
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Looks like I also couldn't figure out if we're talking about a Vibrolux or a Pro Reverb.
Same general statement applies. The blackface circuits are largely identical for the 6L6 amps, except for number of output tubes and size/number of speakers. Also changed with number of output tubes is the shunt feedback resistor value. In the earliest blackface amps, a 0.033uF cap was used in the tone stack, which is later changed to the 0.047uF.
Do not, however, use the Bassman as a guide. The bass channel is very different and really doesn't match anything else in the Fender lineup. Pick a different blackface 6L6 Fender and compare your amp to its circuit.
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Looks like I also couldn't figure out if we're talking about a Vibrolux or a Pro Reverb.
It's a Pro Reverb. Two 12 inches in the cabinet, Pro Reverb right on the front. The paper label inside the cabinet said "Vibrolux Reverb AA864". I believe the Pro and the Vibrolux both output 40 watts at that time, with the difference being the speaker configuration: twin 12" for the Pro Reverb, twin 10" for the Vibrolux Reverb.
If there's no schematic for the Pro Reverb AA864 I was just going to pick one of the other Pro Reverb as a starting point and measure and determine what's in the circuit myself.
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It's a Pro Reverb. Two 12 inches in the cabinet, Pro Reverb right on the front. The paper label inside the cabinet said "Vibrolux Reverb AA864". ...
Oh... now I get it!
I don't know this for sure, but the Fender Amp Field Guide says the Pro Reverb (http://ampwares.com/amplifiers/fender-blackface-pro-reverb/) cabinet is 19.5"x26.5" while the Vibrolux Reverb (http://ampwares.com/amplifiers/fender-blackface-vibrolux-reverb/) cabinet is 18"x25".
So someone may have taken a Vibrolux and cut bigger holes in the baffle board (or otherwise assembled a Pro Reverb after the fact), or maybe Fender just used the wrong label in the cabinet. The cab dimensions should hopefully answer which is the case.
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So someone may have taken a Vibrolux and cut bigger holes in the baffle board (or otherwise assembled a Pro Reverb after the fact), or maybe Fender just used the wrong label in the cabinet. The cab dimensions should hopefully answer which is the case.
No, it never been modified (except for one thing I did). I bought this from the original owner in 1971, a straight stock Pro Reverb, Fender speakers, tipback legs, black face with Pro Reverb silkscreen on the panel. The label inside is the only thing out of the ordinary, with it identifying the model as Vibrolux Reverb AA864, Production Lot 24.
The one thing? I changed the grille cloth to black. The silver Fenders that followed the black face used a brighter grille cloth, so the blackface looked "old" in comparison.
I know the speakers are 12 inchers, compared to the Vibrolux 10 inches. Put a Radio Shack 12 inch in when I was checking if the speakers were getting old and needed replacement, its a direct fit.