Wanted: Vibrolux Reverb AA864 schematic

[Keystring]

I don't think that my amp is wired according to the AA270 schematic since the convenience outlet on the back of my amp doesn't have a ground, it's a two prong receptacle. On the AA270 schematic, there's a three prong outlet.

I'm going to have to open up the chassis soon, then I'll post again with a follow-up. Thanks!

Which means it's probably the AA763 which does have the two prong plug..

Which would match up with the GZ34 that is on your tube chart...

BTW.. The amp model should be on the tube chart ..


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[Bruce / Mission Amps]

Hey.. look and see if your aux 120v outlet socket is wired backwards with the black hot lead on the neutral lug and the white neutral on the hot lead of the power cord.
Wide lug is thealways the neutral and narrow his 120v.

[Albert Kreuzer]

Update to the AA864/AA964 thing:

The tube chart says AA864 (production run #5)
S/N is A 02661
Speakers are Jensen

The circuit is exactly like the AA964 schemo that's on the web, the only exception being the resistor from the bias pot to ground (15k instead of 27k). This is an export model, so maybe the bias tap off the PT was slightly different on these?

Cheers,
Albert
www.albertkreuzer.com

[studioit]

Bias circuit question

Albert, I just happen to be working on the same amp and also couldn't find a schematic. The one I have is an AA864 Aug 66 (PH) production 68 ser# 06961 with original Jensens as well.
It does seem to be the same as the 964 schematic for the most part. This one had a 15K resistor on the bias pot but it wasn't original so I was wondering about that. What value is the dropping resistor feeding the bias circuit on the one you have? This one is 2700 ohms which I've never seen before and can't find a schematic of any fender blackface that uses that value. This is definately an original part though as it's the right looking carbon comp and it looks like factory solder job.
thanks
Ian

[Albert Kreuzer]

Hi Ian,

470 Ohms in this amp, like in the schematic. Never saw a 2k7 bias resistor in a Vibrolux or Deluxe Reverb, but had one in a '66 Bassman AB165 with SS rectifiers (obviously original, see picture). The AB165 schematic shows a 470 Ohms resistor.

Hope this helps

Cheers,
Albert
www.albertkreuzer.com

[studioit]

Thanks Albert,
I was just curious.
Ian

[melodymaker]

Im a total rookie trying to get more familiar with my amp... Ive also got an AA864 vibrolux..I think it s a 68 or 69... Im wondering what the pot accessible form the bottom of the chassis adjusts.. iT's located a few inches behind the power tube closest to the preamp tubes.... is this for biasing??? thanks... any newby info could help.