Vibrolux Reverb AA864 schematic

[73GTV]

https://i.imgur.com/nc8kE0c.jpg
https://i.imgur.com/lEq5sTe.jpg

My 1965

[oj]

Vibrolux AA864 circuit. It is not just an AA964 with Jensens or Oxford or Utah Coil or whatever "different" speakers. I just had a 1965 in and it has a higher voltage preamp rail. Fender was NOT overly diligent about gluing in the proper tube charts either so you may or may not have an AA964 with an AA864 circuit or vise versa, an AA864 with an AA964 chart glued into the cabinet. It simply runs the phase inverter 12AT7 and the 7025s and everything else kind of up around Twin Reverb preamp voltages or for that matter look at the Bassman AA864 preamp voltages, and drop a few volts off for the 5AR4 rectifier tube, because the AA864 Vibrolux Reverb chart shows a 5AR4, two 6L6GCs, and the usual two 12AT7s PI and reverb driver and the three 7025s which were usurped some time ago by the 12AX7A tube. For Gits & Shins: The 7025 was supposedly designed to hold the hum down to an average of 1.8 microVolts with a maximum allowable hum of 7 microVolts. The 12AX7A was also designed to have the same 1.8 microVolts of hum, however they were NOT tested to cull out anything that was over 7 microVolts of hum, so there can be more noisy 12AX7As than 7025s. Since no one makes a real 7025 anymore that is kind of a moot point now. To make a 7025 just test the tubes and reject anything with more than 7 uV of 60Hz hum in the 10KHz bandwidth of amplification. I digress, sorry.

SO true, so true ! I have me self a SR from 68 that have tube chart saying AB 763 but should be saying AB 568. And over here in Sweden I have seen this often especial with amps after 65.

[ogeecheeman]

I'm a tech / player. owned a 65 vibrolux.date code OJ. exactly like yours. let it get away from me-money problems.when i got it years ago the power tranny had been smoked. the owner put in a super reverb tranny.he never could make it work.i had to rebuild the voltage divider to accommodate the higher plate voltage.when i was done i had a 45 watt vibrolux w/jbl k110's. i do recall having to use a solid state rect.it was a tone monster. don't know if that's it but it would have come from a music store in savannah,ga about 15 years ago. if it is i have lots of vintage tube amps and would love to have that one again for a swap.I had orange drops in the driver circuit. all other trannies were original. i have the thunderfunk fender transformer book.if you send me the number on the PT I can let you know if it is a SR tranny