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Vibrolux Reverb AA964 vs. Deluxe Reverb AB763: what are the differences?

Discussion in 'Glowing Bottle Tube Amp Forum' started by theprofessor, Nov 30, 2020.

  1. theprofessor

    theprofessor Poster Extraordinaire

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    It looks likely that I will start a Vibrolux Reverb build sometime in the near future.

    I have been going through the layout and schematic, making up a parts list. I thought it would be interesting to compare it to the famous AB763 family -- especially the '63 Deluxe Reverb. While I imagined that the main differences between, say, a blackface DR (AB763) and a blackface VR (AA964) would be the use of 2x10" speakers and a pair of 6L6's instead of a pair of 6V6's, what I did not recognize is that those look to be the only differences -- aside from the different transformers to match the power tubes. Upon a fairly quick run through the layout of the AB763 versus the AA964, I can find no differences. Not even one cap or resistor. And despite the different power transformers (DR 125P23B vs. VR 125P26A) and output transformers (DR 125A1A vs. VR 125A6A), the voltages are nearly identical (and the filtering is exactly the same, too: 4x16uF caps).

    So, three questions arise:
    (1) What, if anything, am I missing?
    (2) Why isn't a Vibrolux Reverb a part of the AB763 family, just like the non-reverb Vibrolux is?
    (3) Won't a Vibrolux Reverb built according to the '64 schematic "just" sound like a '63 Deluxe Reverb at relatively the same voltages, but using 2x10's and 6L6's, with transformers that can actually supply the current without stress? So: a Deluxe Reverb but with more clean power and headroom, and with 2x10 speakers.

    I suppose I thought there would be at least a little bit of difference in the tone stack or something...

    I've included @robrob 's signal flow layout of the AB763 Deluxe Reverb and a layout of the AA964 for purposes of comparison.

    AB763_Deluxe_Reverb_Layout_Signal_Flow.gif Vibrolux-Reverb-AA964-layout.jpg
     
    Last edited: Nov 30, 2020
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  2. schmee

    schmee Doctor of Teleocity

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    Yep, very much the same amp and even the same size! Just a 6L6 2x10 DR.
    Same small filters
    same small choke

    Why 1964? I dont know, but they made the non reverb BF Vibrolux a AB763, They maybe didn't fully decide on the reverb version until '64 I guess. Maybe they were debating on if they even needed a 2 x 10 in their lineup?

    BTW, I converted my 65 BFDR to 6L6's for a while. It was a much brighter amp... too bright for me really. Just the 6L6's I guess.
     
    Last edited: Nov 30, 2020
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  3. Wally

    Wally Telefied Ad Free Member

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    The .Vibrolux Reverb is a 1964 circuit. The First BF Vibrolux was the AA763 Vibrolux 1x12 without reverb. Imho, they should have built the Vibrolux Reverb in that 1x12 format...just as they should have built the Pro .reverb in the 1x15 format instead of calling it the VibroVerb. The 2x10 should have been a Super Reverb...just as all .Supers had been. The 4x10 guitar amp should have been continued as the Concert/Concert reverb.I don’t know why they did not stick to their establish tube/model relationships. fwiw, all BF/SF guitar amp circuits are very similar if not identical in the preamps. The Super Reverb used a .033mfd midrange cap versus the .047mfd in the others, iirc.
     
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  4. Mark the Moose

    Mark the Moose Tele-Afflicted

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    The only other thing I could find was the 2-amp fuse instead of the 1-amp fuse...which goes with the bigger iron and tubes.
     
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  5. King Fan

    King Fan Poster Extraordinaire Ad Free Member

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    Very cool, Professor. And I'm jealous. I've always wanted to play a VR; they seem to get at least as much love as any BF amp, if not more.

    The 1964 thing makes sense; so in effect it is part of the family. For those who don't know it, I imagine Rob's comparison table and his whole AB763 comparison page would be handy. I suppose we could mentally add the VR and the '68 Custom VR'; and you've done the VR homework for us "on the board," as it were. :)

    upload_2020-11-30_12-8-2.jpeg
     
    Last edited: Nov 30, 2020
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  6. slider313

    slider313 Tele-Afflicted Silver Supporter

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    The Vibrolux Reverb followed the AA/AB 763 1x12 Vibrolux Amp. The new design was drawn up in September, 1964; hence the AA964 designation and had 2x10" speakers with on board reverb. It was put into production in October of 1964.
     
  7. Ten Over

    Ten Over Tele-Holic

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    The faceplates have different names on them. The rear plates also have slight differences. The Vibrolux frequently has the wrong circuit number on the tube chart and the Deluxe doesn't.. The Vibrolux has a 27K resistor in the bias circuit and the Deluxe has a 10K. The Vibrolux has a 100 ohm tail resistor in the NFB circuit and the Deluxe has a 47 ohm.
     
    Last edited: Nov 30, 2020
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  8. JRapp

    JRapp Tele-Holic

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    I just converted a 1968 VR to a 1x12" format with Bassman multitap iron and I like it much better. 3x10 or 4x10 is great, but the 2x10 array just doesn't cut it for me.
     
  9. schmee

    schmee Doctor of Teleocity

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    I have had trouble with 2 x 10 also. in 4 x 10, the use of those lightweight cheap speakers seems to work out, be it Tweed Bassman or Super rev. In 2 x 10 they need to be more robust IMHO. Although there have been some 2 x 10 I liked. It just seems like a finer line to walk.
    I've never had the BF 1 x12 Vlux but have had 2 of the Brown ones and they are superb small amps that will do most any gig.
     
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  10. theprofessor

    theprofessor Poster Extraordinaire

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    Ah, yes. Two resistors are indeed different. Thanks!
     
  11. John Owen

    John Owen Tele-Afflicted Ad Free Member

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    I have wondered several times why my 1965 VR tube chart said AA763. It never occurred to me that it was just the wrong circuit number! Doh!
     
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  12. Wally

    Wally Telefied Ad Free Member

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    That small difference in that tail resistor has to do with the output impedance of the OT, correct? In the 8 ohm amps, there is that 47ohm. With the 2ohm and 4 ohm OTs, they used the 100ohm.
     
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  13. slider313

    slider313 Tele-Afflicted Silver Supporter

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    I've tried my Vibrolux Reverb into both 4 ohm 12" and 15" speakers and prefer it with the 2x10 format.

    I agree that smaller magnet 10" speakers don't work well in this amp. I wouldn't run a pair of Jensen P10R/C10R's or anything with the same specs. While they work well in a 4x10 format, they just don't hold together well with this circuit. Both the Oxford 10L5 and Jensen C10NS, were stock offerings in the blackface era and work well.
     
  14. Wally

    Wally Telefied Ad Free Member

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    Tube charts often are irrelevant and grossly incorrect. I have owned a mint 1967 5e3 Deluxe that had a 5F6A Bassman tube chart in it. I have owned a SF Dual Showman Reverb that had a chart for an AB165 Bassman.
     
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  15. John Owen

    John Owen Tele-Afflicted Ad Free Member

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    Next you're gonna tell me I can't believe everything I read on the inter-webs???!!:eek:
     
  16. King Fan

    King Fan Poster Extraordinaire Ad Free Member

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    Wow, @theprofessor , you start the most interesting threads.

    I assume it’d be possible to build a 6V6 VR. Or would that be a 2x10 DR? :)
     
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  17. trancedental

    trancedental Tele-Meister

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    The 6G16 Vibroverb is also very similar to the AA763 Deluxe Reverb, same tube line up / functions / controls but running 6L6's / 5881's. Also has no bright switches & even has the 47pF "Bright" cap on the reverb channel.
     
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  18. Wally

    Wally Telefied Ad Free Member

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    The 6G16 has a bias vary tremolo circuit...big difference compared to the opto-isolator in the DR and larger
    Fender BF/SF guitar amps. The tapped treble pot is a biggie, too. My prototype Pro has those tapped treble pots and it does something different from any BF amp.
     
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  19. Ringo

    Ringo Poster Extraordinaire

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    At one time I owned a drip edge circa 1968 Deluxe Reverb and same year Vibrolux Reverb. I sometimes would gig with both of them, what a great sound.
    They are almost exactly the same size, IIRC the VR is 1 inch wider to accommodate the 2-10" speakers.
    Both are similar, the 6L6s and 10s in the VR plus more power made it different.
    I'd love to have one of each again , back then I decided that I liked the DR better so I sold the VR.

    Looking forward to seeing the progress of your build theProfessor, I wish I the the time patience and know how do to build an amp.
    I've refurbished a bunch of them but I had someone else do the electronic work.
     
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  20. David Barnett

    David Barnett Doctor of Teleocity

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    Seems like the $130 difference between a Deluxe-Amp and a Vibrolux-Amp, in 1964 dollars. must've been mostly profit.
     
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