NAD: Ampeg VT-22

Discussion in 'Amps [BG]' started by christw, Jan 22, 2013.


  1. christw

    christw Get low!

    Joined:
    May 11, 2008
    Location:
    Dayton OH
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    Endorsing: J Worrell Bass
    After a brief search to quell my GAS, I found myself a VT-22 in decent shape. It's dead silent and looks like it's been a used a bit. The speakers were replaced with Sunn transducers ('77 Eminence like these) by a prior owner according to the guy I bought it from. I don't care either way, I bought it for the amplifier section at a fair price. Power tubes are 3x Magnavox + 1x Sovtek 7027A. It'll see a tech sometime soon just in case.

    Now I'm off to play with it for a little while...

    [​IMG]
    [​IMG]
  2. christw

    christw Get low!

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    Well, this thing sounds great but I don't have any speaker cabinets at home I can really push it through. It's farting the Kustom 215 by the time it hits light OD so cranking it will have to wait. I'm digging on the EQ and voicing so far. Like most Ampegs, it plays very nice with my P's. It might help fight off my J Bass lust.

    As far as tubes, the Sovtek is looking a little blue but the stock Magnavox still look free and clear. I'm still thinking I'll at least try 6550's in the amp but I'd have to drill out the bear trap retainers to make room. That will probably be my biggest stalling point. I don't like doing permanent modifications to vintage amps but it's already got non original speakers so what the heck, right? ;)
  3. AllenLee

    AllenLee

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    Jan 6, 2013
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    Texas, USA
    That looks like a sweet resto/mod project!
  4. JimmyM

    JimmyM Supporting Member

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    Apopka, FL
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    Endorsing: Ampeg Amps, EMG Pickups
    You're way more ambitious than me. I'd rather just use 7027's and call it a day.
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  6. christw

    christw Get low!

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    The unhealthy looking Sovtek 7027A in there is my excuse. Well, that and the matched quad of lightly used Aggie 6550's just hanging out. I'm probably going to do the work on this one myself. A labeled printed circuit board is a lot less scary than a point to point amp and a schematic. :p
  7. B-string

    B-string Supporting Member

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    Nov 21, 2008
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    A blue glow inside a tube means very little unless only one has it. Blue glow is normal in operation.
  8. christw

    christw Get low!

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    Only the Sovtek is glowing blue at the moment.
  9. B-string

    B-string Supporting Member

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    That may mean the Sovtek does not have a beam former as precise as the original tubes (more visible electron cloud). Does not mean it is bad, if no cloud can be seen in the original tubes even with a signal applied it could signal troubles with those or supporting components. Note : could...meaning possible not definite.
  10. christw

    christw Get low!

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    Let me revise my statement, the Sovtek is noticeably more blue during operation. I need to be careful with my word choice!

    I just pulled out the VT-22 and did a little research online. As it turns out, I believe the squareback Eminence speakers are stock. I've found several other late '70's VT-22 with the same speakers. The speakers are from the 17th week of '77. The last revision listed on the schematic was 8-9-77. I'll check some codes later but it's looking like it's a '77. Oh yeah, it has the master volume too.

    Naked amps! Mesa Buster / VT-22. Look at those trannies! :p

    [​IMG]
  11. B-string

    B-string Supporting Member

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    So long as you are in the mindset of modding ;) I moved the OT forward on my old V4B to provide more clearance between the OT and output tubes. Made a big difference in OT temp and cooling to the two output tubes. :)
  12. SactoBass

    SactoBass There are some who call me.......Sactobass Supporting Member

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    Is the V-22 (amp portion) the same as a V4/V4B?
  13. B-string

    B-string Supporting Member

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    Yes, same circuit.
  14. beans-on-toast

    beans-on-toast

    Joined:
    Aug 7, 2008
    Here are the specs of the V4. Take note of the tone control range. Nice to know what they are.



    [​IMG]

  15. beans-on-toast

    beans-on-toast

    Joined:
    Aug 7, 2008
    Note that the ultra-hi switch function is dependent on the volume setting.

    Here is an explanation as to how it works.
  16. christw

    christw Get low!

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    I like that idea. It already looks cramped with 7027A in there. We'll see how far I get in these next few weeks. I'll be ordering a few bits to make the 6550 conversion and going from there. I might build a headcase in the meantime...

    Thanks! My particular amp's mids are labeled 300 / 1k / 3k. Nice to know how that ultra high works.
  17. B-string

    B-string Supporting Member

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  18. beans-on-toast

    beans-on-toast

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    Engineers love changin things!
  19. christw

    christw Get low!

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  20. B-string

    B-string Supporting Member

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    Here ya go http://www.tubesandmore.com/products/S-H143
    I cut the old bear trap clamps off flush, drilled new holes and used machine screws through the component side with kept nuts (leave some length exposed), another nut and lock washer to attach the spring lugs.
    Fan I added wad an old 117VAC fan I had laying around (was a little loud).
  21. christw

    christw Get low!

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    Well, I went to Lowe's to get some plywood cut. The top/bottom and left/right side were both 1/4" different and they said they couldn't fix it. (Recutting them would have been too much?) I left them there. :rollno:

    I've exhausted the list of local cabinet makers. They don't do small jobs. I can't do any work here thanks to my mother's hoarding so I'm at a very frustrated impasse. Looks like I'll farm another head case out to John...

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