Ampeg VT-22

Discussion in 'The Squawk Box' started by Batman, Mar 7, 2012.

  1. Batman

    Batman Senior Member

    Messages:
    6,709
    Likes Received:
    6,986
    Joined:
    Nov 10, 2011
    Does anyone have any experience with the Ampeg VT-22 Combo?

    I just picked up one (with assistance. . .it's a heavy b*$tard!) that needs some work; non-working reverb, no speakers and a loud hum when plugged into an external cab. It was only $140 so worst case I can gut it and use the working parts to start a 18-watt TMB project that I've been considering.
     
  2. dlmorley

    dlmorley Senior Member

    Messages:
    1,509
    Likes Received:
    624
    Joined:
    Feb 14, 2008
    I had a VT40 (same amp but 4 x 10)
    Great amp. MASSIVELY loud! The reverb is wonderful.
     
  3. hipofutura

    hipofutura Senior Member

    Messages:
    6,987
    Likes Received:
    2,418
    Joined:
    Feb 8, 2009
    That's a very cool amp. I'd build a Fender BF style head cab and dump the combo. The slant face on the chassis screams for it. Then tweek it for more O/D. I wouldn't gut it as there's too much good stuff there.
     
  4. Batman

    Batman Senior Member

    Messages:
    6,709
    Likes Received:
    6,986
    Joined:
    Nov 10, 2011
    Don - That's probably what I'll end up doing. I'd like to end up with an amp that gives me nice distortion without deafening me. The only thing that worries me with my relative lack of experience is diagnosing and fixing the hum issue; I can mod and tweak quite well but I'm no amp technician.
     
  5. hipofutura

    hipofutura Senior Member

    Messages:
    6,987
    Likes Received:
    2,418
    Joined:
    Feb 8, 2009
    Tracking down hum can be a problem, but not always. The hum is the result of aging, so that eliminates a design/layout problem. The obvious sources are tubes and filter caps.

    This amp, like some old Fenders, has a hum balance pot. It could be as simple as adjusting it. They did this because the PT didn't have a 6.3V CT. I'd strip the HB circuit and run a 100 ohm resistor to ground for both sides of the heater tap.
     
  6. Cygnus X1

    Cygnus X1 Senior Member

    Messages:
    6,570
    Likes Received:
    2,963
    Joined:
    Jul 18, 2009
    Backing up Hip, probably due for filter caps and filament CT lift.
    Death cap/modernizing the power section might be in order.

    I can work on these but have no experience modding for more gain.
    They take pedals so well I'd be wary of doing much in that area anyway.
     
  7. Xavier_32

    Xavier_32 Senior Member

    Messages:
    1,479
    Likes Received:
    321
    Joined:
    Nov 23, 2009
    The guitarist in one of my bands plays through a VT-22. I've used it a bunch, too. I find that while the amp gets great natural distortion without going too loud, the problem is that it doesn't get loud enough for a medium sized venue without being mic'd. You keep turning the volume up, but instead of getting louder, the the volume stays the same and the distortion just gets gnarlier.

    All that put aside, it DOES get some awesome distortion and take pedals quite well if you need more.
     
  8. EvLectric

    EvLectric Senior Member

    Messages:
    4,618
    Likes Received:
    2,014
    Joined:
    Feb 17, 2010
    Up until a few months ago I had a factory master volume for one, but lost it when I let a storage shed go. It was in a little reverb on/off looking box & plugged into the back of the amp. I would think you could probably find a schematic for it online somewhere & one of these guys could build it for you.
    As far as it not being loud enough, that's a first for me. That thing was one of the loudest amps I ever heard in my life. It's probably the speakers maxing out rather than the amp. New high wattage speakers or a 4-12 cab should take care of that.
     
  9. Xavier_32

    Xavier_32 Senior Member

    Messages:
    1,479
    Likes Received:
    321
    Joined:
    Nov 23, 2009
    That's definitely a possibility. It still has the original speakers that came with the amp from back in the '70s, and as far as I know, it's never had any work done other than a tube replacement (with the default NOS tubes.)
     
  10. dlmorley

    dlmorley Senior Member

    Messages:
    1,509
    Likes Received:
    624
    Joined:
    Feb 14, 2008
    A VT22 not being loud enough is new to me too! Massive volume. I'd say it needs a service!
     
    1 person likes this.
  11. Batman

    Batman Senior Member

    Messages:
    6,709
    Likes Received:
    6,986
    Joined:
    Nov 10, 2011
    Filter cap replacement is pretty straight forward. For the heater filaments I want to make sure I am on the same page as you.

    On this amp there is no 6.3V CT, therefore to lift the CT I have to create a voltage divider like this where Vout = Vin*R2/(R1+R2). From the reading I have done, I have read both the first and last filter cap are good places to tap into B+. The argument for first is that this yields the least hum from the heaters feeding back into the B+. Where do you suggest is the best place to tap into B+?

    Again, from my reading, the Vout spread seems to be somewhere between 20 and 50 volts DC from the B+ (plate voltage). What Vout value should I be looking for?

    If I use the first filter cap (337V from the schematic) then it looks like the following values would work;

    R1=100K
    R2=10K

    Vout=30V
     
  12. hipofutura

    hipofutura Senior Member

    Messages:
    6,987
    Likes Received:
    2,418
    Joined:
    Feb 8, 2009
    I wouldn't bother with the voltage divider. I've had great results with just running a 100 ohm resistor to ground from the two heater winding taps. I do it at the pilot light.
     
    2 people like this.
  13. Batman

    Batman Senior Member

    Messages:
    6,709
    Likes Received:
    6,986
    Joined:
    Nov 10, 2011
    Sounds good; Thanks Don!

    I hope to tear into this later today. I will post pics of what I find and start a parts list. Do you have a preference on filter caps or is this somewhat irrelevant to the overall tone?

    Barry
     
  14. psc3

    psc3 Member

    Messages:
    79
    Likes Received:
    73
    Joined:
    Jul 29, 2010
    A VT22 is a V4 (in combo form). This should be loud as thunder! There is a hum balance knob on the back. Get some work done on her and she will blow down walls.
     
    1 person likes this.
  15. Batman

    Batman Senior Member

    Messages:
    6,709
    Likes Received:
    6,986
    Joined:
    Nov 10, 2011
    WOW! Once I got inside, this thing is a bit of a Rat's nest! Someone has been in here before. . .

    It looks good from the front. . .

    [​IMG]

    and the back. ..

    [​IMG]

    Doesn't look too bad from the top. . .

    [​IMG]

    But not so good under the reverb tank. . .

    [​IMG]

    Although the mods and trace repairs are pretty obvious from the photo, the pre-amp tube sockets are all loose on their CB's and most of the pins of the power tubes are loose. I think this is going to require a fair bit of surgery to get it back to playable condition. I'm not sure I want to spend that much time and effort on an amp that is well louder than I'll ever need.

    I'm looking for opinions; should I fix this up and sell it or use it as a donor platform for another build?
     
  16. LesPaulCat33511

    LesPaulCat33511 Junior Member

    Messages:
    5
    Likes Received:
    0
    Joined:
    Sep 25, 2012
    needs caps for sure
    Plenty of cold solder joints there I'll bet
    Might be the impedance due to one speaker is off, therefore your bias is off
    Careful with that hum balance - do you know how to bias?
    Mine is 42 years old and louder than anything anyone's got
    Best tone EVER
    Anyone hear back from him lately
    Hope he didnt fry himself
    Very dangerous amp to work on
    Tome to die for
     
  17. Batman

    Batman Senior Member

    Messages:
    6,709
    Likes Received:
    6,986
    Joined:
    Nov 10, 2011
    Hey Dude - Welcome to MLP!

    I haven't had time this summer to do anything with this amp so it's parked in a corner waiting for me to have some spare time.
     
  18. LesPaulCat33511

    LesPaulCat33511 Junior Member

    Messages:
    5
    Likes Received:
    0
    Joined:
    Sep 25, 2012
    Thanks Batman
    I joined just to reply to you and your amp !
    Mine is a 1970
    Had the speakers replaced
    Retubed a bunch of times
    Nothing sounds like this
    Super Loud and Clean

    I wouldn't mod it if I were you until you got it to work right as it was designed to, and hear what it can do

    I think John at the Tubesstore can help you find tubes and stuff
    Also Bob at Eurotubes helped me revive this thing when the majority wanted me to mod it

    Real parts are available
    You will be amazed
     
  19. HRC

    HRC Senior Member

    Messages:
    7,225
    Likes Received:
    6,164
    Joined:
    Feb 17, 2010
    I've had 3 VT-22's and they are louder than any other combo I've ever had. Something isn't right if a VT-22 isn't loud enough IMHO.
     
    1 person likes this.
  20. TeaForTwo

    TeaForTwo The Guitar Whisperer Premium Member

    Messages:
    7,072
    Likes Received:
    14,585
    Joined:
    Dec 2, 2010
    I also owned three VT-22s...Very loud amps, with great tone....

    They're tanks, and heavy...
     

Share This Page