70,s twin

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by Del, May 6, 2003.


  1. Del

    Del Member

    Messages:
    317
    Joined:
    Jan 4, 2002
    Location:
    London
    Can a 70's silverface twin be converted to a black face,any links to companys that provide parts:D
     
  2. Josh

    Josh Guest

    Del,
    Generally speaking, the earlier the silverface model is, the easier it will be to blackface. The most difficult ones to BF are the late 70's 135w ultra-linear models.
    Most of the differences are in the phase inverter, if I recall correctly(been a long time since I have done it). Most of the parts can be found at basic electronic suppliers like Mouser electronics.
    You will have to find a schematic for your model, and one for a mid-60s twin, ...just compare the differences.
    Josh
     
  3. Jon Silberman

    Jon Silberman 10Q Jerry & Dickey Gold Supporting Member

    Messages:
    35,577
    Joined:
    Jan 3, 2002
    Location:
    Northern VA
    It's my understanding the ultra-linear models cannot be converted to blackface specs.
     
  4. Josh

    Josh Guest

    You can disconnect the ultra-linear taps or replace the OT.
    I think the PT ran at higher than vintage voltage though.
    Josh
     
  5. Jon Silberman

    Jon Silberman 10Q Jerry & Dickey Gold Supporting Member

    Messages:
    35,577
    Joined:
    Jan 3, 2002
    Location:
    Northern VA
    Theoretically and with enough effort, I suppose anything is possible.

    Do yourself a favor. If you want a cheap SF TR to convert to BF specs, make it a '68-'76 100 watt model.

    Stay far away from the '77-'82 135 watt ultra-linear model.

    I'm no tech myself, but I read alot. Never have I ever heard of anyone who bought one of those with the goal of BF'ing it succeeding to his satisfaction.
     
  6. Del

    Del Member

    Messages:
    317
    Joined:
    Jan 4, 2002
    Location:
    London
    It is an early 70's point to point all oragional and CHEAP:D
     
  7. Josh

    Josh Guest

    I would go for it...easily blackfaced, altough the early 70s twin sounds good regardless. Get a cap job, and maybe a set of tubes with a proper bias. You could sell it and get your money back at any time, these amps will only go up in value

    Josh
     
  8. Jon Silberman

    Jon Silberman 10Q Jerry & Dickey Gold Supporting Member

    Messages:
    35,577
    Joined:
    Jan 3, 2002
    Location:
    Northern VA
    Follow Josh's advice IMMEDIATELY! :D
     

Share This Page