Bias mod & recap complete!

Discussion in 'Amps & Cabs' started by paradox, Apr 29, 2005.

  1. paradox

    paradox Active Member

    Joined:
    Dec 12, 2004
    Messages:
    1,183
    Likes Received:
    14
    Location:
    Jacksonville, FL
    Here's some pics of the princeton reverb I picked up that needed a little help:

    The original recap job was, well, less than perfect. axial caps were used inside the chassis instead of the "can cap", also caps of a unknown manufacturer were used for the bypass caps. I yanked all the caps in question and put in a new can cap and bypass caps. Note in the first pic, the original recap missed a cap! There is an original bypass one for the trem circuit back by the rear panel. BTW, a company in Arizona bought the tooling line that the defunct Areo M company had, and the can I bought to use here is actually one of the new ones.

    Before:

    [​IMG]

    After:

    [​IMG]

    [​IMG]

    In the second picture you can also see the bias pot addition thanks to cb. In place of the original 22K resistor are now a 18k resistor and a 10k pot. The original wire for the bias voltage was moved to the wiper of the new pot. I measured the idle current before any changes were made to the amp, one tube was at 18ma and the other was at 22ma. Since I've just but back in the original tubes for now I adjusted the idle currents to these values. Thanks again cb for the help on the bias circuit!!!!

    Heres a few more pics:

    [​IMG]

    [​IMG]

    [​IMG]

    The amp is really pretty clean overall, except for some of the tolex tears on the front. In fact one bottom corner is missing a big piece of tolex. I guess this gives it a little character, this happens with age. I never noticed in the ebay pictures but it was there. I really had been wanting a lower wattage 6v6 amp and with cb's help was going to build one from a champ, however I saw this one pop up on ebay and I couldn't hold back. These little princetons sound really great. I had been missing the good old fender reverb and tremolo too, its good to have it back after all these years.
     

Share This Page