1. Welcome to TalkBass 2014! If you're new here, we just went through a major site upgrade. Please post all concerns and bugs to the Forum Usage Issues forum. We will be monitoring that forum. Thank you for all of your feedback.

    The TalkBass iphone/android app is NOT WORKING currently. We're working on it. Tapatalk IS working, so if you need to use an app, use Tapatalk. Try using your browser though - TalkBass is now 100% responsive to your phone/tablet screen size ;)

    Please read the TalkBass 2014 FAQ for lots of great info on the new software.

Blackfacing the Fender PA 100

Discussion in 'Amps [BG]' started by Grissle, Jan 8, 2014.

  1. Grissle

    Grissle Supporting Member

    Joined:
    May 17, 2009
    Likes Received:
    0
    '75 PA 100. Which schematic should I emulate. A Twin Reverb or Dual Showman?
  2. Grissle

    Grissle Supporting Member

    Joined:
    May 17, 2009
    Likes Received:
    0
  3. Steve Dallman

    Steve Dallman Supporting Member

    Joined:
    Mar 5, 2006
    Likes Received:
    0
    Blackfacing in a SF Fender guitar amp is a matter of upping the impedance of the PI (phase inverter), changing the bias balance to a bias adjust, and the removal of rf suppression caps (IF there is no oscillation as a result.)

    I don't see what the advantage in this amp would be. The preamps are nothing like a Fender guitar or bass amp. I don't like changing the bias balance but would prefer to leave the bias balance and add a bias adjust (replacing one resistor with a pot and resistor.) Why not have both? The purpose of blackfacing was to lower headroom, make it easier to break up the amp, and add some high end complexity.

    Tell more about your amp and your goal in the modding?
  4. Grissle

    Grissle Supporting Member

    Joined:
    May 17, 2009
    Likes Received:
    0
    Sorry, I had read in a few places that the PA 100 had almost identical power sections as the Twins and Showman. I also thought that Blackfacing applied to the power section as well, not just the preamp.

Share This Page