Results 1 to 9 of 9

Thread: new bf pr trem problem

  1. #1
    Senior Member scole's Avatar
    Join Date
    May 2006
    Location
    pitman nj
    Posts
    300

    new bf pr trem problem

    i built a aa1164 princeton rev, the trem was working without the switch plugged in. is that normal?

  2. #2
    Supporting Member tubeswell's Avatar
    Join Date
    Feb 2007
    Location
    Wellington NZ
    Posts
    3,891
    Yep - the default mode is 'on'. The footswitch just shorts the LFO circuit to ground when its engaged (That's why you need to have the footswitch to bias the output tubes).
    Building a better world (one tube amp at a time)

  3. #3
    Senior Member scole's Avatar
    Join Date
    May 2006
    Location
    pitman nj
    Posts
    300
    so the trem has to be off to get a good bias reading? i noticed that when i turn the intensity up the bias ma goes up. with the intensity at 0 i get a good reading.

  4. #4
    Supporting Member tubeswell's Avatar
    Join Date
    Feb 2007
    Location
    Wellington NZ
    Posts
    3,891
    yeah - but you get an even more accurate reading with the footswitch switching it off. Sometimes that zero depth setting ain't quite zero.
    Building a better world (one tube amp at a time)

  5. #5
    Senior Member scole's Avatar
    Join Date
    May 2006
    Location
    pitman nj
    Posts
    300
    if i put the switch in, will it hurt the reverb transformer since i dont have the tank hooked up yet?

  6. #6
    Supporting Member tubeswell's Avatar
    Join Date
    Feb 2007
    Location
    Wellington NZ
    Posts
    3,891
    Quote Originally Posted by scole View Post
    if i put the switch in, will it hurt the reverb transformer since i dont have the tank hooked up yet?
    Just don't switch the reverb on
    Building a better world (one tube amp at a time)

  7. #7
    Senior Hollow State Tech Bruce / Mission Amps's Avatar
    Join Date
    May 2006
    Location
    Denver, Colorado
    Posts
    3,040
    The pedal plugged in or not doesn't have anything to do with the OT being run with no load.
    I don't think you'll blow the Reverb driver OT but, it could.
    So, don't run the amp without the tank installed... it is just like running the amp with no speaker load as the 10 ohm tank is the speaker load in this circuit.
    Now you could shove a 2-5watt 10 ohm resistor across the reverb OT's secondary and test away....
    Bruce

    Mission Amps
    Denver, CO. 80022
    www.missionamps.com
    303-955-2412

  8. #8
    Senior Member scole's Avatar
    Join Date
    May 2006
    Location
    pitman nj
    Posts
    300
    how does the rev tank get connected? rev out from the amp to input on the tank or input to input.

  9. #9
    Supporting Member tubeswell's Avatar
    Join Date
    Feb 2007
    Location
    Wellington NZ
    Posts
    3,891
    The connection from the reverb transformer goes to the tank input, and the tank output goes to the grid of the reverb recovery stage.

    I should add that when I said "don't switch the reverb on" without the tank installed in my earlier reply, I was thinking that it would cut the signal going to the reverb circuit, but I see on the PR schematic that both the reverb ft/sw and the reverb level pot are after the tranny and tank, so Bruce is right, you probably shouldn't run the amp without the tank in. You would either need to do what Bruce said, or pull out the 12AT7 to run it without hurting the tranny. (Without the reverb driver tube plugged in, there would be no signal going into the tranny and so it should just sit there with a few hundred volts on the primary winding that wouldn't be doing anything and therefore wouldn't be getting damaged)
    Last edited by tubeswell; 02-03-2009 at 07:46 PM.
    Building a better world (one tube amp at a time)

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Traynor trem problem
    By drewl in forum Maintenance, Troubleshooting & Repair
    Replies: 5
    Last Post: 09-28-2010, 05:44 PM
  2. Testing A Trem Optoisolator
    By Daver in forum Vintage Amps
    Replies: 19
    Last Post: 12-21-2009, 05:19 PM
  3. Ampeg Trem/Vibrato Issue
    By Daver in forum Repair and Restoration
    Replies: 5
    Last Post: 02-20-2008, 11:16 PM
  4. Trem problem
    By drewl in forum Maintenance, Troubleshooting & Repair
    Replies: 5
    Last Post: 06-28-2007, 01:28 PM
  5. Bias-Vary Trem won't wiggle....
    By DMichel123 in forum Debugging Your Build
    Replies: 5
    Last Post: 01-27-2007, 08:19 AM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •