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new bf pr trem problem

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  • new bf pr trem problem

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

  • #2
    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)

    "I have never had to invoke a formula to fight oscillation in a guitar amp."- Enzo

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    • #3
      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.

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      • #4
        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)

        "I have never had to invoke a formula to fight oscillation in a guitar amp."- Enzo

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        • #5
          if i put the switch in, will it hurt the reverb transformer since i dont have the tank hooked up yet?

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          • #6
            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)

            "I have never had to invoke a formula to fight oscillation in a guitar amp."- Enzo

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            • #7
              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

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              • #8
                how does the rev tank get connected? rev out from the amp to input on the tank or input to input.

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                • #9
                  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, 06:46 PM.
                  Building a better world (one tube amp at a time)

                  "I have never had to invoke a formula to fight oscillation in a guitar amp."- Enzo

                  Comment

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