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Peavey Mace VT ?

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  • #1

    Peavey Mace VT ?

    Asking this for a friend. I know this can be done with other amps ,but just wanted to check. Can you pull power tubes in the Mace to reduce power ? If so would the pairs be 1&3 ,2&4, and 5&6 ? Could you pull as many as 4 ?

    Thanks !
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  • #2
    It is a tube power amp, you can do anything to it you could do to any other tube power amp.

    Assuming nothing here, you are aware the tubes are distributed V1-2-5 on the push and V3-4-6 on the pull? And across the line of tubes, the order is V6-4-3-1-2-5? V6 is on the end where the transformer wires plug onto the socket board.

    The tubes are not paired. They are in two groups of three. If you want to remove some and maintain balance, then you remove one from each group. SO starting with XXXXXX, OXXXXO is no more legitimate than OXXOXX or for that matter OXXXOX. The tubes on each side are in parallel, so it doesn't matter which one you yank. Aesthetically, I'd probably pull the end ones.

    You want to pull off four? No reason you can't on the surface.

    But let us look at it practically. Pulling tubes lowers the draw from the power supplies, so the voltages rise. Remove 2/3 of the tubes, and I'd expect a substantial increase in B+. PV tends to bias these cool, so it may not be an issue, but should be addressed.

    Pulling tubes changes the impedance. Tubes are in parallel, so pulling some raises the impedance. The transformer transforms that to the speakers. IN a four tube amp, pulling two doubles the impedance, so you then must plug the speaker into the next lower impedance output. If you have a 16 ohm speaker, it now goes into the 8 ohm jack for the impedance to be right. You have six tubes. Pulling 1/3 of them changes impedance by a less wieldy amount. But dropping the speaker to the next lower impedance output would be wise. Pulling 2/3 of them might put things out of range. Then again it may still sound fine.

    And we have to wonder WHY your friend wants to do this. Power is not loudness. Cutting power in half loses only 3 decibels of loudness. SO this is not the way to make a 160 watt screaming amplifier not loud.
    Education is what you're left with after you have forgotten what you have learned.

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    • #3
      Thank you Enzo ! . No , I did not know some of this. I wasn't aware of the tube arrangement. I was looking at it as if they were paired. I would be most likely to tell him to leave it alone. From what I've read these run hot (temp wise) ,and I wouldn't want him to start other issues.

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      • #4
        Welll yeah they are hot, there are SIX power tubes under there. That will warm up any room.
        Education is what you're left with after you have forgotten what you have learned.

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        • #5
          Some have suggested a cooling fan. I've heard the temp can cause the traces to fail ?

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          • #6
            Traces? No, the copper on the board is my last concern. Heat kills capacitors mainly. Then again, most Mace amps have been motoring along for some 35 years without fans, so I am not so sure they are a necessity now.
            Education is what you're left with after you have forgotten what you have learned.

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            • #7
              And this one seems to be as well. I know he likes the tone so I will advise him to leave well enough alone.

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