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Bassman aa864 clone noise

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  • Bassman aa864 clone noise

    Hello,

    I've just finished to build my first amp. Is a Bassman aa864. It works and sound, but they have some pops, and crack noise. If I pull of V2 the noise dissapear, if I desolder wire pin 8 ( cathode ) from V2 the noise disappear...

    Anybody can help me?

    Thanks.

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  • #2
    Welcome to the place and nice looking build!

    Pulling V2 is nearly the same as disconnecting it's cathode. Either way, you stop the tube from conducting, so I'm not surprised results are the same. What about V1? If you pull that does the noise stop? By pulling V2, you've eliminated everything passed that, but it could still be anything before that. First thing I'd do is try tube substitution with known good tubes. You could simply have a bad tube. Double check your solder connections on the sockets.
    "I took a photo of my ohm meter... It didn't help." Enzo 8/20/22

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    • #3
      I don't like to see those small plate resistors. Are they new carbon comps? 1/4w is only rated 250v on the new ones.

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      • #4
        Hi,

        yes, they are new carbon comp resistors. Do you think it's a problem of plate resistors? Her we go my voltaje chart.

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        Last edited by Davebassman; 11-17-2017, 07:17 AM.

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        • #5
          cathode voltage is high for me,in general its around 1,5V.same as the anodes at 290.
          When there is hum i always go to grounds first,other things are filament heater balance and proper phase in the output tubes.
          Did you also connect the ground switch?
          Last edited by alexradium; 11-17-2017, 01:35 PM.

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          • #6
            No, the ground switch is for stetic only. What is the reason that the cathode voltaje is high??

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