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Standel tremolo circuit - Can anyone ID this transistor?

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  • Standel tremolo circuit - Can anyone ID this transistor?

    I have a 1969 Standel Studio amp with the dreaded epoxy potted circuits, and the tremolo has failed. I'm considering attempting to build a replacement circuit using the schematic available on the Standel website, but having difficulty identifying one of the transistors in the circuit. The schematic can be found here:

    http://standelamps.com/support/schem.../redmodule.pdf

    The transistor in question is the one on the left, which appears to be labeled "S 2047". I have searched high and low for a datasheet for that number, or even just some reference, and come up with nothing. Does anyone have any idea what it could be, or what would be a good substitute for it in that circuit?

  • #2
    You won't find a data sheet on it because it is a house number. I tend to think it is not particularly critical, but as long as they are there, why not ASK Standel if they would suggest a cross? And for that matter, a voltage apapropriate PNP transistor from your parts bin might make it work. If it only works half ass, at least you know the thing is trying.
    Education is what you're left with after you have forgotten what you have learned.

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    • #3
      I tried it with a 2N3096, worked fine. Just about any small signal PNP with HFE>200 and Vceo > 40 will do (caveat: the schematic isn't too clear).

      Nic
      Experience is something you get, just after you really needed it.

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      • #4
        Originally posted by Enzo View Post
        You won't find a data sheet on it because it is a house number. I tend to think it is not particularly critical, but as long as they are there, why not ASK Standel if they would suggest a cross? And for that matter, a voltage apapropriate PNP transistor from your parts bin might make it work. If it only works half ass, at least you know the thing is trying.
        Thanks Enzo. I actually did send an email to Standel, and didn't get any response.

        Originally posted by nickb View Post
        I tried it with a 2N3096, worked fine. Just about any small signal PNP with HFE>200 and Vceo > 40 will do (caveat: the schematic isn't too clear).
        Nic
        And thanks Nic... I appreciate the info. One question: Did you end up using the Clairex LDR or substitute something else?

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        • #5
          dissonance - I just built the oscillator section to experiment.
          Experience is something you get, just after you really needed it.

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