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Looking for schematic for Garnet PM1 mixer

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  • Looking for schematic for Garnet PM1 mixer

    A bit of a long shot but I thought I'd throw it out there.

    I am looking for a schematic for the Garnet PM1 mixer. I had a good look through the Garnet schems at schematicheaven and they aren't close enough to help me out. I am hoping that I don't have to start tracing this out!

    Anyone?
    Big thanks

  • #2
    Too bad.

    What is the problem you are chasing?
    Education is what you're left with after you have forgotten what you have learned.

    Comment


    • #3
      Thanks for asking Enzo, any ideas appreciated.

      I have a Garnet PM-1 mixer that works well with the exception of the
      reverb. I am getting no reverb whatsoever. I checked the Reverb tank
      itself and it works fine with my Princeton.
      I supected the reverb transformer might be the culprit and sought advice on the Garnet amps yahoo group.

      A gent called "Wild Bill" had some good suggestions which I tried:
      There are a number of different parts involved besides the
      reverb tranny. Step one would be to take the cable driving the reverb
      tank input and put it into a small speaker. If you can hear the signal
      fine then the driver circuitry is ok. The reverb driver is essentially
      like a small amp feeding a couple of watts into the tank, at a similar
      load impedance to a speaker.
      If the driver is ok then the problem must be with the recovery part of
      the circuit. A cap or resistor could have opened up, or a tube gone bad.
      Often the connecting cables develop a problem.
      Anyhow, if it drives a speaker then your tranny is fine.
      Wild Bill


      Here's what I replied when I was done testing:
      OK, so I tried your speaker test Wild Bill, and thankfully got signal
      through to the speaker. Thanks!

      So I know that the signal is getting through from the tranny and
      that the reverb pan is good as well. I followed the signal path from
      the reverb pan output and it heads straight to the master reverb pot.
      I checked this cable for continuity and made sure it wasn't grounding
      out either. This cable checks out. From the master verb pot the
      signal goes through a resistor (did an in-circuit test on this
      resistor and it seems resonable) and then to the individual channels
      "reverb on" switch.

      From there it heads to the first 12AX7 pin 7. After that I am not
      sure. It's a bit of a rats nest around the three 12AX's! I had a good
      look around at all the components and nothing looked like it has
      taken heat or buldgy caps etc.

      So now I am stumped, I spent some time swapping in and out different
      12AX's and there is no change in the reverb situation.
      I keep thinking that there is something simple I am missing. (Like
      usual...)

      Any advice?
      Many thanks,
      Brian

      The Garnet PM-1 is a basic (not to me at the moment!) 6 channel into mono line out mixer. There are 2-12AX7 and 1-12AU7. No power or rectifier tubes.

      Comment


      • #4
        The test for a recovey stage is to turn the reverb up midway, then touch the tip of the return cable plug. it should make hum. Seems odd to hit the pot first, but so be it. Touch the grid of that tube with your meter probe or a small screwdriver, THAT should hum. Voltages on that tube look right? B+ and a small cathode voltage? Even though the pan is good, was it conected right? Cables not swapped. The wire that drove the small speaker should be in the INPUT jack.
        Education is what you're left with after you have forgotten what you have learned.

        Comment

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