bias problems

  1. SoreFingers613

    Just bought a 2007 JCM 2000, gain loss, hardly any bottom end

    Purchased over the internet, no return policy, the seller claimed lots of life left in the tubes. This is my 2nd JCM 2000, (should have kept the first one), I played the first one and this one through a 1960a cab. This head is missing the nice full bottom and rich highs compressed punchy...
    • SoreFingers613
    • Thread
    • amp bias bias drift bias problems crunch channel cuts out jcm 2000 dsl jcm 800 jcm 900 preamp and power tubes preamp problem sound issues
    • Replies: 6
    • Forum: Marshall Amps
  2. K

    Marshall JVM410H bias problem

    Hi I just try to bias my Marshall 410H, on the right is mesuret to 210mV on it’s lowest setting and 194mV om the left on it’s highest setting. I can’t get the tubs to run at a lower mV. is it bad tubes ore are the head the problem? Please help and thanks.
  3. EdHopper

    Plate Current Too High - Red Plating

    I was playing through my model 1987 Marshall 50 watt amplifier when I lost sound. I looked at the power tubes and one tube was "red platting" so I immediately turned the amp off. I replaced the tube and turned the amp on again and that tube also began to "red plate." I found a tube that did...
    • EdHopper
    • Thread
    • bias problems plate current red plate red plating
    • Replies: 59
    • Forum: The Workbench
  4. Chris Rock

    JVM205C Diagnostics (EL34 Issue)

    Hi all: NOOB to the forums. Have a ~2009 JVM205C, no mods, stock, probably original tubes. Was playing with my kids and friends and amp dropped out. Blew fuse FS6 (mains protection) - also known as "high tension" fuse (?). Replaced fuse with correctly sized replacement. Plugged in...
  5. 0

    Replaced Jcm Dsl 100 Board... Still Having Problems!

    I'm a brand new member. I know that this has been done to death, but I've seen this issue pop up on some different forums with no answer. Skip to 3rd paragraph to get to the main problem. Before changing the main PCB, my JCM 2000 DSL 100 was having the classic "bias drift" issues. After...
    • 0caria
    • Thread
    • bias problems dsl jcm 2000 dsl100 new pc board
    • Replies: 112
    • Forum: The Workbench

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