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  • #16
    I don't know... depending on the actual amp, to my ears, EL34s always seem to sound great to me when they are idling at around 16-18 watts each.
    But I don't like to say a specific idle current value because it also depends on the OT Zed, measured B+ at the plates and screen voltage.
    Normally you would see a pair of EL34s at around 3200 to 3400 ohms and the screen voltage just a little less then the plate supply voltage.
    With lower plate voltages and cathode biasing, I actually like the PA to be running a little higher in primary Zed.
    But this brain is connected between my ears... even if I have more experience then you, I can't really tell you what is right with respect to overall tone ... especially if you've hit on something that is more of what you want.
    Bruce

    Mission Amps
    Denver, CO. 80022
    www.missionamps.com
    303-955-2412

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    • #17
      Well, i found a big part of the issue...cathode bias. i should say it was a big part of all my issues. I converted to fixed and now it's far better sounding. I could gig with it right now in fact and i'm pretty sure the tone would be better than most production amps i've owned. But i need to know how to bias it right. I used the 2204 schematic in the link below and set the DCV at the resistor junction to -40VDC because i recall that being a approximate setting from my old jcm's. Can you steer me in the right direction to do this right? I tried 1 ohm R's from cathode to ground and measured across them but couldn't get a reading that was anything near right. (got something like .007VDC at most with extreme setting of the pot)

      http://www.schematicheaven.com/marsh...l_50w_2204.pdf

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      • #18
        How did you connect your 1 ohm resistors ?

        Paul P

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        • #19
          One per tube, connected to pins 8 and 1 to ground.

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