Home › Forums › Help/Technical Questions › Loss of volume on English Muff’n after tube swap

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  • September 10, 2009 at 6:59 pm #78943
    Xanax
    Member

    I’ve owned an English Muff’n pre amp for a couple of months now and I finally decided to swap the stock 12AY7s for 12AX7s. Unfortunately, instead of boosting my gain, the pedal is pathetically quiet when engaged. I have to turn the volume on the pedal all the way up to hear any sound and even then it’s not really loud. I was forced to put the original 12AY7s back in to solve the problem. Are 12AX7s not compatible with the pedal, or did I buy faulty tubes? The tubes are Electro-Harmonix 12AX7s that I purchased new. Anyone have any thoughts?

    September 10, 2009 at 8:07 pm #101351
    electro-melx
    Moderator

    sounds like you may have a duff valve.

    EHX actually say:

    Supplied with two Electro-Harmonix 12AY7 tubes
    Substitute Electro-Harmonix 12AX7 for more gain/distortion
    Substitute Electro-Harmonix 12AU7 for less gain/distortion
    Experiment with different tube combinations for entirely new tube drive sounds

    so there isn’t a compatibility problem.

    Try one of the 12ax7’s at a time and see what happens (ie 1 12ax7 and 1 12ay7) and see if there is a problem with one of them.

    September 10, 2009 at 9:00 pm #101352
    Xanax
    Member
    Quote:
    sounds like you may have a duff valve.

    EHX actually say:

    Supplied with two Electro-Harmonix 12AY7 tubes
    Substitute Electro-Harmonix 12AX7 for more gain/distortion
    Substitute Electro-Harmonix 12AU7 for less gain/distortion
    Experiment with different tube combinations for entirely new tube drive sounds

    so there isn’t a compatibility problem.

    Try one of the 12ax7’s at a time and see what happens (ie 1 12ax7 and 1 12ay7) and see if there is a problem with one of them.

    Thanks a lot! Turns out that one of the 12AX7s was a dud. Strange, since I bought them as a pair. In any case, the volume issue is fixed. Stupid faulty tube!

    September 10, 2009 at 9:54 pm #101353
    B.Daws
    Participant

    Till you get a new tube try the AY7 in the right spot and the AX7 in the left. You’ll dig it.

    September 11, 2009 at 7:20 am #101364
    electro-melx
    Moderator
    Quote:
    Thanks a lot! Turns out that one of the 12AX7s was a dud. Strange, since I bought them as a pair. In any case, the volume issue is fixed. Stupid faulty tube!

    no worries, glad the plan worked!!

    yeah, it obviously worked at some point otherwise it would have showed up somewhere along the testing stages…. sometimes they just seem to fail for no apparent reason… to be honest everytime I look at a tube closely I wonder how they work at all!! :D

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