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    Bad Tube???

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    Phrasemaker

    Posts : 34
    Join date : 2015-05-24
    Location : Essex

    Re: Bad Tube???

    Post by Phrasemaker on Fri Jun 12, 2015 12:33 pm

    It is a transistor type, metal–oxide–semiconductor field-effect transistor to be exact which wouldn't be considered a user replaceable consumable item like a tube. If one of those is faulty it'll be the manufacturer who has to sort it under the terms of your guarantee.
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    gravydb

    Posts : 193
    Join date : 2014-06-22
    Location : PA

    Re: Bad Tube???

    Post by gravydb on Fri Jun 12, 2015 12:45 pm

    Don't forget it could be a bad pre-amp tube as well. A lot of those noises on your video remind me of failed pre-amp tubes in days of yore Smile

    stugotz74

    Posts : 52
    Join date : 2015-04-21

    Re: Bad Tube???

    Post by stugotz74 on Fri Jun 12, 2015 12:47 pm

    yeah. they are going to give it a good check out. they were very nice guys to talk to.
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    namklak

    Posts : 185
    Join date : 2015-01-30
    Location : Denver, CO

    Re: Bad Tube???

    Post by namklak on Fri Jun 12, 2015 1:22 pm

    I'm willing to bet $.38 that tube 2 is bad.

    Tubes are a little like strings, but I think the USA H&K distributor will take care of the tubes.
    A MOSFET (which was described very accurately above) is a semiconductor - semiconductors have WAY MORE (aka longer) reliability than tubes. But of course they can die...

    TAD tests their tubes and classifies based on noise and other params. And so do most other distributors. TAD sells the same tubes for more because the supposedly test the crap out of them. But that still won't catch late infant mortality like what you had...

    And thanks for posting that video - that was very enlightening...

    stugotz74

    Posts : 52
    Join date : 2015-04-21

    Re: Bad Tube???

    Post by stugotz74 on Fri Jun 12, 2015 1:49 pm

    you are welcome. they were going to mail me tubes but once they saw the video he thought it might not be tubes. once i swap the tubes out i'll know for sure. I think they will replace the tubes anyway.

    stugotz74

    Posts : 52
    Join date : 2015-04-21

    Re: Bad Tube???

    Post by stugotz74 on Sat Jun 13, 2015 1:32 pm

    I replaced the 2 inner EL84 (its all my buddy had) same noises, maybe a little less than before.
    swapped out all 12ax7, no change. i busted a tube taking them out so i cant swap the outer ones out...
    Amp is packed up and going to distributor monday.... sigh..
    Here is a vid of the new blinks on TSC
    https://youtu.be/4ijtvxssp0k

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