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    M125 Power Tubes Mix n Matching

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    jfine

    Posts : 92
    Join date : 2017-06-19

    M125 Power Tubes Mix n Matching

    Post by jfine on Tue Jul 18, 2017 9:50 pm

    Is there anything wrong with mixing brands of power tubes on the M125?

    For example, on a monoblock, there's a left side and a right side, well for biasing anyway.

    If I were to use 2 KT88 Sovtek's on the right bank, and 2 KT88 Tung sol's on the left bank, or even 6550's, if the bias sets correctly, is there a problem? Same goes for using front half and back half, where each bank would have a different tube.


    Another related question, I've found that with small signal tubes anyway, buying a "matched" set really doesn't seem to make much difference, as some circuits might adjust accordingly, and, after some use, they're probably not matched anymore anyhow.

    So is it really so important to install a "matched quad" in the M125? I know these are not small signal tubes. If I don't, so what?

    Dingojazz

    Posts : 50
    Join date : 2010-09-03

    Conventional wisdom says

    Post by Dingojazz on Tue Jul 18, 2017 11:56 pm

    that this is contraindicated  Evil or Very Mad .  

    That said, I have experimented with mixing power tubes in my Mk IIIs and liked the results. (Does that make me a bad person?)

    I typically used homogeneous quads in the IIIs... Genelex, TungSol, Shuguang, etc.  When I happened to try one amp stuffed with Gold Lion KT-88 and the other with Shuguangs, I liked the result, and stayed with it.  For some reason, in my system it works better than exclusively going with one brand.  -I also tried mixing the brands in each monobloc, but didn't find that appealing.  

    Purists will say their nays, but long as the tube type is the same,  particularly in each amp and with individual bias for each tube, I know of no risks to operation.  So why not experiment?  Who knows, you too may like the results.

    K.
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    Peter W.

    Posts : 502
    Join date : 2016-08-07
    Location : Melrose Park, PA

    Re: M125 Power Tubes Mix n Matching

    Post by Peter W. on Wed Jul 19, 2017 8:13 am

    Mpfffff...... Heresy Warning!!

    I have been known to mix brand within a given channel and have up to four different brands of output tubes in the same amp. I have a tester that allows me to match very, very closely such that there is no real risk other than to established orthodoxy in that behavior.

    At the same time all of my tubes are pre-blight, and it is a good chance that many came from the same source whatever is printed on the glass.
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    LeGrace

    Posts : 230
    Join date : 2016-08-07
    Location : Ontario, Canada

    Re: M125 Power Tubes Mix n Matching

    Post by LeGrace on Wed Jul 19, 2017 9:47 am

    I have KT120's in one amp and KT88's in the other and it sounds fine. When you burn up tubes at the rate I do one has to be flexible. I dont have 8 of any one type anymore but do have multiple quads I can switch out.

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