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    pre and power amp small signal tubes help


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    Join date : 2014-12-28
    Age : 63
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    pre and power amp small signal tubes help

    Post by rfbro on Mon Apr 04, 2016 12:31 am

    First question in my SP9 pre is it important to use all 4 12ax7 that are balanced   witch 2 slots are inventors the ones to the front or rear...
    in my st 120 is it more important to have a balanced tube in the center...any info would be appreciated..
    i do have a variety of ax7 au7 that are balanced  and many that are un balanced by as much as 4 points as tested on an orange tube tester this link should show what i am working with  Bob B

    Posts : 1463
    Join date : 2008-11-30

    Re: pre and power amp small signal tubes help

    Post by tubes4hifi on Tue Apr 05, 2016 8:56 pm

    not very important at all, each tube used in the SP9 uses one section for gain, and one section as a cathode follower.
    If you had several tubes that were all poorly balanced, with more gain (all on the same side), then one channel might be maybe 10% louder than the other,
    but with the signal running thru 4 triodes on each channel, likely the law of averages is on your side. If you wind up having to constantly put your
    balance control to the left or the right, then you aren't very lucky.
    Also, the tube tester you are referring to is partially designed to run tubes at various points up to absolute maximum gain.
    Guitar amplifiers are purposely made to overdrive and distort the signal, something that is never done in hi-fi audio.

      Current date/time is Fri Jul 20, 2018 12:46 am