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    left channel squeal

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    rfbro

    Posts : 26
    Join date : 2014-12-28
    Age : 61
    Location : Vancouver WA

    left channel squeal

    Post by rfbro on Sat Mar 21, 2015 12:59 pm

    I purchased an assembled St 120 about 2 months ago when I got it one of the tubes red plated I replaced it and the resistor that it popped within the last week I have noticed some squeal that is intermittent coming out of the left channel I would hope somebody would have some knowledge of suggestions what I might do to fix this or can Do to pinpoint The problem..

    tubes4hifi
    Admin

    Posts : 1261
    Join date : 2008-11-30

    Re: left channel squeal

    Post by tubes4hifi on Sat Mar 21, 2015 1:38 pm

    was the tube and resistor that went bad also on the left channel.
    Check all the wiring on the left channel, and re-solder any suspicious solder joints

    rfbro

    Posts : 26
    Join date : 2014-12-28
    Age : 61
    Location : Vancouver WA

    Re: left channel squeal

    Post by rfbro on Sat Mar 21, 2015 2:19 pm

    yes it was on the left channel I did not see anything that looks suspicious down there but I will double check thank you very much

    MontanaWay

    Posts : 767
    Join date : 2014-02-06
    Age : 58
    Location : Cameron, Montana

    Re: left channel squeal

    Post by MontanaWay on Sat Mar 21, 2015 5:08 pm

    looks can be very deceiving....our eyes fool us more than we realize. cyclops
    I would as a matter of course re touch all the solder joints on the sockets and ground connections, can't hurt!
    And whilst you're at it, make sure no components, including on the pcb, show any signs of heat stress, ie darkened, also check for dry solder joints on the pcb as well

    Bob Latino
    Admin

    Posts : 2378
    Join date : 2008-11-26
    Location : Massachusetts

    Re: left channel squeal

    Post by Bob Latino on Sat Mar 21, 2015 6:52 pm

    rfbro wrote:yes it was on the left channel I did not see anything that looks suspicious down there but I will double check thank you very much

    Hi Robert,

    Just to eliminate the fact that a TUBE is at fault.

    1. Try swapping FIRST the two output tubes from one channel to the other to see if the problem moves to the other side.

    2. Try swapping the left and right driver tubes to see if the problem moves to the other channel.

    3. Swap the center driver tube for either of the other driver tubes to see if the problem moves to the other channel.

    If it proves to be a fault of a tube, I can send you out another tube at no cost.

    If it is NOT a tube at fault > Can you post a photo of the inside wiring of the amp in question so that we can look at the inside of the amp ?

    Bob

    rfbro

    Posts : 26
    Join date : 2014-12-28
    Age : 61
    Location : Vancouver WA

    Re: left channel squeal

    Post by rfbro on Sat Mar 21, 2015 7:50 pm

    thank you for your response Bob I will do that but it won't be till probably Monday evening for I am away at work and am out of townout of town

    deepee99

    Posts : 1260
    Join date : 2012-05-23
    Location : Wallace, Idaho

    Re: left channel squeal

    Post by deepee99 on Sun Mar 22, 2015 1:02 pm

    fbro,
    I would also check the tensions on your tube sockets, sometimes the individual pin-holders can get a bit loose (over-sized) and break contact. That's an easy, if a bit tedious, fix with a jeweler's screwdriver. Also, a little De-Oxit on the socket-holes and the tube pins themselves never hurts.

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