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    noise in power amp

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    bizi

    Posts : 7
    Join date : 2009-01-23

    noise in power amp

    Post by bizi on Sun Feb 22, 2009 2:06 pm

    what is the most likely cause of crackling, popping noise in a tube amp for the first minute or two after start-up. This noise is audible but by no means loud and stops after a couple of minutes.

    Thanks

    Bob Latino
    Admin

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

    Re: noise in power amp

    Post by Bob Latino on Sun Feb 22, 2009 3:03 pm

    Hi Bizi,

    It sounds like a tube issue to me. Try swapping out some newer tubes or some tube known NOT to cause this issue. Is it in both channels ? OR just ONE channel ?

    If you said that this happens after a half hour or so I might have said a problem on the driver board - a bad solder trace that goes thermal and opens up.

    Try swapping out some tubes and let us know what you find ? If you don't have any other tubes try swapping tubes between channels. While your at it clean off the tube pins. Contrary to what some say you CAN use WD40 to clean off tube pins - just wipe it all off before you reinsert the tube. This tube pin issue is more likely to come up on small 9 pin signal tubes like a 7199, 12AX7, EL84 etc. than a larger octal tube which has more pin area to make contact with the socket pins.

    Bob

    danf

    Posts : 58
    Join date : 2009-01-19

    Possibly bad filter caps

    Post by danf on Sun Feb 22, 2009 3:55 pm

    You might find this link helpful:

    http://www.triodeel.com/trouble.html

    bizi

    Posts : 7
    Join date : 2009-01-23

    Re: noise in power amp

    Post by bizi on Wed Feb 25, 2009 11:10 pm

    Thanks for the feedback. In fact it was a noisy output tube and nothing more.

    Bill

    Tube Nube

    Posts : 603
    Join date : 2008-12-06
    Age : 53
    Location : Calgary, AB

    Re: noise in power amp

    Post by Tube Nube on Thu Feb 26, 2009 12:26 pm

    I have a slight static sound, a few seconds after I turn the power on, and it lasts for about 5 seconds. Maybe 10.

    Both with the Dynaco, and again with the Transcendent pre amp, if I turn it on second. Because it happens with both, I'm just assuming that it's normal for tube gear to make a bit of noise as the tubes come to life.

    Alternately, because it's both amps that I assembled myself... ahhh, maybe my technique leaves something to be desired. :-/

    I wonder if I should be concerned, and start swapping tubes around, or can someone comment if this is normal.

    Thanks,

    Brenton

    Bob Latino
    Admin

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

    Re: noise in power amp

    Post by Bob Latino on Thu Feb 26, 2009 1:17 pm

    Brenton,

    Sometimes tubes do make a few sounds upon startup. If both units play OK after warmup I wouldn't worry about it ...

    Bob

    Tube Nube

    Posts : 603
    Join date : 2008-12-06
    Age : 53
    Location : Calgary, AB

    Re: noise in power amp

    Post by Tube Nube on Thu Feb 26, 2009 3:11 pm

    Thanks Bob.

    They sure do play well!

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