• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

KT-88, KT-77, Russian 6SN7 makes "pops". Should I touch their pin with an iron?

KT-88, KT-77, Russian 6SN7 makes "pops". Should I touch their pin with an iron?

I once read on a forum that Russian 6sn7 Melz (hole plate) tubes are prone to produce "pops" and other distortions, but could be fixed by touching their pins with a warm iron.

I do have few of those Russian 6sn7 and in fact most of them produce pops every now and then.

I also have a KT88 (Genelex UK), new never used, which does the same (produces pops) and when tested swings the needle of the tester around the "?" or "Bad".

And I have one or two KT77 (Genelex UK), also new, that do the same "popping".

Has anyone had experiences fixing tubes by touching their pins with a warm iron? If so, can you tell me more? Should I touch their pins by having the tube staying straight (rather then upside down) to let the solder inside the pins reflow?

Thanks!
 
Usually this "pops" problem happens only with these specific tubes.
With the KT77, if I replace them with a different pair of el34, the problem disappear and the amp is quiet. Even if I knock on the tubes, no noise comes.

Back with the kt77, after a minute or two of use, it starts to pop, and if I knock on the amp itself or any tube (kt77, 12ax7 and 5r4gys rectifier) it makes more scratchy noises...