'farting', buzzing tube power amp; broken tube??

[Ali Tait]

Sounds like one of the valves has gone microphonic Anthony explained the best way to check is tap valves with a pen Its really worths speaking to Anthony TD he is a gentleman and really knows his stuff also Lurcher

Lots of valves can be microphonic and still work fine, and you will hear a tapping pen through a lot. Doesn't mean there's a problem with them though. I have had similar problems and it was down to dirty pins. Even just removing and replacing each valve a couple of times could solve it.

[John]

Yes a good pins clean is worth trying, just trying to share something that worked for me when I had a similar issue

[24bit]

thank you Gents,
I just found your topic about cleaning pins and coca cola use
I will def. clean the pins, and contact Anthony as you suggested, swap of tubes won't hurt my amp, they all are old and 'rather low shelf', so maybe it's a good time to invest a bit and have a better sound...
who knows, I will gladly inform what happen.

have a good one