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

[24bit]

Hello,

If it's posted in wrong subforum - my apology; admin please remove it to proper one
I have problem with power tube amp which has started about 10 day ago.
The amp after 10 min since it's on, starts 'farting' and buzzing, making distorted noise in both channels...very ugly and scary
it dissapears after about 40 min (within this 40 min it happen from time to time, and lasts for few sec)
Funny thing is when I stomp on the floor, it stops....like it was a cable issue, but it's not I checked it
Could it be a simple tube problem (amp is over 10 years old) ?
How to spot the issue if I am not a diy'er and doesn't have any tools except soldering iron (for making cables) ?

many thanks in advance

[The Vinyl Adventure]

my amp was doing this ... anthonytd told me what it was but i cant remember what he said ... was one of the valves on its way out i think

[electric beach]

Hi.

I would echo Hamish's comment; had the same thing myself recently with a valve power amp - crackles, pops, distortion on start up which reduced after warm up. Could tap the valves and get it to stop sometimes. It did prove to be a driver valve breaking up and a new pair (£20) solved the issue completely.

[colinB]

I had the same problem, changed the valves and sounded better than before.

[The Vinyl Adventure]

Try contacting Anthony at tube distinctions ... He posts on here once in a while, built my amps for me, in fact he has built amps for a few people on here ... He knows his stuff and I'm sure will be able to help

[24bit]

Thank you guys, I really appreciaty your help,
I've noticed that taping thing too....(when I tapped amp i dissapears or sometimes make a huge noise)..

btw how to contact Anthony ? email, web address ?


thanks again

PS. I have 4x EL84 and 3xECC88 in my power amp (funny odd number...) if I want to change all of them it will be pricey...
is there any way to find ou which one (or more then 1) should be changed ?? any other place to buy valves then ebay ?

[Ali Tait]

Before spending money on valves I would thoroughly clean all the valve pins. Dirty pins can cause all sorts of problems.

[John]

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

[24bit]

thank you again,
I managed to open amp to try to find 'visually' which tube could it be - all tubes looks same, shining:)
and since then amp completely stopped doing those noises....
cheeky bugger, isn't it ??:)
anyway it has to be something with temperature, for my simply brain deduction:), since the problems stopped completely without the cover of amp
I did tap tubes with a pen and they seem to be dead quiet (no microphonics)

I will email Anthony (got his website) for sure

again big thanks

[Ali Tait]

It may well be a valve, but it could equally be the pins. Worth a try as it's free to fix!

[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