Tube noise - help needed.

[kungfujews]

Sorry if this sounds like a stupid question to any valve veterans out there, but one of my valves (6L6) in my MK4 makes a rattly/vibration noise in response to bassier frequencies...It basically sounds like something mettalic rattling about inside. This stops when I place my finger on the bottom of the valve - I know I shouldn't, and I do use a cloth to keep my finger covered!! The valve doesn't appear to be loose and as far as I can tell the valve looks to be burning OK - I also can't see any spotting or loose debris inside- and other than these low end frequencies it sounds ok too. I could ask our singer to stand behind my amp and keep his finger on the valve - but I've a funny idea he won't go for it! Any ideas??

 

[94Tremoverb]

Replace it...

This is a pretty common problem with power tubes in combos, and there's really nothing you can do about it other than try another tube. If you think it's annoying to have to do this when it works fine electrically, wait til it happens with an expensive NOS tube .

Keep it as a spare because it will get you through a gig, rattle or not.

 

[kungfujews]

Thanks Tremoverb, I think I'll replace it - but I'll have to wait until next month - pay day's been and gone and blew my spare cash on a spax7 and 12AX7. I'll try and get a matched pair from mesa then I'll have 2 spares

 

[jpdennis]

Thanks Tremoverb, I think I'll replace it - but I'll have to wait until next month - pay day's been and gone and blew my spare cash on a spax7 and 12AX7. I'll try and get a matched pair from mesa then I'll have 2 spares

I had that happen on my Mark III. So I went to Class A and made sure I had two good tubes in the V6 & V9 [seems this early Simulclass can still hold 6L6 tubes in all 4 power sockets when needed as well]. My tech said that I lucked out as hoping to stretch the tube while going full bore could have made the thing more costly had it red plated and took out several other components :x .

Dennis

 

[kungfujews]

Cheers Dennis - I'll go class A and give it a go...don't fancy paying out for unnecessary parts! These things can be pretty costly to keep on top of - but they're worth it!