Installing Tube Dampers correctly

[calgara12]

Hey Forum :]

My Vox AC30C2 has this metallic rattle when i hit certain notes, i figured its a tube making these sounds and I've read that tube dampers could solve this issue, so i went ahead and ordered some of those. When they arrived i immediately opened my amp and then i saw those metal retainers that are tightly fit around the tubes.



So here comes my question, how do I install the tube dampers, or can i even install them with those metal retainers?
I dont have much knowledge when it comes to tube amps so please forgive me! But i really hope someone can help :]

I tried to squeeze the dampers in between the retainer and the tube.



Would this be the correct way to install it?

I'd be glad for any kind of advice on how to solve my issue

Thanks in advance guys :]

[52 Bill]

Welcome to the place.

Before you fix something, it is best to find out what is wrong.

Did you tap lightly on the tubes with something like a pencil to see if any of the tubes made noise when they are mechanically vibrated?

Sometimes the internal elements of the tubes change dimension after having been heated and cooled a number of times. Sometimes this will allow the parts to vibrate and act like a tiny microphone. When this happens the tube can make noise through the amp, causing the symptoms that you have. Microphonic tubes are a fairly common occurrence and can happen will nearly all of the tubes in your amp.

If after tapping on the tubes, you find one or two noisy ones, you could try switching the positions of the noisy ones, because sometimes they will make less noise in different circuits. Of course this only applies to tubes with matching numbers in the amp. If they still make noise, you have the option of adding silicon dampers like the ones that you have or replacing the tubes with new quieter ones.

I've used the dampers on tubes that owner's felt were important to keep using, but I didn't find them to be all that helpful. The way that you have them installed is about the only way that you can use them.

[calgara12]

Welcome to the place.

Before you fix something, it is best to find out what is wrong.

Did you tap lightly on the tubes with something like a pencil to see if any of the tubes made noise when they are mechanically vibrated?

Sometimes the internal elements of the tubes change dimension after having been heated and cooled a number of times. Sometimes this will allow the parts to vibrate and act like a tiny microphone. When this happens the tube can make noise through the amp, causing the symptoms that you have. Microphonic tubes are a fairly common occurrence and can happen will nearly all of the tubes in your amp.

If after tapping on the tubes, you find one or two noisy ones, you could try switching the positions of the noisy ones, because sometimes they will make less noise in different circuits. Of course this only applies to tubes with matching numbers in the amp. If they still make noise, you have the option of adding silicon dampers like the ones that you have or replacing the tubes with new quieter ones.

I've used the dampers on tubes that owner's felt were important to keep using, but I didn't find them to be all that helpful. The way that you have them installed is about the only way that you can use them.

Thank you so much for your reply! I'm really grateful, cause im extremely new to this! :]

Yeah i've tried taping them with a pencil, two (out of 7) tubes seem to be making this noise. Ill try to swap them around and equip them with those silicon dampers. I hope this solves my issue, and if it doesnt i just have to get new tubes.
If i can't fix the problem with the dampers do i have to replace all tubes at once, or just all of ther power tubes ( 2 of the power tubes are making the problem), or can i swap them out one by one if i buy an exact replacement?

thanks in advance :]

[52 Bill]

Oh, so the problem tubes are EL84s. They will become microphonic, but they usually don't get better in different sockets.

The power tubes get very hot in an AC30, but I guess that it depends upon what bias setting you are using. The tube dampers may not like the heat from those tubes, so keep an eye on them until you are certain that there is no reaction from the temperature.

As far as replacements, all four tubes work together and should be replaced as a set if possible. I do know people that will replace them one or two at a time with no real problems, but YMMV.

[calgara12]

Oh, so the problem tubes are EL84s. They will become microphonic, but they usually don't get better in different sockets.

The power tubes get very hot in an AC30, but I guess that it depends upon what bias setting you are using. The tube dampers may not like the heat from those tubes, so keep an eye on them until you are certain that there is no reaction from the temperature.

As far as replacements, all four tubes work together and should be replaced as a set if possible. I do know people that will replace them one or two at a time with no real problems, but YMMV.

I've tried to turn the amp on with the dampeners, and it seemed to have fixed the problem, but after a few minutes of playing i noticed a strange smell. Looks like the dampeners were about to melt so i took them off. I guess i just have to replace the tubes that produce the rattle. Again, thank you for your help. :]

[Mick Bailey]

EL84s are just about the hottest running tubes in guitar amps and they're pushed way beyond their design specs to achieve the sound we like. Even if you got hold of some O rings that could stand the temperature, they further hamper the heat getting away from the tube and in a Vox they need all the ventilation they can get. 'tube rattle' is very common, especially so in combos where vibration acts on the tubes directly. Sometimes a set of tubes that rattle in a combo work fine in a head.