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Hi all,
I’ve been noticing a tinny noise coming from my tube amp when playing certain notes at higher volume. I recorded a short video to demonstrate the issue: when I touch the 6V6 power tube with the rubber tip of a pencil, the noise stops immediately.
https://youtube.com/shorts/4I4NAQIwTy4
Some additional observations:
Apart from this sporadic metallic noise, the amp sounds normal and behaves as expected.
The noise only appears on specific notes and at higher volume.
Tapping the amp cabinet itself does not produce noticeable microphonic sounds.
I’m trying to understand whether this indicates a microphonic tube, or if it could be something else (e.g., wiring, socket, or other mechanical coupling).
Do you think using a Tube Damper would be effective in this situation? Or is this a clear sign that the tube might need to be replaced? (This amp was made in May 2024 according to the serial number.)
Any advice or similar experiences would be greatly appreciated!
Thanks in advance.
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02-24-2026 10:55 AM
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It's a clear sign the tube needs to be replaced unless you like rattling noises. Dampers might quiet it down for a while and provide some level of future protection but the reality is 6v6's and EL84's, especially newer production tubes, are not very rugged tubes and are generally the sort of amps which require regular valve replacement and service to be reliable if you are using them for something besides home use. If I were gigging a 6v6 amp every weekend, all weekend, at louder volumes, I would plan on re-valving it twice a year to maintain reliability. Look at the bright side, you almost made it two years.
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Just sounds like tube rattle to me. You can pop in another tube to verify but I'd throw a damper on it. You definitely don't need to be replacing tubes twice a year unless something is very very wrong with your amp.
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Us tube guys always have spare tubes. They all have a shelf life. If they begin to sing, simply replace them.
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While it could be a tube, it is in my experience more commonly a mechanical vibration, either in how a tube is seated, rattle in the grill, or even near the amp in the room; it's surprising how often room sounds can seem to emanate from the amp.
So just a matter of eliminating the possibilities.
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Can't identify what you describe in the video. Maybe you could describe it?
- does the sound change character during the sounded note?
- is it twangy, or fizzy or buzzy, or frequency modulation?
Also:
- when did this problem appear?
- how are your tone controls set on the amp?
- remove the tubes and bend the two metal tube base grippers closer together
- put tubes back in and press the grippers down to make sure they grip tight
- if you have a ceiling fan, turn it off so the blades don't Doppler the high notes
- if you have turned the amp off when warm and immediately then turned it on
that is very hard on the rectifier, which if damaged will add various noises
Jazz is very easy on power tubes; in 30 years I haven't needed to replace any power tubes on five of my six Fender tube amps (the exception is the real 1965 Super Reverb which needed it when I got it). What I have replaced are a lot of preamp tubes - modern versions are pretty fragile.
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- remove the tubes and bend the two metal tube base grippers closer together
- put tubes back in and press the grippers down to make sure they grip tight
This addresses my first guess.
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Originally Posted by pauln
In the video you can actually hear the noise if you use a earphone, I can hear it through my AirPods. The noise went obviously away when i touched one of the 6v6 withe rubber of the pencil. The sound is a sort of metallic ringing, and it doesn’t change much during the note. It usually only appears after the amp has been on for about 20 minutes, and mainly on certain notes around D–D# and F–F# and their octaves. Volume at 2-3, Tone controls are pretty standard.
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If the noise is a mechanical resonance that’s vibrating one of the elements or supporting pieces, a silicone damper ring (or two in some cases) around the glass envelope will stop it by damping the vibration and changing the guilty assembly’s resonant frequency and its Q. Originally Posted by DawgBone
Prolonged repetitive vibration and associated motion of an internal part is one of the three most common physical things that cause tube failure. So dampers will increase reliability by preventing that failure mode. The other two, FWIW, are excessive heat and physical shock from dropping / bumping / etc.
I’ve had a few preamp tubes go microphonic on me over 6 decades of tube amp use. But the only frank tube failures I’ve ever had were a 6L6 in my B15N in 1964 and a KT88 in my Prima Luna audio amp about 18 months ago. I dragged Twins, Boogies, etc to about 1000 gigs each without a tube failure (closer to 2000 for the Boogie I used most and longest). As long as you take care not to bang them around, and you make sure nothing has deteriorated to throw output tube bias out of spec, replacing tubes twice a year seems unnecessary IME.
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All my experience is anecdotal but also based on playing many hundreds of shows and seeing quite a few club gigs....the only amp I haven't seen blow a power tube at a gig that wasn't a 6v6 or EL84 was a Marshall Superbass cone with EL34's. I've seen many Deluxes die at gigs, which is why as much as I love the sound of a Deluxe at lower volume shows, I didn't buy one, but I could only afford one amp too, lol. Last rhythm guitarist I worked with had the same issue with his Deluxe as the OP. My current rhythm guitarist loves his EL84 amps and in three or four years he's had 4 or 5 tube related issues at shows, even retubing one of them mid-song. Originally Posted by nevershouldhavesoldit
The little power tube driven amps seem to be the quickest to suffer tube failure due to lack of maintenance. Playing it everyday for two years is a lot of heat cycles....If I was gigging a 6v6 numerous times weekly towards the top of it's power range I would def change tubes a couple times per year to maximize my chances of survival....or carry a 2nd amp in the back of the truck. Also sucks when someone decides to record you and your amp is making a bunch of phantom noises. Been there done that. Proper prior planning prevents piss poor performance. I suppose if you just play at home it doesn't really matter but a tube failure can cause more extensive damage and 6v6's aren't as much money as tech bench fees...
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I just used Sennheiser headphones and have no idea what you are trying to identify.
It helps that you identify the notes with the problem. I does not help to demonstrate with a dense jazz chord that masks softer sounds. Are you using finger vibrato on the F over the chord, and if so why? It does not help to answer that the tone controls are set "pretty standard". You need to make another video or just a recording; if a video do not move the camera, do not touch the tubes, do not play chords, do not use vibrato.
Just play some notes without issues to get a comparison, then play the problem notes.
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I replaced my tube amplifiers with solid state years ago. No more strange noises. Not a bit sorry.
I have spent 39 years as an electronics technician at one of the world's largest research centers. I do know a little about the technology.
As a big band guitarist, I hear no difference in the sound quality between tubes and solid state. Big difference in cost.
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I could hear it w/ my work headset although, with the way it's recorded, the noise is at the very edge of what is audible for me. If you're older than me or your headphones have limited range I could definitely see it being inaudible. All that said, it's 100% just normal tube rattle like you'll find in most small Fender amps. My Princeton does the same thing. Throw a damper on it and forget about it, easy fix. You'll never hear that on a gig. Originally Posted by pauln
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EL84s are often biased at the upper limit in popular amps to add a little more harmonic richness (aka distortion) and increase breakup as the volume is cranked. The Blues Jr is a classic that runs way too hot and loses power tubes as frequently as you describe. The problem is not the tubes - it’s the way the amp is set up. You can dial back the bias for better life, but it’ll stay cleaner and won’t have the same full tone as it reaches the edge. Originally Posted by DawgBone
I bought a Vox Night Train 15 when they came out and used it heavily for several years on blues gigs. With a good metal cage over exposed tubes for great ventilation, it ran cool. These are cathode biased, so it’s not adjustable. But they run close to max and don’t seem to blow output tubes prematurely. H&K Tubemeister 20s and other good EL84 amps have bias monitoring and control circuits that also help tubes live long and prosper in them.
Don’t blame the tube - blame the amp design. Buy smart.
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