Tube Dampeners in Fender '68 Princeton Reissue

[tomvwash]

Wondering if the vibration in my amp is the tube filament--glass like noise. I thought it was the cage or even the speaker, but maybe the tubes? Due dampeners help with this, or compromise the tone. Thank you for any insight.

[SoftwareGuy]

With the amplifier on and the volume turned up, tap on each tube with something (not your fingers, the tubes are very hot). A pencil with a rubber eraser would do.

It you hear the tapping coming out of the amplifier, the tube is sensitive to vibrations (sometimes called microphonic) and can be the cause of weird sounds coming from the amplifier. Consider replacing the tube and see if it fixes things.

[Sam Sherry]

I bought 1 1/8" silicon o-rings at the hardware store -- 2x for each power tube.
A dollar later, I determined that they were better than nothing but not a total solution, and that I could hear no effect on amplifier tone.

IME 6V6s tend to ring in small combos such as Princetons and Super Champs.
You Mileage May Vary.

[DawgBone]

I went through some hair tearing moments about a year ago trying to chase a couple phantoms out of two Twin Reverbs. I was doing studio work and EVERYTHING was coming through into the recording.

Check tubes as software guy recommended. I honestly think tube dampers are mostly BS. The sleeves with the springs should eliminate that problem but I suppose a noisy tube is a possibility. Some other things to check:

Baffle board tightness. Make sure screws are tight. They have a way of loosening up.

Speaker tightness. Make sure nuts are snug. You ain't gotta crank on them but they should be checked in a cross hatch pattern so they are evenly tightened.

Is it possible the speaker is reaching the end of it's life? Weird noises from speakers on the way out can be intermittent.

Speaker gasket. Is it in good shape? Is it possible cone edge is rubbing against baffle at higher volumes? That's kind of a low watt amp so if you are gigging you might be pushing it harder and that could be happening. You could cure it by sourcing some cork and adding it, giving some more room between the baffle and speaker edges.

Baffle board flex. How heavy is the speaker you are using? Can you flex the board by pressing at the top of it, right underneath the amp chassis? This was one of the big noisemakers for me, and the finish on the underside of the chassis was worn through. I solved it by screwing a 1x1 wood strip at the top of the baffle. There was just enough room to add it and still clear transformers/chassis. Then I used some tape on the underside of the chassis above baffle so any movement after that point was both minimized and muffled down by the tape. I was using heavier speakers, JBL's, EV's, and some very heavy eminences which resulted in a lot of movement (and they are both relatively new mojotone pine baffles.)

Lastly, if it's still happening I'd have a tech go into the amp and check everything. Ultimately I had a loose choke replaced, and the input caps on both amps fully changed out, replaced cathode bypass resistors, and had most of the solder joints reflowed. Probably dumped $500-700 into maintenance and a new set of speakers smh, lol.

Those were the steps I took. Total hassle but what other choice do you have besides to get rid of it. Good luck!

[olejason]

I have the same amp and mine definitely has a decent amount of tube rattle. I have dampeners on the tubes which does help and keeps things quiet enough it isn't noticeable on gigs. If I'm just sitting in my living room practicing I can still hear some rattle on some notes.

[tomvwash]

I have the same amp and mine definitely has a decent amount of tube rattle. I have dampeners on the tubes which does help and keeps things quiet enough it isn't noticeable on gigs. If I'm just sitting in my living room practicing I can still hear some rattle on some notes.

Good to hear, in a bad way. Time to sell, and someone else can address it.

[MHeld]

The easiest way to get rid of a rattle in an amp is to play with a drummer.

good luck hearing anything at all.

[tomvwash]

Good to hear, in a bad way. Time to sell, and someone else can address it.

Actually, Softwareguy's note proved to be on point--two tubes with that glass vibration noise. I will replacements, worth the try--I love the amp. Thank you for the suggestion.

[2bornot2bop]

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