Reverb Tanks

[Chuck H]

Well FWIW the tanks Fender sells as OEM replacements look to be a Belton or Accutronics. Same people now but I don't know if there's any difference in the tanks as marketed? They certainly look the same inside. It's been many years since I had to buy a reverb tank and things change all the time. Perhaps the Accutronics offerings are worth a look? Fender does have a reverb reputation to uphold with their reissue offerings so their choice is something to consider I think. And FWIW my reverb tank troubles have always been with independent vendors and I always suspected that I couldn't get a good tank because big amp manufacturers, like Fender, were getting the good ones and the aftermarket vendors were selling the leftovers or returns from those manufacturers. I never tried buying a tank from Fender though. You'll pay a little more but they are probably "select" or "selected" to some degree. Fender certainly couldn't be bothered with returns of bad tanks from authorized repair shops and probably wouldn't risk the same bad rep that several aftermarket parts vendors have to stave off all the time. So, the way I imagine it the part Fender sells is represented by Fender to work and sound to their standards as a replacement. Worth a shot I think.

[Mark Hammer]

Aren't there still Accutronic tanks still available?

[52 Bill]

In the olden days, you could order replacement transducer assemblies from Fender. This would include the entire coil, spring hooks, etc. You would just drill out one mounting rivet and screw down the new one. Then all you had to do was to hook the old springs up and away you go. Then in order to keep the springs from coming loose they started to epoxy the springs to the hooks. This made replacing the transducer assemblies harder to replace in the field.

Before Accutronics was sold to the Koreans, the old factory would sell parts or repair broken tanks for a reasonable fee. I would assume that by now all of the old parts have been used up or sold off. You might try and contact them and ask if they still have old style transducers available. I still rebuild old tanks with old parts when I can.

As for the new tanks, sound wise I personally find them all to be quite different from the old tanks. The reverb sound if fuller, darker and richer in depth. They really sound nothing like old thin, bright tanks that I remember as a kid. I can usually tell if the tank in an old BF Fender amp has been replaced with a new one, just by listening to it.

[Chuck H]

If I remember correctly (it was a while ago) Accutronics had a little QC trouble in the end and then just sold the company (or name and rights?). They couldn't use the special compound that served as the damper in their transducers because it was too toxic to be legal and they weren't able to find a suitable replacement. The original damping compound, much like the electrolyte in capacitors, could last for ten years or fifty years depending on all kinds of factors. This is the info I remember reading at one time or another from back in the day. Take this with a grain of salt as I can't remember my sources. But what this tells me is that NOS Accutronics tanks may be no better than NOS electrolytic caps. Which would also negate salvaging transducers from the original tanks. YMMV but I've had the opportunity to try out one NOS and one barely used UOS (used old stock) Accutronics tanks and they were both too microphonic to be useful. I also read that Jerry Garcia was so fond of one of his old Accutronics tanks that went microphonic that he had his tech remove it from the amp and keep it isolated so he could keep using it. Which sounds like some long, noisy leads to me but why would anyone make that up?

[g1]

I'll just put a reminder here about the weird new tanks masquerading under the original Fender part # 064063, which are Ruby/Belton RRVL2AB1C1BV4 (reads 50 ohms DC resistance at output coil).
See discussion here: https://music-electronics-forum.com/...reverb-changes

[Helmholtz]

I don't buy that "suitable damping material no longer available" story.
What I found in the brass tubes is a simple rubber disk (see part "52" in the patent) with a tiny center hole that centers the suspension wire.
Certainly also provides some damping - especially regarding unwanted lateral vibration, probably less so regarding the principal (torsional) vibration.
Can't believe there's no substitute.

Many (me including) still love the sound of their original BF tanks.
But the reverb of my '63 Vibroverb RI sounds just as good.

When a tank gets microphonic the reason is most likely a loose transducer coil and/or too rigid tank mounting.

Original Hammond tanks also had black damping foam stripes glued on top of the pan as well as foam attached to inside of the suspended aluminum tray to reduce shatter noise.
But while lowering the risk of acoustic feedback.none of these should have a direct effect on reverb sound.