BF Deluxe Reverb, reverb tank

[weeping6]

Hello,
I am in the middle of building a replica of the Fender '65 BF Deluxe Reverb (circuit AA763) and my question involves the reverb tanks used in '65 vs. what's available today. I've read here in this forum that the newer Accutronics tanks sound metallic and not as lush. I don't have too much experience with vintage vs. current reverb tanks but I was wondering what you guys would suggest in the way of a good reverb tank that would fit this application?

I've looked for vintage tanks on ebay that someone might be parting out from an amp but they're scarce. Also I thought about maybe using something like an old Hammond tank or something that was built in that era but not straight from a Fender amp. What do you guys suggest?

Thanks for any input.
-David

[Tom Phillips]

David,

I’ve followed the discussions about the Accutronics issues. There really isn’t anything else available. I use them for replacements and have not received complaints from my customers so far.
As I understand it Hammond developed the spring reverb tank style that we use. That business was split off to Gibbs who made the tanks that Fender started with. Then the technology was sold to Accutronics. The Accutronics tanks sold today are the decendents of the original Hammond product. If by “an old Hammond tank” you mean one salvaged from an old Hammond Organ, I believe that you will find that Hammond used a high impedance input transducer which will not work in the Fender style circuit.

Other than finding an old Gibbs tank that is in good sounding condition I think your only choice is an Accutronics tank.

Regards,
Tom

[Enzo]

And anything you hear folks screaming about on the internet is best diluted about 10 to 1. The Accutronics tank will work fine, differences are subtle if you hear any at all. It might seem like more of them are failing than the older ones, but that is very hard to tell. I have always had to replace a lot of reverbs in amps. Espacially the short tanks.

Most folks prefer the long tanks for sound anyway. Be aware ther are two versions of the long tank, the three spring and the two spring. I and many others feel the three spring gives a more complex reverb - lush if you prefer. Both are readily available. the two spring part number starts with 4 and the three spring starts with 9. As in 4AB2C1B or 9AB2C1B. If the specs show slightly different impedances, ignore them, the difference is very minor and the circuit won't care. The 4 and 9 pans are interchangable.

A reasonable source for the things is AES:

www.tubesandmore.com

[Rob Mercure]

Hey Enzo,

This may be a bit off topic but I've had the same experience with the short tanks - but have you noticed how they make a great small chassis for preamps, power supplies or relay boxes, etc.? The steel is of a gauge strong enough to hold a tranny while easy to drill or punch and the side flanges allow a bottom cover plate to be screwed on. While they are almost too shallow for a circuit card I've used several of these for point to point circuitry.

Haven't recycled a long tank yet but most of the blank commercial chassis I've got are either too deep or too wide for some of my crazy conversions so I'll probably find a use for the long'uns also someday. And now that I think of it you a builder could probably cut a suitably sized rectangular hole in a surplus large tank can and then bolt a short one on top if something "deeper" is needed.

Rob

[Enzo]

Oh I always save a bunch of dead short tank pans because they are "just bound to be good for something." But I never get around to using them. They do seem eminently useful, don't they?

I was just looking in a customer's Teisco earlier this evening, and the little reverb unit appeared to be two small single units wired in parallel.

[weeping6]

Well, caught up in a moment of over-zealous ebay hysteria I purchased an old Gibbs reverb tank for $17 that looks to be a 2-spring model. They seller says there's no parts number marked except for a 1122 number. Also, he said he measured i/p and o/p resistance (presumable by a handheld DMM) and got 1732 and 1718 ohms respectively. No specific date was given either.

Maybe I should have checked the required impedance for the coupling transformer I have before buying this tank but I guess I can always sell the tank again if it doesn't work.

It's comforting to hear that about the Accutronics tanks. I'd prefer to have a little faith in their ability to reproduce the older tanks.

-David

[Tom Phillips]

David,
the Deluxe Reverb uses a small output transformer to drive the tank. That design needs a tank with a low input impedance transducer. The higher input impedance of the tank you bought will not work in a Deluxe Reverb amp. However, it should work in some other amps like old Ampegs which drive the tank capacitively coupled from the tube.
We learn as we go.
Regards,
Tom