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Transducer Specs for Spring Tank for Fisher Spacexpander

Posted: Thu Dec 16, 2004 5:59 pm
by DubSiren
If anyone has a Fisher Spacexpander reverb out there that works, could someone please tell me what the specs are for the transducers on the spring tank? I have an original Fisher spring tank, the transducers need to be replaced, but they are not marked, and this info is not in the schematics. I contacted the "Fisher Doctor" in New York, and he has no idea. I know that some Hammond tanks will work with the preamp, and those are usually marked. Any help will be much appreciated, so I can get my spacexpander up and running again. Thanks so much.

Transducer Specs for Spring Tank for Fisher Spacexpander

Posted: Fri Dec 17, 2004 12:10 am
by Mike Zee
Hey, man, hang in there.... we have couple guys here who do know the unit well, just give 'em some time to see your post. Somebody may help here. <BR> <BR>/respects, <BR>/Mike Zee aka Dr ZEE

Transducer Specs for Spring Tank for Fisher Spacexpander

Posted: Fri Dec 17, 2004 1:45 pm
by Neil C
Well, Accutronics make hammond type 4 spring tanks &#40;which is what the spacexpander tank is - I think Spacexpander just put their stamp on it - mine is orginal and it has the Spacexpander logo on the outside but the inside has a plate on it saying made by Hammond, Type IV&#41;&#41;apparently to the same design as has always been used. <BR> <BR>I think Accutronics are based in the States, but you may have a distributor in your country. The tanks are not expensive, there is a site selling type IV's for &pound;28 &#40;UK sterling&#41; in the UK. I'm not sure if the input and output ohmages are a a match for the Xpander original tank, but I presume they are. I was thinking of getting one myself, because although my tank seems in full condition, I'm wondering if a new one would improve the sound.

Transducer Specs for Spring Tank for Fisher Spacexpander

Posted: Sun Dec 19, 2004 4:53 am
by DubSiren
Thank you so much. There wouldn't happen to be any code numbers on your spring tank, would there? The first would be 4, and the 3rd character, either A &#40;500ohms&#41;,B&#40;2250&#41;, or C&#40;10K&#41;, corresponds to the output impedence. This is what I need. If not, at least you've helped me narrow it down to 3 possibilities.

Transducer Specs for Spring Tank for Fisher Spacexpander

Posted: Sun Dec 19, 2004 12:47 pm
by Neil C
1122-6142 and A 846-109A are the two sets of numbers stamped on it, but I don't think that conforms to what you are looking for.

Transducer Specs for Spring Tank for Fisher Spacexpander

Posted: Thu Dec 23, 2004 7:42 am
by DubSiren
Thanks so much for all the help! The two numbers you gave me must be some Hammond numbers, because they don't correspond to the standard numbering system for spring tanks. However, I was able to determine from the fact of it being a type IV that the output impedence is 10K. I was able to get the proper transducer and now my Fisher rocks again!!! If you plan on getting another tank, make sure you get the right impedence, because there are several type IV's. I don't know what the input impedence is though, I wasn't having trouble with that. Again, thanks so much for the help - DubSiren &#40;The only Dub Chick in my town!&#41;

Transducer Specs for Spring Tank for Fisher Spacexpander

Posted: Wed Jan 04, 2006 8:52 pm
by Dubalator
I e-mail Cal Shuett, from SEPI-GROUP which makes Accutronics spring tanks, and here is what he said: <BR> <BR>"My records show Fisher p/n A846-109A used a Gibbs model L, which is an Accutronics model number 4FB2B2C. This model can still be manufactured, however it will not have the clamp as the original had."

Posted: Sat Sep 13, 2008 1:25 pm
by Neil C
I was just fiddling about with my Spacexpander which put me in mind of getting a new tank again (I never did get a new tank before).
If Dubulator's tank code is right then that would make the output impedance 2250, not 10,000, although if both work then that's all to the good I suppose -
Here's the code system explained:

Does anybody know what the locking system/clamp is that is no longer available?

Posted: Sun Sep 14, 2008 11:11 am
by interruptor
Regarding the locking system: It seems there were reverb tanks around that had a built in damper to lock the springs in place so they would not move around and get damaged during transport.
I have never heard of a spacexpander tank with this feature though..

sources: ... php?t=2862
From a discussion about an ampeg guitar amp with a non-working reverb:
"If anything Ampeg protected their tanks better than most - my V4, and every one I've serviced, has a "reverb lock" that clamps down the tank when not in use - something the Fender, Gibson, et al, never seemed to incorporate."
"take out the reverb and inspect for broken spring and wires inside the tank. the ampeg reverbs sometimes had a lock lever on the side, does your reverb have this and is it unlocked?" ... 66d08e9559
From a discussion about fixing the reverb on a Kustom Guitar 250:
"I have a reverb problem on my guitar 250. It feeds back some and produces little to no reverb. I don't really understand the reverb lock either. What should I do? ....
I believe that the reverb lock should be turned out so it's not tightened down in order for the reverb to be all the way "on." Try loosening the crank and see what happens. There's a rubber "stopper" looking device in there that gets turned into the tank when the crank is tightened. If you
crank the reverb in before you haul the head it will keep the reverb springs from clanking around and being noisy when you drive."

.. ps: Hey Neil, your avatar is really very cute! :grin:

Posted: Sat Sep 27, 2008 4:00 pm
by Neil C
Thanks Interruptor.

I got a new tank (good service from Accutronics).
I can tell you the code above - 4FB2B2C (although 2C will have to be 1C because of the clamp thing*) works - the input output audio levels seem to be the same as the original one.
There certainly is a difference in sound. With both springs (one the new one) there isn't much of the undulating/ripple effect, with one spring tank you get all undulation but no reverbiness. The new one has a more clean, less rusty sound than the original one. I'm not sure if I prefer the old or new one.
The decay time on the new one seems shorter than the orignal - I wonder if I should have gone for the maximim reverb time on the specification.
I also wonder if you need to 'run in' a spring tank to get it to loosen up?

*my orginal tank which has the Fisher stamp on it doesn't have a clamp.

Posted: Sat Sep 27, 2008 9:17 pm
by interruptor
You may know that already: You'll get a longer reverb time if you install the tank vertically.

Posted: Sat Sep 27, 2008 9:26 pm
by Neil C
Yes, that's how I have it.
It seemed to sound better that way when I first tried different orientations when I orignally got my Spacexpander.

Posted: Wed Mar 25, 2009 9:14 am
by ocoughi
Interruptor said:"you may know that already: You'll get a longer reverb time if you install the tank vertically."
in: down and out :up or inverted? personaly i didn't know this before, i thought the sound didn't have anything in common with Newton's gravity laws....
thanks for this info, i'll try it...