Accutronics swap for Vox AC30 Reverb tank

[the rollerdoor]

I just picked up an Accutronics reverb tank, which is the same dimensions as the Beldon (AC30) tank.
Two RCA jacks in for input (red) and output (white). Damn thing doesn't work. When I shake the unit, the
springs rattle through the speaker, but no reverb sound atall with the guitar when played. Dry as a....
Any of you fine folk know what is going wrong here? Seems like the tank and amp aren't "talking".

[øøøøøøø]

There are more to reverb tanks than meet the eye.  There are many different models with different specs, input impedance, output impedance, etc.

Maybe you should do some research and make sure the tank you got will 'talk' to your amp properly.

[the rollerdoor]

There are more to reverb tanks than meet the eye.  There are many different models with different specs, input impedance, output impedance, etc.

Maybe you should do some research and make sure the tank you got will 'talk' to your amp properly.

This seems to be the case. I haven't really found a matching recommendation for AC30's as yet.
I just took a punt, may have lucked out here...I'll go to my guitar tech, see if he can switch some parts
so it works.

[Tonebender]

Maybe you should do some research and make sure the tank you got will 'talk' to your amp properly.
[/quote]

How can you tell?
I've been thinking about a putting a new tank in my Ampeg Jet II, (maybe a 3 spring?) but can't find any info on what input/output impedence it is, nothing on the original tank or on the internet.
Any ideas?

[ohm-men]

I had a simelar expirience with a used SF Bandmaster Reverb a few year back. The reverb never sounded right for some reason, even though it had a Accutronics long spring tank in it (in the stock black Fender bag)
A few month later a friend sold me a accutronics tank from his Quad reverb for really cheap. So I took out the one from the Bandmaster and noticed that it looked very simelar, though it had a somewhat different code. On the inside where the "send" jack was located I noticed a different resistor?, the whole thing just looked different inside at the end of the plug. So I swapped the tank with the one from the Quad reverb and wow, what a difference. The typical "wet" "boingy" reverb usually assosiated with those SF Reverb heads. So I guess someone put in a wrong tank in my BMR.

It seams you really need to check the "type" and "code" when replacing a tank. I think there was only one or two different numerals in the code/type of accutronics tanks.

Though, I also think that the way a Vox reverb works is entirely different then that of a fender. Just different technology?

[the rollerdoor]

I want the fender reverb outboard box sound..that's why I bought it. I remember reading on sweetwater someone
swapping an accutronics for the Belton Vox unit. It apparently worked. So, off I went. It looks to be perfect, as if the Belton is a copy of
the Accutronics. Like I said I can hear spring noise only through the speaker, but no effect.

NB Just chasing the fender reverb sound, not a fender amp sound. I am a Vox person.

[øøøøøøø]

I want the fender reverb outboard box sound..that's why I bought it. I remember reading on sweetwater someone
swapping an accutronics for the Belton Vox unit. It apparently worked. So, off I went. It looks to be perfect, as if the Belton is a copy of
the Accutronics. Like I said I can hear spring noise only through the speaker, but no effect.

NB Just chasing the fender reverb sound, not a fender amp sound. I am a Vox person.

You won't get the fender outboard sound from using an accutronics tank in a Vox amp, even if you can get it to work.

The Fender reverb is a totally different design.  The actual springs/pan is of secondary or tertiary importance to the rest of the reverb circuit.  The Fender outboard design is a 6K6 driven, transformer coupled spring reverb unit with controls for how hard the springs are hit and the amount of wet/dry mix, as well as a tone control across the springs.  THAT stuff is what defines the sound of the unit.

The best way to get that sound for a reasonable cost would be to get a used reissue tank and maybe replace the 6V6 with a 6K6 if you want.

[ohm-men]

+1 on the RI with 6K6 and perhaps the tone cap mod.
Been playing one for the past 3 years now. Never looked back.

I also think now is the time to pick one up as a lot of gear is being unloaded, so good deals are to be had.

[the rollerdoor]

Thanks guys. That's really interesting.. I had a loan of one of these below (fender tank) for a few months and I may have fallen in love with it.
I think it may be the only way to go...eventually. They sound bloody fabulous.

[øøøøøøø]

Fender outboard unit is cool.  Incidentally, I believe they are copied off of a reverb from old Hammond organs like the A-100.  Wouldn't swear to that though.