new reverb tank into a silvertone twin-twelve head.

[25orsixtwofour]

just as the name suggests... the only thing is, how do i get the right reverb unit, for a plug and play scenario? i got the schematic someone drew up, but i don't know how to decipher the diagram enough to find the reverb circuit so i can order the right reverb tank.

someone please help!!

[Bill Moore]

If you have the old tank, a few measurements should give you enough info to go to the Accutronics site, where they have a good chart to find your unit. Measure input, and output resistance, and whether or not the input, and or the outout is grounded to the chassis. The other numbers/letters pertain to the mounting positions, and delay time.

[Earl Norton]

look here.

Accutronics Reverb by Sound Enhancement Products, Inc.

The input and output impedence can be determined by the color of the transducer bobbins.

Accutronics Reverb by Sound Enhancement Products, Inc.

[Bill Moore]

I didn't think the original tank would be a Accutronics. My old Airline has a Hammond, and my 70's Rickenbacker has an OC Electronics.

[J M Fahey]

Sorry to bring bad news, but no Accutronics/Hammond/Gibbs , not even a modern Belton will fit there, because all above mentioned have electromagnetic drivers and pickups, and Silvertone's were homemade piezo units.
Just to understand what it means: all modern reverbs are inductive and love current drive; those piezo ones are capacitive and need tons of voltage; that 6CG7 driver can provide around 200V RMS into a high impedance load.
If you have the original unit, I'd *love* to see a couple pictures.
*Maybe* I could even guide you to re-build it, If i had enough details, nothing promised of course.
Anyway Silvertones were famous for their good sound and horrible reverb.
You may buils some version of Fender-type reverb, even a transformerless Ampeg type one, but it involves major surgery.

[Bill Moore]

Yeah I did a search, there was quite a discussion back in 2004.

[25orsixtwofour]

link?

[25orsixtwofour]

okay so I redrew the reverb section of the vt-22 that you'd have to build into the 1484. I didn't change any values so if any are different, they're a typo and you should tell me so I can correct it.

The only thing that would need to be figured out is the values of the resistors with the question marks in order to get the voltage at the plates what it should be. The necessary voltage (as given on the VT-22 schem) is in red.

I believe the 'IN' would be PIN 7 of V2 (connected to the wiper of R21)

I'm not sure on where the 'OUT' would be connected.

found this here... was a thread on putting an ampeg reverb circuit into a 1484 (see diagrams) http://music-electronics-forum.com/t13771-post126888/

would it work? i'm not afraid to pull the thing apart...

[Enzo]

I have actually repaired those pitifull piezo revern units. A serious pain in the ass. And when it is back working 100% it still sounds like crap. Sorry. I find that the piezo elements I had access to were double sided, in that there was a central disc with piezo on either side. the outsides were wired parallel. Unfortunately the discs used in the Silvertone were a simple sandwich of piezo. Point being I could not just slip a new hunk of piezo into the old clip. I had to re-engineer the clip for the new wiring scheme.

Adapting the AMpeg type circuit seems like the best idea to me also, but then you have to decide where to mount the new pan. It won't go where the old one was.

[25orsixtwofour]

i plan on redoing the entire chassis, and will make the total dimensions a bit deeper, depending on the length of the reverb tank needed, now if i could only figure out which one i'll need...

[Enzo]

You won;t be plugging any commercial pan into the circuit as it sits. You will need to rewire the drive circuit - looks like the 6CG7 V5. You would then chose the pan suited to whatever scheme you chose. I might like the AMpeg scheme, driving a high Z pan (4FB2C1B or similar) pan. But if you added a small reverb drive transformer circuit ala Fender, then a lowZ pan would be the choice (4AB2C1B)

[cowboy]

Me and my friend once made a piezo reverb out of a singing birthday card that we inverted and a sheet of metal we found at the scrapyard, and that pretty much sounded like a 1484 reverb...

[25orsixtwofour]

Sorry to bring bad news, but no Accutronics/Hammond/Gibbs , not even a modern Belton will fit there, because all above mentioned have electromagnetic drivers and pickups, and Silvertone's were homemade piezo units.
Just to understand what it means: all modern reverbs are inductive and love current drive; those piezo ones are capacitive and need tons of voltage; that 6CG7 driver can provide around 200V RMS into a high impedance load.
If you have the original unit, I'd *love* to see a couple pictures.
*Maybe* I could even guide you to re-build it, If i had enough details, nothing promised of course.
Anyway Silvertones were famous for their good sound and horrible reverb.
You may buils some version of Fender-type reverb, even a transformerless Ampeg type one, but it involves major surgery.

soooo, Here you go. thanks for the offer to help. what I'd like to do is put in a more fender-like reverb, but i really will do whatever to keep the drive and recovery the same, so i don't have to modify the chassis a whole lot. This will be my first attempt at major work on an amp, so any pointers in that way will be super helpful.






the previous owner did the painting, that'll come off. the knobs will also be changed out to more classic looking brushed aluminum ones.

[Sweetfinger]

This mightbe a suitable candidate for the Belton Digi-log reverb. Space is at a premium in the 1484.
01 - More Info for item P-RBTDR-1H-L
maybe drive the unit from the cathode of the 6FQ7?

[J M Fahey]

That sounds interesting.
I've never seen one of them live (yet), if somebody tests them , please post your experience here.
In theory it should fit there, being an independent module which needs, what, 5 volts?.
Easy to get on any tubed amp