Reverb replacement

[pdavis68]

I have an old Ace Tone Elite amp (~5 W Japanese amp from the 60s). The reverb tank is physically defective and I want to replace it, but I have no specs on it and I've never seen one like it (it's about 3/4" x 3/4" by 10", so very tiny). The reverb is connected at one end (not directly, but via a cap) to the plate of a 12AX7 tube. I haven't checked the plate voltage. The other end goes through the reverb pot and into the grid of a 6AV6 triode.

Based on this can anyone tell me what impedences I'd be looking for in a reverb tank?

 

[sreten]

Hi,

Probably easier to fix whatever is broken in the reverb.

rgds, sreten.

 

[pdavis68]

It's really, itsy bitsy, delicate piece of metal that's torn. I doubt I could find a replacement part and there's no way to repair it.

 

[JonSnell Electronic]

You could remove the springs and tranmitter/receiver from a current tank and insert it in the old box.

 

[pdavis68]

Here is a photo of the reverb. The red circle is where a tiny sliver of metal is torn. It's almost as thin as foil and I don't know how to secure a new one even if I had it. The work would be really delicate and I doubt I have steady enough hands to do it, even if I knew how.

 

[JonSnell Electronic]

Have a look on ebay for reverb tanks. There is a whole host of different sizes available. If you find one that fits, remove the old one and fit a new one, complete.

 

[pdavis68]

I'm fine with one that's physically bigger. There's room in the case. I'm just wondering if I need to be concerned about input and output impedence values. I'm fine with paying $15-20 for one of the ones at Antique Electronic Supply or something. They have a bunch.

 

[benb]

Can you see the value of the load resistor that's connected to that 12AX7 plate? It would probably help to know that.

Can you tell what sort of "actuator" that is? I've only seen or heard of (electro)magnetic in spring reverbs, but that looks different from any I've seen I wonder if that might be a piezo transducer. I can't tell offhand from the picture.

Here's some pages that may help, especially in choosing a replacement. Offhand I'd suggest going with the highest input and output impedances:
Spring Reverb Unit For Guitar
Spring Reverb

 

[Enzo]

The cap off the plate type reverb drive will expect the highest impedance reverb pan input there is. In the case of the standard Accutronics and similar reverb pans, you would want the second character to be an F. That second character specifies input impedance. As in 4FB2C1B.


The common Fender type reverb drive circuit uses a small transformer and will be low impedance, as in 4AB2C1B. Most common solid state drives use the second highest impedance, as in 4EB2C1B.

In every case I know other than special order or special purpose reverb pans, the output transducer is a B type, a relatively high impedance, perfect for feeding a tube grid.

The first digit specifies the pan physical size. The 4 (or also a 9) is the full size pan, I think 17" long. The much shorter pans for smaller spaces has an 8 as the first digit.

 

[pdavis68]

Thanks for the details. Would this fit the bill?

https://www.tubesandmore.com/products/P-RMOD-8FB3C1B

I've found this particular model from 3 sources and can't seem to find any other 8Fxxxxx variants. I would think I'd prefer and 8FCxxxx, but I couldn't find one.

 

[Enzo]

Ought to work.

You might prefer and FC, but in all my decades in this business I have never seen one. Almost without exception, all the reverb pans will have the B output.