Need help choosing reverb tank for amp bought with tank missing (schematic included)

[TexasJoel]

Hello all. I recently bought an early-90's Carvin XT112, which is a 1X12 combo with a pair of EL34s. This is the combo version of the otherwise identical Carvin X50b head.

I bought it for cheap locally, mostly because it had an aftermarket JBL K120 speaker installed, and I was hunting for one of those. But I have also heard good things about the clean channel on this and other Carvins of similar vintage. I will agree - good clean channel.

But it was missing the reverb tank when I bought it. I would like to buy a replacement tank, to get the reverb running on this amp.

Visits to the Carvin website, standard google searches, review of available schematics have not turned up any answers about what the stock tank was on this model.

Can anyone advise on what tank I should use?

I'm attempting to attach a schematic, with a markup to draw attention to the reverb circuit:
X-Series Amp Schematic - reverb notes.pdf

The schematic will show two halves of a 4558 op-amp running in parallel to drive the input of the reverb tank, and a single 4558 op-amp receiving the signal return from the tank.

While I can figure out basics like that, I don't know enough about ballparking impedance etc. to figure out what I should be looking for in terms of reverb tank specs that would be a good match for this circuit.

I'm thinking I probably want a long tank with 3+ springs, but I don't know about other specs (like input/output impedance).

Can anyone offer recommendations? Or maybe (just maybe?) some kind soul has a Carvin XT112 (or X50b) and is willing to tell me the codes stamped on the reverb tank?

If it helps at all for this discussion, here is a vendor selling a variety of tanks:
https://www.amplifiedparts.com/products/reverb_tanks

Many thanks for your time!

[The Dude]

Why not just call Carvin and get it directly from them?

[nevetslab]

You'll need high input impedance. There's a 9FB2A1C Mod tank on pg pg 3 of Amplified Parts...the website you gave. 1475 ohms input imped, 2575 output imped.
But, the mounting configuration is mounting on a wall surface, length horizontal, connectors up. If you need it to be open side down, horizontal, mounting on the floor of the cabinet, this isn't it. For a horizontal tank, open side face down, there's a 8#B2C1B, which is 800 ohms input imped, 2575 ohms output imped., suitable for floor mounting below the speaker. a pair of 4558 IC's should be able to drive this as well. It's on page 1 on the same website. Both at or less than $20 less shpg. You'll also find the vinyl isolation pouches on this list, and probably reverb RCA cables as well.

[Mick Bailey]

The tank must be a floating input type for the Carvin. That is, the input does not connect to ground. The output coil is grounded. A Fender Hotrod Deluxe spec tank should work fine in this circuit. The dual opamp driver will power a medium impedance tank and you could go down to 310 ohm input impedance.

[TexasJoel]

Thanks everyone for your suggestions - this is really helpful.

Carvin no longer carries reverb tanks, so I can't go to them. Also, they are currently in-progress with closing their audio reinforcement line, including their guitar amp lines.

I will probably buy a few of the suggested options, and try them out to see which one(s) I like. At ~$20 each, it's worth it to me to just check out a few.

Thanks again.