MOD® Reverb Tanks

Hey Kenny. You might want to double check with Carr but I think they use a 4AB3C1B in that amp. A 4AB3A1B should work in the Mesa and be closer to that Carr tank. Keep in mind that the circuits around the tanks might have a different sound too.

We have a 9AB2A1B that can be purchased here: https://www.amplifiedparts.com/products/reverb-tank-mod-9ab2a1b

We don't have one that will fit inside as a replacement but have seen people modify their amps to connect to an 8EB2C1B.

We don't have an exact equivalent to that tank which would be a 4BB2C1A. One we have that will work is the 4BB3C1B. There are two differences in this tank. The first is that it has a long reverb decay whereas your original tank has a medium. The other is that this tank is meant to be mounted with the open side facing down whereas your original tank is meant to be mounted with the open side facing up. Send us an email at info@modkitsdiy.com if you have any questions!

A spring tank needs additional circuitry to function in an amplifier. You might want to look into stand alone spring reverb unit or pedal.

There isn't a lot of info around on that model. It might be worth reaching out to the manufacturer to see if they could provide the tank code.

The highest input impedance we have is F. We don't have a compatible tank for the 9GB2C1B.

We have a three spring 8EB2C1B which is compatible with the tank you listed. We also carry a 8EB3C1B which is the same thing but with a long decay and the 8EB1C1B which has a short decay.

Check out this video comparison! https://youtu.be/ZNHZEQRDOOI

That amp uses a 4EB3C1B.

The schematic lists a tank with a 1k4 input impedance and a 4k output impedance. We do not have a take that matches these. The closest tank we carry is the 8FB3C1B but we have no way to verify that this tank will work in the amp.

From the schematic floating around online, this amp has a reverb driver transformer with an 8 ohm secondary. I'm not sure if it will definitely work but the first tank I would try is the 4AB3C1B. This is the standard tank used in Fender amps which as also use reverb driver transformer with an 8 ohm secondary. It's also the same tank in their stand alone reverb unit which is what Dick Dale used.

Your best bet for a small power supply is going to be a solid state circuit. The smallest tanks we sell are 9.25" length x 3.375" width x 1.313" height. These come in a variety of different impedances and grounding schemes.

The 9EB2C1B will work in place of an 8EB2C1B. I would suggest making sure there is enough room to fit the larger tank. The differences can be hard to describe but a lot of people think that the full sized tanks sound bigger and airier than the small sized tanks. You can also pick a tank with a different decay time to alter the sound. 8EB2C1B and 9EB2C1B will have a medium decay length whereas the 9EB3C1B will have a long decay length.

We don't have any kits or instructions for adding spring reverb to an amplifier without a reverb circuit. This type of modification is unique to each amplifier, can require quite a bit of custom circuitry and often would require a new power transformer or the use of multiple power transformers. A stand alone spring reverb unit or a spring reverb pedal is a much easier/cheaper solution to get reverb with an amp.

DC resistance is unfortunately not much to go off since it can vary so much from the impedance. If you have model numbers I can look to see if there is any information on these amps and their reverbs.

It might not harm the amp but it will not work correctly.

We don't have anything compatible with that one. It's a pretty uncommon tank code. You might want to reach out to the manufacturer of the amp to see if they could supply one for one.

I think you might like the sound of Mod tanks given your description. Check out this video comparing 4AB3C1B reverb tanks from different manufacturers to get an idea of the tonal differences: https://youtu.be/c1IIiv89Qoc They're using the 4AB3C1B which is the stock tank in a Princeton Reverb like an Accutronics in your amp. I think you might also be interested in the 3 spring version which is a 9AB3C1B. This video compares the three spring with the two spring: https://youtu.be/Wg8hBVHEAqo

There isn't a lot of info on this amp available. It might be worth contacting the manufacturer. I know Peavey used the 8EB2C1B a lot but that is only a guess and a confirmed answer from them would be preferable.

A search online shows the 8DB2C1D as a compatible tank for that amp. I would still recommend checking the old tank for any markings to be sure since a schematic is not readily available to confirm this.

The schematic found online lists an input impedance of 1475 and an output impedance of 2250 so the FB tanks will be the compatible ones. It also looks like the input needs to be insulated and the output is grounded. The 8FB3C1B looks like it should be compatible as long as the schematic is accurate. If it has room for a longer tank the 4FB3D1B might work but the output jack might need to be modified to be grounded on this tank. This would require jumpering two solder pads on the output jack inside of the tank.

The AC15C1 uses an 8EB2C1B.

There is not much out there on this one, not even a proper schematic. Are there any marking on the original tank?

The schematic lists the 4AB3C1B as the tank used in the T50C.

Is there a letter after the 2 on your code ie 9AB2_1B?

There isn't much to go off on this one. I would guess that it is not going to be an AB type since these are more common to transformer driven circuits. BB, DB, EB, or FB would be more likely. Solid state circuits often use a higher impedance input. Looking at a schematic on the GX amps, the input probably needs to be insulated and the output sleeve is likely grounded.

Thanks MichaelT, I'll carry on with my research if i get it working i'll come back and update. Have fun during the holidays.

I don't have any way to verify this but there is a guy on Youtube with one of these. He put a full sized 9AB3C1B in his but mentioned the original was a short tank. The short version of this would be the 8AB3C1B.

The service manual says the stock tank is an 8EB2C1B. I always recommend double checking these against the one in your amp in case there have been any changes. The 8EB2C1B is a short 3-spring medium-decay tank. For the same specs but with a long decay you could use the 8EB3C1B. I'm not sure if there is room in that amp for a full sized tank but if there is, the 4EB3C1B would be a good choice. This is a 16.75" 2-spring long-decay tank that can work in place of the 8EB2C1B. Be sure to check the dimensions inside your amp though!

Reverb tanks need specific circuitry to function in an amplifier. Without modding the amp or using external equipment, a reverb tank will not function with that amp.

There is a schematic online that lists the following models: L5 Model 308A, L7 Model 309A, L9 Model 312A, and the L11 Model 313A. You might want to check yours against this schematic to make sure it is the same L11. This schematic lists the tank's input impedance as 8 ohms and the output as 2250 ohms. The 4AB3C1B might be a compatible tank. We have no way to verify it but if you have a Fender amp or a friend with one, many of them use the 4AB3C1B so you might be able to test it out.

Unless the amp already has the drive and recovery circuits needed, a spring reverb tank is not compatible without heavy modifications.

The 4FB2D1B is compatible with the Type C tanks that were commonly used in the tube driven Ampeg reverb circuits. The version we carry has the long decay and is the 4FB3D1B.

The schematic from 2009 for the Supersonic 60 shows a 4AB3C1B tank.

The stock tank is a 4EB2C1B. If you would like a compatible tank with a longer decay time, the 4EB3C1B would work. The 9EB2C1B is the three spring version of the stock tank. We also have the three spring version with the long decay time which is the 9EB3C1B. Check out the videos linked below for some sound comparisons of the variations listed here. Decay length comparison: https://www.youtube.com/watch?v=ZNHZEQRDOOI 2 vs 3 spring: https://www.youtube.com/watch?v=Wg8hBVHEAqo

A 9AB3C1B will likely work in its place but I would suggest testing before fully installing to be sure.

You should be good to install it flush to the bottom of the cabinet. There shouldn't be any noticeable difference in the sound or functionality with it tilted back.

We don't have a tank that is compatible without potential modifications to the grounding scheme. You might have better luck finding an 8AB3C1B. That tank only differs in that the decay length and won't require any modifications for use.

That one does not have the outside chassis like most tanks so I'm not sure if anyone will be selling them as a retail product. You might be able to use a tank with similar impedances to replace it. Some people modify that amp for RCA jacks to use common tanks. Another way would be to modify the tank by removing it from the chassis and rewiring it so it can mount internally.

The schematic for that amp shows part number 064063 which is the 4AB3C1B.

The stock tank in a Twin Reverb is the 4AB3C1B. A three spring version of that tank with a medium decay would be a 9AB2C1B.

It's not listed in the schematic so I don't have any way to confirm this but a few posts online point to the 4DB3C1D.

The schematic for that amp does not list any impedances or tank code. If you can locate a schematic for the older unit that you know the tank code for, you could compare the circuits. Amp manufacturers often use the same reverb circuits in different amps.

It probably won't harm the amp but it is very unlikely to produce any usable effect. We would recommend using a tank with the correct impedances.

The 8EB2C1B is the tank used in the Blues Junior.