Reverb Tank - Mod® 9AB3C1B, Long Decay, 3-Spring

Mod Electronics
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Reverb Tank - Mod® 9AB3C1B, Long Decay, 3-Spring

In Stock
  • Replaces: 9AB3C1B
  • Solid, sturdy construction
  • Type: Long (3 Spring) tank
  • Decay: long decay
  • Input: 10 Ω
  • Output: 2,575 Ω
  • Connectors: Input insulated/output grounded
  • Locking: No lock
  • Mounting: Horizontal/open side down

Compatible amps include select Fender®, Hughes & Kettner, Marshall™, Ampeg, Crate, Mesa Boogie, Guytron, Rocktron, DOD, Summit Audio, and Smokey amp models, plus others.

The Mod Electronics Reverb Tanks are high quality upgrade units. Some of the major differences between the Mod®s and other reverb tanks are that the Transducers are wired directly to their respective RCA jacks as opposed to current production tanks where Transducers are connected by a detachable plug to their respective RCA jacks. This makes the tanks less receptive to any outside interference. The original Hammond Accutronics tanks from the 1960s were also wired directly to their respective RCA jacks. In addition, very close attention has been paid to the spacing and size of the lamination of the Transducers resulting in a more vintage like tone.

Questions about reverb tanks? See our tech articles for more information.

Item ID:
Input Impedance:
Number Of Springs:
Output Impedance:
Tank Length:
RoHS Compliant
Product Measurements by Type
Connectorsinput insulated, output grounded
Decay Timelong (2.75 to 4.0 s)
Grommet Hole Diameter0.2 in.
Input Impedance10 Ω
Item Height1.5 in.
Item Length16.75 in.
Item Width4.25 in.
Mounting Hole Center to Center A8.75 in.
Mounting Hole Center to Center B3.75 in.
Mounting Planehorizontal, open side down
Output Impedance (Zout)2.575 kΩ
Thickness0.04 in.
Packaging Information
Packaging Dimensions17 in. × 5 in. × 3 in.
Weight (Packaging)1.75 lbs.

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Specifications, Files, and Documents

Sound Samples:

Questions and Answers

Click each question to see its answers.
Asked by Anonymous on January 31st, 2018.
Matt H
February 2nd, 2018
Typically the Vox AC30's take a 9EB2C1B.
April 20th, 2018
Yes, it will. It has a longer decay than the 9EB2C1B.
Asked by Anonymous on March 17th, 2017.
Matt H
March 17th, 2017
If you are referring to the mounting plane then we would not have a 9AB3C1C.
Asked by Anonymous on March 22nd, 2017.
Matt H
March 22nd, 2017
The mounting plane for this tank would be horizontal open side down.
Asked by Anonymous on November 30th, 2017.
Matt H
November 30th, 2017
The tank in this kit is a 9AB3C1B and is a long tank (16.75").
Asked by Anonymous on February 1st, 2018.
Matt H
February 2nd, 2018
The 4AB3C1B and 9AB3C1B are compatible with each other.
Asked by Anonymous on April 5th, 2018.
April 6th, 2018
Staff Member
The Input and Output impedance must match in order to be an acceptable replacement.
Asked by Anonymous on August 17th, 2018.
August 17th, 2018
Staff Member
We wouldn't advise using a tank that has different insulation points and input and output impedances. We do carry a 8AB2A1B in both the MOD and Accutronics brand that you can view here: MOD Tank Accutronics Tank:
Asked by Anonymous on December 11th, 2018.
December 11th, 2018
Staff Member
This appears to be a different tank than the one in question. The most important specs that are required are the input and output impedance. If your amp has a 10 Ohm input and a 2,575 ohm output impedance, this should work for your amp.
Asked by Anonymous on August 17th, 2019.
August 21st, 2019
Staff Member
There is a schematic online that shows a Hammond IV C. If this is the same as a Gibbs type C, the Accutronics code is 4FB3D1B. Please check the schematic along with your amplifier to confirm.
Asked by Anonymous on January 26th, 2020.
January 27th, 2020
Staff Member
It would physically fit, but the 4BB3C1B and the 4EB3C1B are the designated tanks for the Blues Deluxe and the Blues Deluxe reissue respectively.
Asked by Anonymous on April 14th, 2020.
April 14th, 2020
Staff Member
The difference in impedance ratings between the two tanks is close enough to use without concern of damaging the unit in any way.
Asked by Anonymous on June 18th, 2021.
June 18th, 2021
Staff Member
Absolutely. The character in question only refers to the decay length, 2 being medium while 3 indicates a long decay, so the 9AB3C1B will be the exact same specs as the tank currently in your amp, but will provide a longer decay rate.
Asked by Anonymous on June 30th, 2021.
June 30th, 2021
Staff Member
This is an appropriate replacement for a 4AB3C1B tank, that is used in Fender amplifiers from that era, so this should work. You will want to verify that your amp currently uses a 4AB3C1B tank, and if it does, this will certainly work as a replacement.
Asked by batflash on October 18th, 2022.
October 18th, 2022
Staff Member
It is intended to be mounted with the open side down, but it would still likely work if installed with the open side up. The reverb effect may suffer slightly.

Product Reviews

5.00 out of 5 based on 3 reviews
Fred Norman - March 11th, 2020
5 out of 5

The MOD long decay, 3-spring made a big difference in the quality of my sound. My tech friend, Paul, and I have been restoring / renovating a mid-60s Benson 300 tube amp. Paul had to replace the original reverb transformer ( it was an Audio Interstage Transformer with very high impedance ) with an 8-Ohm Fender transformer in order to give me more options in different reverb tanks. I also tried the MOD long-decay, 2-spring model but I was buried in reverb that wasn't very usable, in my opinion. The 3-spring model really cleaned-up the overall sound and had much more clarity. I'm also going to compare it with the MOD medium-decay, 3-spring model which is currently on order. Great quality MODs!

Warren Paul - February 1st, 2019
5 out of 5

I've had a Limited edition (12 inch alnico speaker) '65 Princeton Reverb re-issue for about a year, and, though I really love the tone of the amp, I never wanted to add any more than a tiny bit of reverb because the factory unit had an irritating flutter. I replaced the original 2-spring short decay tank with this 3-spring long decay unit and the improvement was dramatic - a smoother, fuller sound. The swap was easy, but I did notice that the color code on the input and output connectors was different from the original, so make sure you connect your new tank using the in and out labels as your guide. Thank you, Amplified Parts, for having such an informative web site.

Anonymous - September 15th, 2011
5 out of 5

Good sound. better than Accutronics.
I attached it. tube spring reverb(guyatone FR-3000V)