Reverb Tank - MOD®, 4FB3A1B, Long Decay, 2-Spring

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Reverb Tank - MOD®, 4FB3A1B, Long Decay, 2-Spring

In stock
  • Replaces: 4FB3A1B
  • Solid, sturdy construction
  • Type: Long (2 Spring) tank
  • Decay: long decay
  • Input: 1,475 Ω
  • Output: 2,250 Ω
  • Connectors: Input grounded/output grounded
  • Locking: No lock
  • Mounting: Horizontal/open side down

Compatible amps include Ampeg® amps (some models), Epiphone® EA-28RVT, Gibson® GA19RVT and GA20RVT, Music Man® RP and RD series, plus others.

The MOD® 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.

RoHS Compliant
Item ID:
Input Impedance:
Number Of Springs:
Output Impedance:
Tank Length:
Product Measurements
Connectorsinput grounded, output grounded
Decay Timelong (2.75 to 4.0 s)
Grommet Hole Diameter0.04 in.
Input Impedance1,475 Ω
Item Height1.5 in.
Item Length16.75 in.
Item Width4.25 in.
Length16.25 in.
Mounting Hole Center to Center A8.75 in.
Mounting Hole Center to Center B3.75 in.
Mounting Hole Diameter0.2 in.
Mounting Planehorizontal, open side down
Output Impedance (Zout)2.25 kΩ
Packaging Information
Packaging Dimensions17 in. × 5 in. × 3 in.
Weight (Packaging)1.75 lbs.

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Questions and Answers

Click each question to see its answers.
Asked by Anonymous on September 18th, 2016.
Matt H
September 20th, 2016
Hello, this reverb tank has a horizontal mount. I do not think it should make that much difference regarding the functionally of your amp.
Asked by Anonymous on August 5th, 2017.
Matt H
August 9th, 2017
Unfortunately this is something we do not carry.
Asked by Anonymous on December 30th, 2018.
January 8th, 2019
Staff Member
This has a different connection orientation than the tank in question. A qualified tech may be able to modify this tank to work for your amp.
Asked by Anonymous on March 24th, 2019.
March 26th, 2019
Staff Member
Yes, we ship internationally.

Product Reviews

5.00 out of 5 based on 3 reviews
- August 25th, 2019
5 out of 5

Excellent!-Big Improvement to my reverb in my MusicMan hd 130

- January 27th, 2019
5 out of 5

I was able to replace the reverb tank with a new MOD and it works perfectly. Thanks!

- October 9th, 2018
5 out of 5

I bought this MOD® 4FB3A1B reverb tank for my 1979 Music Man 112RD sixty-five. This is the early version of the 112RD with the 6CA7 vacuum tubes (valves). I replaced the original OC Type 271 reverb tank, which sounded brittle and harsh. The MOD® tank transformed the sound of the reverb and it now sounds full, rich, smooth and natural. I had to buy a new reverb bag and longer wires as the OC unit was much shorter. I thoroughly recommend this high quality, well-engineered unit.

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