Reverb Tank - Mod® 4FB3A1B, Long Decay, 2-Spring
- 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 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.
Connectors | input grounded, output grounded | ||
Decay Time | long (2.75 to 4.0 s) | ||
Grommet Hole Diameter | 0.04 in. | ||
Input Impedance | 1,475 Ω | ||
Item Height | 1.5 in. | ||
Item Length | 16.75 in. | ||
Item Width | 4.25 in. | ||
Mounting Hole Center to Center A | 8.75 in. | ||
Mounting Hole Center to Center B | 3.75 in. | ||
Mounting Hole Diameter | 0.2 in. | ||
Mounting Plane | horizontal, open side down | ||
Output Impedance (Zout) | 2.25 kΩ | ||
Springs | 2 |
Packaging Dimensions | 17 in. × 5 in. × 3 in. | ||
Weight (Packaging) | 1.3007 lbs. |
![]() | All Models |
![]() | All Models |
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![]() | All Models |
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Product Reviews
Reverb tank arrived well packaged. Now installed in a 1970 Traynor YGM III, great improvement.
Excellent!-Big Improvement to my reverb in my MusicMan hd 130
I was able to replace the reverb tank with a new MOD and it works perfectly. Thanks!
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.