# Ideas to improve Garnet “cathedral” reverb



## Krfrieh (Apr 11, 2020)

I’m just not thrilled with the reverb in my Revolution I. It has the original O.C. folded line tank mounted vertically. From what I have read, the input and output impedances are 8 ohm and 3k ohm respectively. With that in mind, what replacement tanks might be an option to improve the sound, or are there other modifications to the circuit that can make the reverb less “cathedrally”?


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## Paul Running (Apr 12, 2020)

Krfrieh said:


> less “cathedrally”


As in a less-reflected sound effect: it may be simulated by less treble plus a reduced decay time. You can select pans with different decay times. If you know the brand and model of your tank, you should be able to confirm the decay time by the spec sheet.


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## Krfrieh (Apr 11, 2020)

O.C. Electronics is long gone. I’ve not been able to locate any specs sheets on their reverb tanks.


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## Krfrieh (Apr 11, 2020)




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## Paul Running (Apr 12, 2020)

What's the type number for the tank?


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## ga20t (Jul 22, 2010)

Older mushroom knob Rev I, or later model with knob brites and mid control?


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## Hammerhands (Dec 19, 2016)

You might try getting a hold of Larry Kohut at Red Rock Amps, he has seen a lot of Garnets and may know how Gar later modded those amps. Or maybe Randy Jamz.

Gar did improve the reverb on one amp I used to own, and told me that he could improve the reverb on another.


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## Paul Running (Apr 12, 2020)

Steve Kimock has an article on decay time of reverb tanks:
"The decay time is usually defined as the time it takes a sound to decrease by 60 db.* Decay time is determined by the acoustical properties of the reflective surfaces. _What controls Decay_? The DECAY TIME performance specification of a reverb unit is dependent on the choice of material type and thickness of the DAMPER DISC. This is a customizable option when ordering an Accutronics tank, so it will be a variable when choosing which Reverb unit is right for you. When ordering a tank, one follows this guide when selecting the correct decay time":

DIGIT #4 - DECAY TIME
1 = Short (1.2 to 2.0 sec)
2 = Medium (1.75 to 3.0 sec)
3 = Long (2.75 to 4.0 sec)"


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## Krfrieh (Apr 11, 2020)

ga20t said:


> Older mushroom knob Rev I, or later model with knob brites and mid control?


it is a later model Rev I, with pull bright on the volume on the far left and pull boost on the master volume on the far right.


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## mrmatt1972 (Apr 3, 2008)

I’ll just play devils advocate here and suggest that there are so many really great sounding reverb pedals out there now that you’re probably better off buying one of them. I was never a fan of the Garnet reverb.


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## Jerome (Dec 4, 2015)

You could try a Mod reverb pan , the one that is speced for a Fender Twin Reverb . The input and output impedances should match up . Half a 12au7 will not drive the pan as hard as a 12at7 , like Fender uses , but the result may be acceptable to you . 
If you want more drive , the rev drive tube could be replaced with a 6FQ7 , though this will require rewiring the tube socket , and perhaps tweaking the associated resistors and capacitors . Then again , you may need more signal going to the rev drive tube to take advantage of the 6FQ7 .


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## Jerome (Dec 4, 2015)

Spring Reverb Tanks Explained and Compared | Amplified Parts







www.amplifiedparts.com





Some great info .


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## Krfrieh (Apr 11, 2020)

Paul Running said:


> What's the type number for the tank?


Sorry for the delay in my reply. The tank number type is 72. What does that tell you? Please advise.


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## Krfrieh (Apr 11, 2020)

I just installed a $30 Mod tank 8AB2A1B. Sounds much better than the original OC tank.


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