Reverb tank for RD100 mystery solved?

spangler41

I recently received a MM RD100 head with good working reverb. I pulled the tank to get the number. It is an
Accutronics short (9-1/4") 3-spring tank 8FB2A1B
with
1925 Ohms input
2575 Ohms output
Both input and output jacks are grounded.

This tank is available from https://amprepairparts.com/reverb.htm#8.

There are other compatible tanks that have the input NOT grounded but the output grounded. This would require simply running a wire across from the ground of the input to the ground of the output. Those are:

8FB2C1B
8FB3C1B

The MOD tanks are available in those configurations and are sold by Antique Electronics, Amazon, eBay, CE Distribution, etc.

Hope this helps.

Full Name
Bill Moore

Member for

10 years 9 months
Profile picture for user bill_moore

bill_moore Mon, 10/15/2018 - 13:11

I changed the tank in my RD One Hundred to the "4" series, and really like it, much fuller reverb!

Full Name
Lars Verholt
Music Man Equipment
HD-130 head, 210X cab, 210RH cab, RD-50 110 combo, Sixty-Five 112 combo, RP65-112

Member for

10 years 9 months

lmv Mon, 10/15/2018 - 15:25

Bill, you did what I've been contemplating a few times. The RD/RP series amps have the smaller tanks in them and they are not nearly as nice sounding as the long tanks found in the larger amps. If you were into surf (or just like heavier reverb) one could try a type 9 tank - that would give you even more.

Cheers,
Lars

Full Name
Bill Moore

Member for

10 years 9 months
Profile picture for user bill_moore

bill_moore Mon, 10/15/2018 - 15:53

Lars, several years ago, I built a "Twin" clone, and did a "shootout" with reverb tanks. I had an old Gibbs from the 60's, a current production,(then), "4" series Accutronics, a "4" series Belton, a "4" series Mod, and a "9" series Accutronics. I had two country players and myself listening while we A/B'd them all. The consensus was the Mod sounded best! I had thought the Gibbs would be the most desirable!
I would have to look, but I seem to recall that the original RD tank had the rounded corners, like the ones made by "beautiful Wisconsin girls", O.C. Electronics. I do think it had an Accutronics number though.

Full Name
Ewan Milne Tytler
Music Man Equipment
Music Man 110RD fifty
Music Man 112RD sixty-five
Two OLP MM4 Silhouettes with Lace Sensors

Member for

6 years 9 months

Emtytler Fri, 10/19/2018 - 04:42

I have recently replaced the reverb tank in my 1979 112RD sixty five. It came with the factory OC type 271 which sounded harsh and brittle. This is a short tank with rounded corners. I replaced it with a MOD 4FB3A1B tank. The sound was completely transformed. It now sounds rich, full and natural. It is relatively subtle, not “bathroomy” like some Fender reverb circuits. I would recommend trying this $19 tank in a RD65 or RD100.