Which Vibroverb?

[Cliff Schecht]

I've read about some mods to the tremolo circuit in the brown amp to get it more intense and also to guarantee that it oscillates. They were simple things like bypassing a cathode and something else. I saw these while I was troubleshooting and didn't think to write them down..

I'd like to put mine in a head really. There has to be a way to properly shield the reverb pan without getting too extravagant. I've also heard of people using some sort of humbucking configuration for the reverb pans pickups but never saw anything expanded on this.

Also the reverb pan I have now is a weak POS with really off impedances. It functions but there is no depth. I want that deep luscious Fender reverb. What pan should I be looking at? My reverb driver is a 2k:4 Ohm transformer (should be 4k:8 Ohms with an 8 Ohm load). Should I change this out for a proper 5k:8 Ohm unit?

[martin manning]

Cliff I think you want to get a Fender reverb driver trans 125A20A(B) Equivalent, 23k primary, 8 ohm secondary. For the pan 9AB2C1B, I think. AES claims their Mod units are more vintage sounding than the current Accutronics. Maybe others agree?

[Cliff Schecht]

Oh wow I didn't realize the driver transformer impedance was so high! I will definitely get a proper unit put in there.

Also thanks for the reverb pan recommendation. Once I get a bit of spare money I'll order this (yeah, I'm that broke!).

[Phazor]

Thanks for the info Martin.

I checked AES on the tanks/pans The 9AB2C1B is a 10 ohm input and 2575 ohm output with 3 springs.

The 4AB3C1B is the 8 ohm input 2250 ohm output with 2 springs like the original 1964 tank, if that's what your after.

The 3 spring should have a denser reverb with the 3 springs.

This info is in an article on the site; Spring Reverb Tanks explained and compared. its a hyper lin in the accutronics section. It has a great deal of info to sort out all the choices.

The Drive Transformer is listed As 125A20B for all Fender amps using Hammond reverb pans. This is the same number in my original Black Vibroverb.

[davesi]

After putting a medium reverb tank in a Rocket head, shielding the open side and overlapping ends where the transducers live with ultra perm helped a bit. Finding the right tube helped the most.


http://www.goldmine-elec-products.com/p ... ber=G18646


Dave