Ampeg V4 Reverb tank removal.. a weird request

[Steelwitch]

Hey folks, a client brought me a 70’s ampeg V4 with a laundry list of issues which have all been taken care of. He would like the Reverb tank removed since he does not use it.. I tried to convince him to keep it in there but he really wants this..

I need to replace the tank with some kind of load, correct? I’m not positive of the exact impedance of the tank but wondering if anyone else has done this or has tips? Thank you!

[Enzo]

Unplug it and move on with your life. The pan is driven off a tube plate via a cap, forget impedances and loads.

[g1]

^^^ What he said.
It's a high impedance tank and the driver tube will still be loaded by it's plate resistor.
You can permanently engage or hardwire the footswitch jack so the return circuit doesn't add any noise, but that would only happen if the reverb pot was turned up.
Some might suggest removing the driver tube but I would not want to risk any increase in the already very high B+ in these amps.

[SoulFetish]

maybe this goes without saying, but I would remove the RCA cables from inside the chassis. Or, tie them off so that there is no risk of the plugs contacting any other part of the circuit. The reverb input is capacitively couple (as mentioned above), but when unloaded, the capacitor charges to a high voltage and the RCA plug can give someone a bit of a shock. So, if you were inclined, you could put a shorting cap on the plug, or solder an 82k resistor in parallel with the reverb input side of the capacitor. This really has no effect on the reverb performance, so you can just leave the resistor in circuit if the customer decides they want reverb again.

[nsubulysses]

I removed the tank in my V4 many years ago

I wrapped the reverb RCA plugs in a plastic bag held on with twist ties so they can flop around to their hearts desire without causing a shorting problem.

[Steelwitch]

Thanks everyone!

[J M Fahey]

There was a famous Russian Orthodox sect, the Skoptsy, who swore eternal celibacy, so no reproduction or kids in their life, so they castrated men and practiced mastectomy on women because they had no use for those parts anyway.
https://en.wikipedia.org/wiki/Skoptsy
Maybe they also avoided a lot of noise in their life

Not just "a couple crazy guys" , they reached a peak of 100000 members in the early 20th Century.

Oooops, maybe "members" is what was actually missing there

Back to Electronics, I guess shorting the return jack (and leaving Reverb there) will actually be more silent than plain removing the tank.
Just sayin'

[TimmyP1955]

Have some fun and experiment: With some amps, if you connect the reverb send and return, the reverb circuit makes a fun parallel hi-gain stage.

[Justin Thomas]

Just put a 470k in place of the tank & screw around from there! Noisy as crap, though... But fun anyway. If it's punk rawk, who cares?

Jusrin

[J M Fahey]

Yes, in the early 70´s a guy made and sold a device called "the ice cube", literally a couple parallel RCA plugs, probably including a 10 ohm resistor not to blow the reverb drive transformer, encapsulated in black resin.
And his mold was literally a rubber ice cube tray so he could pull it out afterwards.
RCA plugs were the proper distance so as to straight plug into Reverb send-return jacks.

Imagine!!! A FENDER!!! (and a Blackface at that) with *footswitchable DISTORTION!!!!*

Take that, Marshall!!!

Maybe they also included a couple clipping diodes, at least to avoid blowing next triode grid with a speaker level signal.

[SoulFetish]

Yes, in the early 70´s a guy made and sold a device called "the ice cube", literally a couple parallel RCA plugs, probably including a 10 ohm resistor not to blow the reverb drive transformer, encapsulated in black resin.
And his mold was literally a rubber ice cube tray so he could pull it out afterwards.
RCA plugs were the proper distance so as to straight plug into Reverb send-return jacks.

Imagine!!! A FENDER!!! (and a Blackface at that) with *footswitchable DISTORTION!!!!*

Take that, Marshall!!!

Maybe they also included a couple clipping diodes, at least to avoid blowing next triode grid with a speaker level signal.

Not a bad idea. I suppose with an appropriate load on the secondary to take some of the heat, you could also tap signal off the resistor and connect an audio Transformer in parallel to step the voltage up enough to overdrive the next stage. You might be able to still keep the secondary impedance low enough to push the grid a bit into the +V region and get another
flavor of overdrive. These audio Transformers are cheap and small. (and assumes a fender Transformer coupled reverb driver like mentioned above)

[drewl]

You have to pad the signal down, otherwise it's too hot.

I experimented with this on a Marshall 2210 I had.

Eventually what I did was leave the reverb in but increased the gain of the return amp so it was like a solo boost with a bit of reverb
thus making it a three channel amp!

Did it to the 1x12 combo version 4210 I had also.