Mark III - Can you just unplug the reverb tank?

herrball · Jul 3, 2011

Hey guys

Was converting my MK III from a combo to a head this weekend and noticed why the reverb was sounding weak - one of the springs had broken off. ( inserts into each end had broken inside)
Rather than spend $30-40 on a new reverb tank, can I just unplug the grey/white cable on the amp chassis or does this then render an incomplete circuit? If its just like not having anything in the effects send, great but I know there is a circuit driving the reverb and am hoping it works like the effects send if nothing is attached.

Any advice would be greatly appreciated.

Thanks in advance guys.....

Blueracer · Jul 3, 2011

You can disconnect the reverb tank without any ill effects. The circuit that drives the reverb tank derives it signal from the preamp path, sends it through the reverb tank, then adds it back into the preamp path. So the reverb path is parallel to the preamp path not inline with it. Rather than disconnect the tank I would suggest just turning the reverb control all the way down. It does the same thing effectively, i.e. disconnects the reverb loop. Disconnecting wires will leave them dangling inside the amp. Not a good thing in my opinion. Hope this helps.

herrball · Jul 3, 2011

That's a simple solution ...I'll go with it.

Thanks

&gt;Photi G&lt; · Jul 4, 2011

yea, but don't forget that there is an output transformer driving the reverb. You may cook this, especially on a mark III, which has a reverb transformer notorious for burning up unexpectedly. Proceed with caution my friend.

Blueracer · Jul 5, 2011

>Photi G< said:
yea, but don't forget that there is an output transformer driving the reverb. You may cook this, especially on a mark III, which has a reverb transformer notorious for burning up unexpectedly. Proceed with caution my friend.

Another good reason to leave the reverb tank connected and turn the control off. Disconnecting the reverb tank will leave the transformer unterminated. It is like not connecting a speaker to the output. It will produce a mismatch and could compromise the transformer. I have had Fender amps without a reverb tank that tolerated this. It doesn't mean that this would extend to Mesa amps or that it is particularly good for Fenders for that matter. Good catch Photi G.

chipaudette · Jul 5, 2011

On my fender deluxe reverb reissue (all tube, with a reverb circuit similar to the boogies), I've run it without a reverb tank plugged in and actually had some arc'ing within the amp chassis. Like the previous posts said, don't run it without some sort of connection. You're just asking for trouble.

The recommendation to just turn the reverb to zero is the easiest and most sensible.

Replacing the reverb tank is also inexpensive and easy.

Chip