Vox AC15C1 Reverb Not Working Then Working

Written by stringbox

[UPDATE]
I speculated moisture could have been a culprit in causing the reverb not to reverberate. It may just be a bad reverb tank that I should replace. Honestly, I just don’t know. If I rock the amp back and forth (probably not the best idea) sometimes the springs will bounce, some electrons will start to flow correctly and the reverb will start working. Go figure. I should upgrade the reverb tank. Or get a local store to do it and possibly upgrade the tubes as well.

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Just a bit of a first world problem…recently, twice now, the reverb has ‘gone out’ on my very awesome Vox AC15C1 (seriously it’s an awesome amp), but I do have a theory as to what may be happening, because it does start working again. My theory is very amateur, mind you, as I am not too well versed in electronics and in this case, reverb tanks. I like that the gizmo that makes the reverb is called a reverb tank. (I’m easy.)

So my theory is that the culprit is probably moisture and/or cold, or probably just moisture. Here’s the scenario. I’ve started playing guitar for church, because they found out I play guitar and asked me too, and it’s been good for me anyway, and back to the amp… I’ll get it to the theater (we have church in a movie theater) and I’ll set it on an amp stand, warm the tubes, fire it up and no reverb. Turn it off and on, no reverb. Unplug, plug the footswitch I got to on/off the reverb and tremolo, still no reverb. The 2nd time that this has happened, when I got it home and fired it up, I could hear a faint, low buzz/hum which I noticed was stronger when I turned the reverb up. And still there was no reverb but for maybe a very, very faint hint.

Days later when playing on the amp, it has reverb and sounds perfectly fine. So what’s up? I’m guessing moisture, because it was raining and cold this last time that it happened. I don’t recall the weather the first time this occurred. And I did cover the amp in a garbage this to keep it from getting wet, but the humidity here is usually pretty strong in general so I’m hoping my theory has some merit. From now on I’ll try to pay attention to the weather conditions if/when the reverb goes out again.

Also, I’m writing this so if anyone else experiences such a phenomenon they can confirm and/or just feel better that their amp is still ok. And that reverb tank I mentioned… it really is a metal box inside the amp with about four long thin springs (8 inches or so?) which are themselves suspended in said box by tiny springs. Just interwebz searchify “reverb tank” for many pictures. Spring reverb, in this case is pretty neat. It’s literally created by springs. Yay, springs!

Lastly, please, please, please do not go messing around the inside of a guitar tube amp without good knowledge of what you are doing. A high voltage charge can remain in the capacitors in the amp and it’s extremely dangerous. There, that’s said. Seriously though, it is dangerous. But, yay springs!