What is a reverb tank?

Technically, a reverb tank is an electronic apparatus that modifies the input signal to add reverberation to the output sound of an amplifier.  In my case it was a fault that caused the loss of a sale of said amplifier.  It was also the bit that clinched the deal later on.

I began advertising to sell the amp a few months ago; a beautiful oak cabinet, one-hundred watts of tube-driven power, a warm and natural sounding amp.  What I did not realize, simply due to lack of use, that the reverb effect had stopped working.

Finally, a buyer stepped forward, came to my home with guitar in hand, and plugged in.  I could tell he was quickly falling in love with the sound, and it does sound sweet.  Over-driving the tubes gave a growl that would make ZZ-Top smile, and the clean channel was crisp and clear.  The flanger sounded good too.  Then came the reverb...knob twisting, connector jiggling, footswitch clicking ensued; nothing.

The fellow looked visibly disappointed as he left, on his way to try another amp.  He bought the other amplifier and later wrote to me expressing regret over his purchase.  He still wanted my amp, but understandably for less money because of the missing reverb effect.  That is when I decided to take a leap of faith.

The next day I laid the amp on its side, took off the back cover, then carefully removed the head where the electronics are housed.  So far so good, things are going along without incident.  Six screws later and the top of the head was inverted to expose what I came to learn was the reverb tank.

Even though I build and repair computers, I felt like this might be over my head, until I examined the tank.  On one end was an RCA style plug, with a cable to the circuit board, connected at both ends.  There was a second similar cable laying on the circuit board, one end connected to the board.  The other male end was laying loose on top of the components.  Of course, the other end of the reverb tank had a second RCA female socket, empty.

With the connection restored, six screws secured the enclosure, and the head was returned to its place inside the cabinet.  The back cover was replaced and the amp powered up.  After a few minutes of waiting for it to warm up, the pleasure of owning a tube amp, a click of the footswitch produced a new sound not heard for a very long time.  Running the volume all the way up and rotating the reverb knob also made new sounds.  Reverb was back!

Emails flew back and forth, the first letting the buyer know that reverb had indeed been restored, the last word from him was he will sell the amp he bought in lieu of mine and will buy mine when he has the funds together to pay the full asking price.

What's the point of this tale?  It reminded me of things that the isolation and darkness of unemployment suppress; the motivation and ability to take a risk, to think out of the box, and step out of one's comfort zone to make something better.