[sdiy] How do reverb tanks work?

[RMC]

>I just learned a few days ago, that the Reverb of Farfisa Compact Organs 
>was
> built from two phono cartridges (one as a driver, one as pickup, with a 
> spring in
> between.)

> think that means they are "ceramic" cartridges, which I believe is
> another way of saying "piezo elements". For whatever that's worth

> A cutting head and a phono cartridge might work better. How much current 
> can
> be run through a phono cartridge before meltdown? Hmm....maybe a
> piezo-cartridge

Going back 25 years to when I was a nipper and didn't know much (still 
don't), I got hold of an electric fire. I removed the Nichrome heating 
element from it which was basically a giant spring, about half-an-inch in 
diameter.

I then got a metal plate (6" x 3") and Araldited six piezo-electric speaker 
elements to it, wired them all up in series/parallel and drove them from my 
50W RMS audio PA.

I attached one end of my giant spring to the centre of the plate and then 
stretched it across my bedroom, similarly mounting the other end and gluing 
the dynamic mic cartridge from an electrovoice mic to the plate. both ends 
were mounted on the backs of chairs, about 8 feet apart.  The spring drooped 
alarmingly in the middle but cleared the floor.

my MS-10 sounded brilliant! Eventually, the PZ drivers burnt out but it was 
a fun experiment.  Luckily, my synthi AKS tank is somewhat easier to fiddle 
with.

Cheers

RMC, England