[sdiy] How do reverb tanks work?

[RMC]

Ray

>  on the other end another magnetic ferrous bead wiggles and induces a 
> voltage into the "pickup" or output coil (generally higher impedance) than 
> the other coil.

OK thanks , that's confirmed my thoughts;  it's good to know.  In which 
case, higher flux magnets should generate larger outputs and hence better 
SNR.  Some of the NIB magnets would be interesting to get in tiny sizes... 
fitting might be tricky but not impossible.  I would need to check the mass 
of the replacement if I wanted to experiment that much (which I don't - just 
thinking out loud!).

> The coils are wound with the teeniest wire in the world and fixing them is 
> next to impossible. Notice I say... "next to" because with enough 
> patience, care, light and magnification I suppose one could reconnect the 
> coil wires to the input/output terminals and the thing would be as good as 
> new.

You suppose correctly - it is possible. I used my stereo zoom microscope to 
do the remedial work on the coil:

http://www.excaliburmineral.com/scopes/mb10basic.jpg

It took a couple of hours. The results seem fine!  I was careful to realign 
those tiny spring magnets on the output end with the gap in the core. White 
noise at the input seems to have about the same bandwidth at the output so 
that's a good enough test for me at the moment!

Cheers

RMC, England