Farfisa Compact Reverb Tank

[newperson]

Hi,
A bit off topic, but
can anyone explain how a Farfisa Compact spring reverb tank works?  I have read that it uses piezoelectric transducers but I can not see how the usually disc shape fits into the cartridge shape idea.  I see a small metal strip that is connected to the ground and input wires.  There is a goo inside also, but the wire fully makes a connection between the input signal wire and ground. 

Any ideas one how this works?

[Quackzed]

  i've seen piezodisk spring rvrbs that suspend the spring btween 2 piezo disks where the spring is physically connected to one side of each piezo disk, basically i'd guess that one piezo is the driver,(vibrates the spring with signal, the other i'd guess is the 'sensor' or 'pickup' and turns the spring vibration back into an ac signal... thats my guess...

[joelindsey]

I just repaired the reverb on my Farfisa Compact a couple weeks ago. It's hard to explain without photos, but I'm pretty sure the wire crosses over a gap in the plastic box and rests on a sort of "bridge", which is connected to the piezo element. If the reverb sounds weak or doesn't have a lot of sustain it could be the bridge is out of place. Pushing it around a bit till it sits in the middle worked for me. This all probably doesn't mean much without photos...

For what it's worth, I tried swapping it for a normal spring reverb tank to see if it would work. It didn't.


Here's a bad photo of mine...

[newperson]

No that is a fine image.  I was able to look inside the cartridge as it was broken.  The send unit on the left just had two thin pieces of metal sandwiched together.  Each connected to where the wire comes in with that small barrel connector.  It read close to 0 ohms, so really mostly a direct connection.  Is yours connected and reads 0 ohms in the same way?  Or does it use the right and left connections instead of the connections on top of one another?

It did work after I cleaned the connections inside the cartridge.  There was plenty of corrosion preventing the 0 ohm connection inside.  I was just wondering how the whole thing works, because I read that a piezodisk should read open.  I should have taken a few photos before gluing it back together.

Thanks for the discussion,