Back on topic, if the spring driver uses a constant current source, can the power follower deliver more than the quiescent current? I'm thinking I could incorporate overload protection to prevent damaging the transducer.

I'm using the power amp detailed here: http://sound.westhost.com/project83.htm, but will run it with reduced voltage & current

In response to armstrom... I would place it in the effects loop of the amp, (i.e after the preamp but before the power amp). That way, if you overdrive the preamp, you will add reverb to the overdriven sound, instead of overdriving the reverb which you might find too muddy.
In fact, the stage center reverb is a sort of effects loop in itself. You could build it from R4 round to R2 , and just place this in your effects loop (this part makes up the actual reverb part, the rest is just buffering and mixing, which will already be in your effects loop). I hope this makes sense.

Thanks for the replies, I am going to try and steam ahead and make a class a mosfet amp, instead of using an opamp, the discrete way might teach me a bit more.
Can anyone tell me how the power is calculated? I understand the P=VI formulas, but not how to calculate what the resistance, voltage etc is. In the schematic given, the power drawn (negating efficiency), is 88W. Is this from 40v, 2.2A and 18 ohms ? Where does the 18 ohms come from?

I'm housing it all in a marshall mosfet head, think it was a lead 100. I received the amp free from someone who couldn't get it working. I have no interest in the head, but will make use of the spring tank. This tank would have a 310 ohm impedance right?

I have basic electronics knowledge, but am clueless when it comes to designing a driver and what effect the impedance of the tank will have on it (apart from higher impedance means it won't drive as well).

Hi,

I'm looking to make a mosfet power amp, to drive a spring reverb unit. This is to go in a modular synth, so I would ideally like it to run off the available +/- 15V supply available. I was looking at this one -http://sound.westhost.com/project83.htm   

How much power do i need to effectivley drive the Springs? R6 would need to be increased i imagine, and could i just replace ground with the -15V ??

If I'm completely barking up the wrong tree here could you suggest something more suited?
I'd like to make it mosfet based, and run off the dual power supply, but searching the forum could find little information.

Cheers for any help i get!

Josh