IRF510 or LM386 as current boost for reverb driver?

[petemoore]

  I've got a Stage Center Reverb on perfboard working on a 14/0/14 Vdc PS.
  I think I want lower impedance on the driver output, to help me decide, I want to put lower impedance on the output.
  As far as I can tell the DC resistance of the tanks driver condenser is a useless measurement @221ohms.
  Prehaps if I put a current drive on the output [mosfet source follower w/28V supply], or an LM386 with 14v supply ?
  ie...tack a buffer type stage on the end of the reverb driver circuit.
  Any suggestions welcome...
 

[mojo_hand]

Unless you're using an LM386N-4, the max PS voltage is 15, so you might want to think twice before setting it up for a 14 volt supply.  Unless it's a really well regulated supply, anyway.

But I'm not sure whether you need the lower output impedance or not.  You say that driver element in the tank has a DCR of 221 ohms, and the Z at 1KHz is going to be higher than that, probably several times higher.  Something like a 386 wouldn't be able to swing enough voltage to drive an impedance that high, nor would the current capabilities of a 386 be especially helpful.  So I'm going to stand by my earlier recommendation that you find out what model of tank it is, or, failing that, you could try designing around a *wild guess* of 700 ohms input impedance (Accutronics-made tanks, with a DCR of 221, could be anywhere in the 250 ohms-1925 ohms range).  700 ohms might be too far off to work very well, but at least it's in the ballpark, and you could adjust the design after a little trial.

[petemoore]

  I tried calling and emailing to find out something on the condenser impedance.
  Failing that I figure just go for low output impedance.
  Right now I have an IRF Mosfet [came out of a thing], which has a 4k7 resistor on it, whether that's low enough I don't know, it's not gettting hot and seems to be driving the tank.
  The 'mess' is speread all over...guitar/cable/unshielded input wire/board/output to tank wire/no shielding on the return either...grounded/shielded cable going to the otherwise noisey test amp [computer speaker.
  I think with major cleanups [now that it is actually working and sounding pretty tanky], shielding and grounded enclosure, separate supply box etc., it should quiet down and be nice. 
  I have a new IrF510 but the IRFxxx mosfet I found seems to work fine, it's a little smaller, had the pinout marked on the board it came out of!