Pre-amp input Zin

[Don Tillman]

   From: "Paul Schreiber" <synth1 at airmail.net>
   Date: Thu, 19 Nov 1998 17:40:51 -0600

   I was talking to a recording engineer who statesd that most guitar preamp
   inputs are not 100K but more on the order of 470K to 1M.

   Any feedback?  (pun alert!)

Very true.  With guitar pickups it's generally the case that the
higher the input impedance of the preamp, the better.  The volume
controls on the guitar are typically 500K or 250K pots, so there won't
be much change above 1M.

"Hey man, I measured the impedance of my Stratocaster and it's round
3600 ohms!"  (Or thereabouts, I don't have the exact number on me
right now.)

That's the DC resistance -- the pickup's inductance and capacitance
create a high impedance peak in the medium-high audio frequency range
and so the sound of the pickup is remarkably sensitive to load
resistance.  

  -- Don