The science of reverb springs

[Don Tillman]

   Date: Sun, 21 Feb 1999 15:56:01 -0800
   From: Rob & Heather Williams <will7370 at tao.sou.edu>

   Does anyone know if the impedance is the same for all reverb
   springs?  

Accutronics is the main, and possibly only remaining, manufacturer of
reverb tanks.  Depending on the model the input impedance ranges from
8 ohms to 1925 ohms, and output impedance ranges from 500 ohms to
12kohms.

You can get data sheets and a great set of applications notes
including recommend circuits from them for free:

 Accutronics / Sound Enhancements, Inc.  
 185 Detroit Street
 Cary, IL  60013
 Phone: 847 639-4646
 Fax:   847 639-4723

   I've played around with them on the bench and I
   guess you cannot insert a signal into them without
   pre-amping it up fairly high, then when it comes out the
   other side it is ready for amplification again.  So I
   imagine it drops quite a bit going through the spring.

What, you wanted the springs to have gain?  :-)

   From: JWBarlow at aol.com
   Date: Sun, 21 Feb 1999 19:43:45 EST

   What I've done in the past is to use the headphone amplifier (those
   extra ones that you get as you acquire a bunch of different mixers)
   to drive the cans and bring the output to a mic input. Is this a
   really bad idea?

It works better than several commercial reverb implementations.  Do it
all in one mixer: use the headphone amp to drive the tank and the mic
preamp to recover the signal.  And adjust the panning so you don't
feed back.

  -- Don