DB Systems has used equipment for sale from time to time.  All items are refurbished and tested to new specifications and come with factory warranty.  Prices are approximate depending on the state of the unit.

As of My 10 the following are available:

DB-6 Stereo Amplifier 400, DB-6A 700, Upgrade to DB-6A available
  **We have 1 stereo DB-6A amplifier available.    Conversion to mono is $40.
   **Pair of DB-6A-M + mono amps..  Updated to the current performance, with the "+" upgrade for triple power supply capacitance (126,000 ufd).  1700 (Retail 2906}**
DBR-15B/2A Preamp and Tone Control on a 19" rack plate  1100 .
DB-1B Preamp 500 up
DB-500e  Crossover--special 3 channel crossover with  24 dB L/R low pass (summed all three channels), 12 dB BW high pass, switch for Academy rolloff.  200 + psy
DB-3-24 In Phase Crossover 400 (requires DB-2A Power Supply)
DB-4B Pre-Preamp 150
DB-5 Tone Control 420
DB-7 Phase Inverter 170
DB-2A power supply 125