A rear view of the Preamp:
  The XLR jack on the left connects directly to the 'Power' switch on the front panel. A cable from the AC Power Switching Unit plugs into this jack (which only carries 12 volts DC). The Switching Unit switches the entire stereo system on and off; from the 'Power' switch on the preamp. The multi-conductor cable connects to the outboard Power Supply.
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