The pass-through feature allows the audio signal from a Surround Receiver or Processor to pass through a separate stereo preamplifier without any signal modification. This is useful if you have a high-end two-channel system but want to watch video with surround sound on occasion.

To use the Bypass mode on the RC-1580, plug the front channel output of the surround sound processor into the Tape 2 inputs. When the Tape 2 input is selected, the signal from the processor is sent directly through the preamplifier and by-passes the tone and volume functions. Once the unit is in bypass mode, the BYPASS indicator on the front panel is turned on.

Setting a system up this way provides a way to integrate a stereo amplifier to be used as the front channels of a surround sound system. Only the Tape 2 input can provide the bypass function. It requires no additional setup, making it easy to switch between normal stereo mode and surround sound mode by using the input selector.