The unit has 2-channel Preamp Outputs on the rear of the receiver, used for connecting external amps. This unit doesn't have Sub Preamp Outputs.
The rear preamp outputs can be set in the menu to output a full range signal to the rear channels, or a filtered signal to a subwoofer. When set to subwoofer, the output typically has a selectable low-pass filter and is non-fading. You can change the rear preamp outputs by selecting REAR/SUB option under Setup menu of the unit.
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I have a similar hu, but with the third or sub output. Unfortunately it seems I am not smart enough to find the rear/sub out switch in settings to turn it on. Any advice? I have reset the thing twice, and unhooked it once overnight to start from the beginning. Most others just automatically recognized that an rca cable was hooked up. Some of the other settings (caution alarm) don't show up either. Is there another setting I have to have a certain way to access this switch? Really frustrating. I even asked the Sony help guys who said take it to a dealer, or Sony store. This is southern wv, not sure how far I'd have to go. Anyway... All suggestions appreciated.