Preamp: No audio or sound - one or more speakers

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If your preamp provides a processor loop with pre out and main in/pre in input jacks they must be connected to one another or an equalizer or similar product properly setup and installed on these jacks.

Check your balance control on the preamp or amplifier if it has one.

Confirm tape monitor is not selected if your product provides this feature.

It is possible to turn off individual channels/speakers in your setup menus. Perform a system reset. This will return your unit to the out of the box condition you received it in. If your problem was due to improper setup this should fix it. Check your owners manual for the proper procedure.