Probably the only good candidate for 5.1 switching (or for 2 channel switching, as I'm guessing that some of David's three high quality analog sources include either a good CD player and/or a turntable) is the Sony TA-P9000 (the add-on unit to their TA-E9000 pre/pro to provide 5.1 support). It's about $600 from Crutchfield (only online US dealer I could find on Google just now, it can probably be had for less elsewhere). It has three 5.1 inputs (two that are affected by the unit's volume control, one that bypasses the volume control) and one stereo input (which bypasses the volume control). Some HTF members have also had good luck using multiple Radio Shack switchboxes for DVD-Audio/SACD switching, which is cheaper but messier.

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