First thing everyone will say is to do a hard reset to factory setting.
Did you buy the A5200 brand new?
What did you hook up to the A5200?
Are the speaker cables loose anywhere?
Are the jumpers tight on speakers (if there are any)?
The A5200 is rated for up to 8V or more, so preamp voltage is not an issue like some lower-end AVRs that are only rated for under 2V.
If you want to talk about "rated", let's be consistent, that is, compare apple to apple.
Yamaha's CX-A5100
RCA uUbalanced Preout...............................1.0 V/470 ohm
XLR Balanced Preout....................................2.0 V/470 ohm
Maximum Output level (0.06% THD)
RCA Unbalanced Preout...............................4.0 V or more
XLR Balanced Preout....................................8.0 V or more
XLR Balanced output is 2X that of RCA Unbalanced output, but the gain is half so the overall result will be the same.
Other manufacturer's such as Marantz/Denon, do not provide the "Maximum" output level, they just provide "Rated output", 1.2 V RCA, 2.4 V XLR but you read online review/measurements, they typically did better than Yamaha's, that's for AVRs, and I based it mainly on those measured by Gene, and his comments. Gene has not measured any recent AVP (Marantz), only AVC (Yamaha) so I don't know if his comments on the AVR comparisons would apply to AVC/AVP as well, I would guess not.
