Pairing problem with amp/speakers???

Have you hooked up the 1266's directly to the VSX52? If the speakers fade out at the same volume than it is probably in the speakers, if not than it's probably the XPA.

XPA halves the power onto 4ohms and quarters onto 2 ohms.
It has neither powerful transformer nor good filter caps in the power supply and no room for current reserve. You should use for this amp tube-friendly and efficient speakers. Power cut-down is to prevent clipping and save your speakers.

Don't even think of hooking up XPA directly to your speakers. You may jeopardise their condition and safety.
In the best case the clipping protection circuit will block output stage completely.

XPA is cheap and popular and easy to sell and replace with larger poweramp. Good budget options you may find among digital amps that are also made in China and have better 4-ohm drive capabilities.

Thanks. Any advice on the amp (brand and output) that I should replace the XPA with? Any help in the right direction is appreciated. I have about $1500- $2000 to invest in a new amp. Thanks again.