For information and background;
My PA5 is working well.
Purchased from Shenzen Audio, arrived in the UK in March 2022 and has been in light daily (1-2 hours) use since then.
I listen at low volumes (around 75db). It operates as a power amp, volume set to near max and the system volume changed by by pre-amp (miniDSP flex). Balanced signal throughout the chain. Speakers sensitivity is 89db, nominal impedance is 8ohm.
Amp is switched off once or twice a week, but the power supply is hardly ever powered down.
My amp is not stressed at all. No noise, thumps or concerning sounds and it doesn't get overly warm (never hot).
Watching this thread with interest, perhaps I've just been lucky. FWIW, an amp should be able to take, and hand out, abuse - I'm certainly not suggesting that it should be used the way I do.