How long does Plinius SA 102 take to warm-up...

after shut-down? I remember HP saying that the SA-50MK3 took seven day's to sound good which he regarded as the best sound Plinius at the time.
I would recommend leaving the amp on 24/7 for best results. You could save on energy by using the A- A/B selector switch. Listen in Class A, and switch to Class A/B when not listening. Otherwise, I would say that you will get 95% of the best performance at 2-3 hours warm up. 10-15 hours will get you pretty close to 100%, all in Class A bias FWIW.

Great amp BTW, about as good as SS gets.

I recently bought this amp a coupla weeks back. Since then it has been on 24/7. As John points out, leaving it on and in AB (draws < 40 watts) is the default way to go...but when you really want to listen into the recording, I find that only after 30 minutes of class A bias, it has reached near its nominal heat and sound. Not sure about days of class A bias nonstop. It might be marginally better but at 500 watts continuous I'm not paying to find out :)
With my ears/system I get pretty much the peak sound within an hour. It is a marvelous amp. I am totally thrilled with the integration of it with the rest of my gear. I've said this before but I really feel this one is a "keeper" ;)
I believe that the first 5 seconds the amp is switched to A from A/B (of course being on for little bit), the sound becomes significantly better. After about 2-3 hours, I feel this is the peak - with minimal improvement a few hours beyond that. I had never left my Plinius 102 on for several days with class A bias on, so I may not exactly know just what the ceiling limit is on this guy.
After shut down (cold) the Plinius takes 24 hours to sound it's best.
Cool. I had The SA100 Mk 3 ten years ago and loaned it to him and he didn't like it(I wonder why). If it weren't for Audio Nervousa for a BAT Vk75, I would've kept it until the arrrival of a '102.
I think the other folks here have it right...leave the amp on 24/7 if can. If not, 24 hours gets you most of the way there.