I was thinking almost exactly along the same lines at Elevick. Continuing on those lines then:
I'd like to make a few mods to the values posted by Elevick - you need to reduce the SPL at the listening chair by atleast 9dB.
The listening chair is not going to be at 1m away from the speaker; it's probably more like 3m (9.9ft). The SPL drops 6dB for every doubling of distance. From my *assumption* that your listening chair is at 3m, you need to subtract 6dB+3dB = 9dB. Additionally, there'll be absorption from the rug/carpet, drapes, furniture, etc. So, subtract another 2-3dB.
That brings us to 87dB/1W/1m - 9dB - 3dB = 75dB SPL at your listening chair when the 150.5 is outputting 1W.
2W = 78dB
4W = 81dB
8W = 84dB
16W = 87dB
Now, since the music is in stereo, you need to add 3dB to the above numbers. So, if the 150.5 is outputting 4W, you'll be getting 84dB SPL at your listening chair. That's pretty loud - you'll need to raise you voice to talk. At 8W, you'll be getting 87dB SPL. At this point you cannot have a normal conversation in the room.
Of course, this does not include dynamics peaks for which the amp has no class-A capacity (probably by design) & it'll need to go into class-AB & then switch back (just like Elevick wrote).
So, overall you have most of your listening in class-A barring dynamic peaks but w/ this amp you do not have any class-A wattage to spare for dynamics. All your dynamics will be class-AB.
I think Pass' X350 has 75W in class-A - in this amp, you could have some reserve wattage for dynamics in class-A mode.
I'd like to make a few mods to the values posted by Elevick - you need to reduce the SPL at the listening chair by atleast 9dB.
The listening chair is not going to be at 1m away from the speaker; it's probably more like 3m (9.9ft). The SPL drops 6dB for every doubling of distance. From my *assumption* that your listening chair is at 3m, you need to subtract 6dB+3dB = 9dB. Additionally, there'll be absorption from the rug/carpet, drapes, furniture, etc. So, subtract another 2-3dB.
That brings us to 87dB/1W/1m - 9dB - 3dB = 75dB SPL at your listening chair when the 150.5 is outputting 1W.
2W = 78dB
4W = 81dB
8W = 84dB
16W = 87dB
Now, since the music is in stereo, you need to add 3dB to the above numbers. So, if the 150.5 is outputting 4W, you'll be getting 84dB SPL at your listening chair. That's pretty loud - you'll need to raise you voice to talk. At 8W, you'll be getting 87dB SPL. At this point you cannot have a normal conversation in the room.
Of course, this does not include dynamics peaks for which the amp has no class-A capacity (probably by design) & it'll need to go into class-AB & then switch back (just like Elevick wrote).
So, overall you have most of your listening in class-A barring dynamic peaks but w/ this amp you do not have any class-A wattage to spare for dynamics. All your dynamics will be class-AB.
I think Pass' X350 has 75W in class-A - in this amp, you could have some reserve wattage for dynamics in class-A mode.