Cool running amplifier

@imhififan 
excellent. I have one on order, will give it a try.  Thanks 

thanks everyone for the input. Let me add some clarification too:

The compartment that holds the power amp is ~24"h x 22"d,x 20"w. The amp sits on a shelf in the center and there is ventilation under and over. The back side of the compartment is open, but there is a glass door on the front.

I have had a B&K St140 running in it for the past 3 years and heat of the kind Atmosphere mentions has never been an issue though the 140 does idle slightly warmer than I would like, so I would turn the whole rig off when not in use.

In an effort to radically simplify for my wife's use, I want to leave the amp and preamp on 24/7. This way, she just turns on the tv, and the tv remote adjusts the volume. (Seriously, adding one more device to the turn on equation adds 5 orders of magnitude difficulty)  If we will be away for any length of time I will simply switch off the rig.

I swapped in a lm3886 chip amp for a couple of weeks (zero heat at idle or running) and it was perfect heat wise, not so much sonic wise. For now the St140 is back in place and I'll keep an eye on the heat. I would like to improve on the sonics of the St140 though, and with low/no idle heat.

The Sunfire auto signal turn on is an appealing feature. I started looking for an outboard device but so far no luck.

Yes, my preamp will remain on 24/7.  I received the switch yesterday and will try it out today. If I get any unnerving power on sounds I'll abandon the idea. 

I still ill have a search on for a good class d amp or other suitable class ab amp.

thanks again . . . 

ok, so I hooked up and tested the switch. It works great. The amp turns on soft as soon as (ie right after) the tv powers up.  Once the tv turns off, the amp powers down soft again (counted 7 seconds as advertised). Thanks @imhififan 

With this device I can also add a fan if I need. The B&K St140 sounds good for TV, but I'm trying to do some streaming on this system so I would like to get a better amp.  I could use my Eagle 2Cprime which sounds great with the Sttafs, but the face plate is 19" and won't fit through the door.

So now I have a few amps I'm on the lookout for . . .

Thanks @atmasphere .  I'll check it out. 

For grins I decided to try a Crown XLS1500 that I have (it was powering pro/pa speakers in my jam studio). It's a class d 300 watts at 8 ohms. I didn't think it would fit through the cabinet door because it's 19" wide, but I managed to squeeze it in on an angle.

in any event, it powers the Sttafs really well and sounds surprisingly good.  Better bass than the st140 and very nice up the spectrum. It runs cool and has built in fans if needed (likely won't). So I'm going to run with this for now and see how it performs with more music play. I already ordered a replacement for the studio, and the st140 will be listed shortly along with my eagle 2c prime.

thanks everyone.

ok, there's no DSP, just crossover and bridging modes. I had already bypassed all of that.One thing I did do is tune the gain controls (which I originally assumed were attenuaters) which helped a little. 

I'm very, pleasantly surprised by this little amp.