switching between two amplifiers; issues of power

Always power off when making connections like this. Then it will be okay to leave on with nothing connected.

The amp btw was fine. For every watt of power you get about a watt of heat. Touch a 300 watt light bulb for reference. That's how much heat the amp has to dissipate, one way or another. If you run one 300 watt amp so hard it gets hot then guess what? Next one will too. Maybe not where you put your hand, but that same heat does have to go somewhere. 

@millercarbon 

So, the first amp is the lovely STA200, outputting 80wpc, and I've got it pushing a 4ohm nominal, down to 3.1 load. The amp does fine at modest volumes. I've been posting about this, from a variety of angles, for the past several weeks. It's a struggle because the amp's sonics are about as good as I would expect to do, for under maybe $3000.00 I could be mistaken and I'm eager to hear some suggestions, but I can't go the direction of tubes in this very hot climate, so we are talking ss or class D suggestions.

Back to the Nuforce: it is not recommended to run this amp on 4ohm speakers, but when I bought my Tekton's I was told the speakers run so easily it shouldn't be a problem. 

I am understanding that class D 300 wpc will run quite a bit differently, owing to crazy high efficiency, compared to SS in the Nuforce. 

1 watt into an 80% efficient amp would seem to yield 1/5 watt in heat?

Hey.  I still own some IcePower 250 modules.

1 - Do not change anything on the input while the amp is on. This includes powering up/down the preamp.

2 - Yes, you may disconnect speaker cables and reconnect them while the amp is on, but suggest muting the audio since you could feel a tingle, or accidentally short the connections.

3 - IcePowers take a very long time to warm up, like 48-72 hours, but they don't cool down in a minute.  You can leave them on except for the short period of time you are disconnecting any inputs OR turning a preamp back on.

1 watt into an 80% efficient amp would seem to yield 1/5 watt in heat?

@listening99

Yes, but they have a fixed idle power you are not accounting for, on the order of 5-10 watts. So take the efficiency and add the idle power, more or less. :)

In your example, it’s’ probably something like th 5W idle + 1/5 W = 5.2 W.

The excellent and more powerful Job amp should be on your list IF your new amp does not meet expectations. We have one in the studio, it is rarely powered down.