switching between two amplifiers; issues of power

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.

@tomic601 That's interesting... Mrdecibel convinced me to stay away from the Job, suggesting it would have similar difficulty, owing to the low impedance of my speakers, dropping down to 3.1 ohms, according to claims by one owner of Tekton Moabs. I also understand they not longer make the Job 225, and I understand this might be related to design flaws and reliability. I've heard a variety of reliability comments on the Job, and your comments come out on the positive side...

It seems the Job would have an easier time supporting LARGE LOUD bass notes, like the kind that open the live version of Styx's "Snowblind" (song 5, on the first disc), on their Caught in the Act, album. I'm actually more 'asking' if the Job amp would do better, specifically in terms of handling LOUD BASS and in managing heat at louder play. The Nuforce STA200 is wonderful, vivid, clear, particularly skilled in rendering the music and imparting a feeling of the space, but things shift a bit when  I'm asking for average delivery levels of 90+ db, with peaks in high 90's or above. Give it an hour in that territory and the heat sinks are VERY hot, maybe not burning, but very hot, and the entire chassis is also hot. I've always brought the volume level down at that point and things seem to cool well.

I want to clarify that aside from the heat, the other issue is that I want to be able to play the very biggest bass notes without difficulty. The NuForce does not play Royals by Lorde particularly well. I do not pursue this kind of music but rarely, but if I'm going to buy another amp, I think I want it to be able to handle the big stuff. That's the primary motivation, although I'm intrigued by class d. As mentioned, things are too hot in my home for tubes, during the summer. This is why I've got what some are reporting is an excellent low-cost decently powered class D amp heading this way...

A couple of caveats. I had (still have) a similar situation. I have a pair of tubed mono block amps that I use for serious listening and a SS amp which I keep as a backup or use when I just want some background music on but don't want to put hours on my tube amps. Both are connected through a Beresford switch box to my single pair of speakers. When I want to swap amps or do an A-B comparison, its simply a matter of throwing the switches on the Beresford. DO NOT CONFUSE THIS WITH A SPEAKER SELECTION SWITCH BOX. The Beresford is specifically designed for the exact purpose of swapping amps to a single speaker load. Also I believe i read somewhere that tube amps should never be left on without a load connected. This is consistent with the Beresford design the circuitry of which  includes dummy load resistors to prevent a powered on tube amp from seeing an open load. 

J.Chip