What could I expect to hear from a Class A amp?

Class A amps should run 24/7 for maximum thermal efficiency. By turning them on and off shortens the operational life considerably due to convection. In a way its like a light bulb turn on and leave it on it will damn near last forever as opposed to the constant on/off cycle.

One of the reasons for listener fatique is due in part to the on/off cycle. Run it for a solid week of 24 hour operation and you will hear the difference and the difference you paid for a Class A amp.

In fact I run my all my amps regardless of Class of operation 24/7. They just sound better by being continually on. Many of the newer amps have a standby feature which allows to the unit to stay on, but at a less power consumption.

Obviously say a Class A amp running at 60 WRMS per channel, if its pure Class A it is drawing 300 Watts at the wall. Something to consider in regards to your monthly power bill.

There are trade offs in using Pure Class A amps, but over the years I have found, for me it is well worth the penalties that come with Class A operation.

The dealer I am referring to told me, "I am not an audiophile." He has a huge collection of discs. He sells monitors of his own design to recording studios where he knows recording stars by first name. Of course his amps and preamp are on all the time.

They sound wonderful, and to virtually all ears the music is as good as it gets. His Full Range speakers are spooky good, much better than stock. I have watched his gear and speakers improve steadily over the year.

I have a couple tell tale discs I took with me on one of my visits. One is a cathedral pipe organ recording. I told him you can hear the organist pull and push stops between pipe changes. It is something I take for granted.

Remember, he is using Nelson Pass's best 2 part preamp, XA 100 monos, and 600.5 monos. Even on listening for those wooden pegs, I could not hear them. On another disc, a brass quintet. The tuba and trumpet were recognizable, but the other three horns just became a background blend.

Where the XA amps excelled was on simple fair, such as voice and guitar.

You know these arguments can go on and on. SET/single driver adherents think we are both idiots.

I should have made it clearer. The 4-5 hours is going from standby to full power on. The standby mode is just not enough. So to rephrase the question, did you find the standby mode insufficient to let 30-60 minutes at full power to finish the job?

On separate issue, would all that heat for 24/7 at full power take toll on the circuit board? Of course the counter arguments would be the on/off as you said, and the expansion/contraction fatigue cycle due to the hot/cold. Do you know what's the typical age of a class A amplifier before the heat kills it. At least the XA60.5s are hot but not that hot.

I'm confused about the comment on Henry Ho. The DAC is either positioned between the transport and the preamp, or is part of the preamp itself. Yet we are talking about the amplifier here. It comes across that you actual benefit from improvement to your source instead.

My class A runs damn hot.
It really needs a week of warm up before sounding it's best?
On the advice I got calling the Sugden factory, I turn mine off between listening sessions.

"On separate issue, would all that heat for 24/7 at full power take toll on the circuit board? Of course the counter arguments would be the on/off as you said, and the expansion/contraction fatigue cycle due to the hot/cold."

Spatine - the only perishable component inside of SS amp is electrolytic capacitor (other than ON/OFF switch). Rush current does nothing to electrolytic capacitor other than heating it slightly (very short time and very low ESR) in spite of large momentary current. Electrolytic caps die of dehydration. Each increase in temperature of 10 deg Celsius cuts their life in half (water evaporates from electrolyte). Eventually drier capacitor has higher ESR and starts heating up to the point of runaway. In critical application (lots of current) they get to thermal runaway and explode (they have fuse to relieve pressure). The other way to damage them is to leave them without voltage for years. Aluminum oxide layer that serves as isolator is eaten by electrolyte but presence of voltage builds this layer back.

Fairy tales about rush current (turning ON) damaging equipment comes from two sources. First is the bulb or tube that breaks on power ON since cold filament has many times lower resistance. Second is the fact that if you do anything around your amp like for instance moving speakers while amp is OFF and create short it might damage amp when you turn it ON and you will blame turning ON (rush current).
Sometimes also mechanical component tends to break at start-up like for instance computer's hard disk.

Circuit boards, resistors, film and ceramic caps, transformers etc last forever even in extended temperatures. As for semiconductors - as long as they operate at sensible junction temperature (let say under 125 deg C) they also last forever. There are electronic circuits with semiconductors being turn ON/OFF hundreds times a second and they last for over 25 years. Simple example of it is seven segment multiplexed display.

As for sound being optimal after a week of continuous operation - it's possible. I don't have class A amp, don't have experience with them and perhaps less than "golden ears".

People who calculate reliability are probably ready to kill me for saying all this but statistical analysis they use is something else. When I walk with my dog we have statistically 3 legs each. Also statistically tattoos are causing motorcycle accidents.