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

Detail without fatigue.
Smoothness without the mush.

Could somebody please comment about the 24/7 operation needed for Class A. Typically I heard that you want to warm it up for 30-60 minutes. Yet it seems to take about 4-5 hours before my ears could not distinguish a difference.

I definitely agree about the non-fatigue factor since your brain does not have to fill in. Before getting the XA60.5, it's like a love-hate thing I have with the stereo. I must listen to it because I love music. But about half an hour later, I got tired, somewhat disappointed, and turn on the TV instead.

Ferrari, that would be calling me a fibber. Like I wrote, I used other conventional amps, including Pass Labs fair. Nothing ever came close, including the latest class A ware that approaches the fierce speed of resolution to the faintest nuances offered by my amps and preamp by the same maker.

I hope you don't mind me offering just few pointers when auditioning class D amps. First of all, don't be sure your system is conducive to class D amps. Secondly, there is a quality hierarchy applicable to class D amps as you found out.

On the first point, I have had the same monos and preamp for years of listening. During that time, the resultant sound moved through a series of personalities. At one time, it was airy and whimsical. Another time it sounded warm but focused.

After eschewing commercial speaker cables, and employed the short ribbons I use now, the sound took a revolutionized step. I upgraded my non oversampling DAC which I sent to Henry Ho of H2O to work his genius on. The stage stretched fore and aft, bass grew in heft and musicality, highs perfection, mids as natural as it gets. The last amazing surge in fidelity occurred when

I could go on and on. If I thought any of the class A amps could do me more, I would be happy to buy them. The knowledge Henry makes class D amps and class A preamps to be as squeaky clean as can be, I knew there was a way to harness the best possibilities.

I talked with the manager at Sugden.
His opinion is the amp needs 10 minutes warm up time.

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.