@audiofilo123 The upgrade costs depends on who does the work and how far you have to ship depending on where you are sending from, est $1200-1500, but don’t hold me to that. I had a few other small tweaks on min to improve signal path. Since you have no conversion on the 1a, just replacing the main caps and bridge rectifiers and speaker binding posts is a good start, perhaps. A good local tech can do it. Fortunately, the boards and wiring inside is not complicated, which I like.
Yes, I’m quite pleased with the results, thus brining the amp to a level that it beat out my former SS amps that cost more, and puts my mono block tube amps to the challenge to some degree. I like to now rotate this amp in vs. my tube amps every few months.
Yes, having the amp sitting there at true Class-A 50w is like having a light bulb turned up to full light, and if you are not using the light it’s a waste of energy. There is no low-mode or standby power mode, yet the beauty of it is it warms up pretty quick, stays warm, and if you have the desire and patience to start listening after 45-60m its good, even better after 2hrs when the transformer is good and soaked.
Gotta say, I was not expecting the upgrades to do as well as the did. I might look for another 1a myself, sell mine with upgrades, and go even further with a few more tweaks on the next version just because I have local access to all of this. Best of Luck, yes, it’s worth doing if you want true full Class-A 50w like this, affordably.