going Pass Labs, do I need "Class A " ?

Bondman is correct. Stereophile's measurements of the XA30.5 confirm this...

While the XA30.5 may give 30Wpc into 8 ohms in class-A (14.8dBW), the distortion at this power level is low, at 0.015%. The amplifier doesn't actually clip (defined as the THD reaching 1%) until a much higher power level: 130Wpc into 8 ohms (21.14dBW). Even higher powers were available into lower impedances before clipping: 195Wpc into 4 ohms with both channels driven (19.9dBW), and 332W into 2 ohms with one channel driven (19.2dBW).

Having said that, there are design differences between the XA series and the X series that go beyond biasing. IOW, the XA series isn't simply the X series with a higher bias setting. And that is reflected in the difference in sound, IMO.

Sergei - I noticed you added the XA100.5's to your list of possible amps. IMO, that would be the best of both worlds. I've heard the XA100.5's, and they are glorious sounding. They are considerably more money, but you may be able to find them used. Reno Hifi is a good place to start.

Bryon

Bryon,
thanks once again. The thing is that I'm located in Moscow, Russia where pricing for PassLabs can be killing. I like used offers at A-gon and would easily make a trip to the US for collection.

The issue is 110V used in the US while it's 220-230V in Russia. By the way, is it hard / easy to make it operational at 220V out of originally designed 110V?

A transformer could be used but I would like to avoid it, if possible.

I would go with Class A if you can afford it. Yeah, that price over there in Russia might be too tough. But, here in the US, we have much higher prices for high end European and some high end Japanese imports compared to Europe and Japan. I don't know where these distributors get those prices from, but I hope there's a logical explanation. Anyway, that's another topic for another time.

Good luck!

I have the XA 60.5. didnt listen to the 350's. The XA60.5 has been a revelation in my system and has plenty of bass. Very tight and controlled. I think many times differences are due to interactions between amps front end and speakers. Dont make a decision from the 30.5, it was not enough class A power to run my Dynaudio speakers. The amps would go into AB. The 30.5 has plenty of power to run the speakers but the sound character changes. I would advise you to check out the 60.5.

Sergei

As far as I know and i'm also from a 220v country [Israel] the xa range can't be converted internally from 110v to 220v and I don't think you want to use a transformer which might kill dynamics. Try to look for a used one on audio-markt.de [you have a 60.5 listed there currently].
I own a pair of 60.5 and they are glorious. Good luck anyways.