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

Bryon,
Thanks.

Ok, the room is 19x11.5 feet, ceiling 9 ft. Speakers can be placed anywhere i.e. along long or short wall.

CD dCS Puccini, PreAmp (planning Pass labs XP-20), power amps (planning XA-60.5, may be XA-100.5 or the 350-th).

Cables choosing from XLO LE or Shunyata Anaconda CX.

I listen to jazz, blues, rock, classic. No electronic and acid.

Sergei

I recently visited a Pass dealer, who explained that Pass amps are more alike than different, but are rated differently. IOW, the class A amps do indeed cross over to Class B beyond their rated class A power. A Pass class A model rated at 100 watts/channel will deliver, perhaps, 300 watts, but in class B. The rating merely tells you how many class A watts you'll get, not the amp's peak output capability. I'd speak with a Pass dealer or even Nelson himself before you decide.

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!