Pass X-350 with Acoustat 2 + 2

Yep, my good buddy did it last september. Sorry I didn't see your post previously !

He had Krell and Audio research monoblocks with the Acoustas before and the Pass x-350 is the best match he had up until now. Bass response and soundstage are much deeper with silences much darker. At low level, the performance is a premium one. Probably due to the first 100 watts of class A power.

"Probably due to the first 100 watts of class A power." Are you sure of that?

Don't know, not my amp. I can only assess it outperforms ARC classic 150 monoblocks by a lot in the deep bass and soundstage side. Acoustats are heavy drinkers of power and the Pass is a very high current amp, class A must have a part in this !

I don't believe high current requires Class A operation.

Hi Brian, I ran the X 150 and X 600 on Duetta Signatures for some time. I don't think they are worth the price. There are others that have both speakers, but I don't know what amps they are using.

The 350 does run at class A for the first 100 watts. I had another fully class A amp for a time on the Duettas, and that was just great. It filled the stage with beautiful music.

The X-1000 mono blocks run to 128 Watts peak in Class A. Maybe I'm mistaken, but it's hard for me to imagine with that in mind, that the X-350 runs in Class A to 100 Watts.

Checked it out with my friend. As per the unit's manual, the first 75 watts are class A. Therefore my comment remains the same except it is 75 watts instead of 100.

Thanks for all the replies.
We connected a Pass X-250.5 on the Duetta Sigs and the meter immediately went to the rightcorner went we cranked up the volume.
We did not have much hope for the X-350..
We installed a Krell FPB-600 and it drove the Apogees easily. Very nice combination with a JRDG Coherence Series II and a Krell KPS-20i CD player.

Gee, Pass's web site seems to disagree with the manual:
http://passlabs.com/pdf/articles/leaving_class_a.pdf
The article suggest that the Pass X-350.5 leaves Class A at 30 Watts into an 8 Ohm load.

So it will be another "unsolved mystery". My friend drives his 2+2 with ease on his X-350. But yes, the needle meter was also in the right corner on the day he first plugged it. It came back to full center a couple of days after. Full caps !!??

2+2 are not that tough on an amp. They have been tested by a former dealer at 1,97 ohm. Mine drive quite well with a Conrad Johnson 2500A at medium levels and the amp doesn't even get very warm. Never tried at full, don't need to !It's rated at 240 watts. So, it doesn't make any sense that a X-250 can't do the job on 2+2 s. Were the caps full with a couple of days charging before playing it ? Apogee is another story though.

I'm confused. Pass labs X350 or X350.5, completely different amps besides the 150 lbs....

Hi Brian my friend owns a pair of modified 2+2s with a Pass x-350 it is a very good match plenty of control in the base and that,s what Acoustats need ( control ) and here the Pass shows that he is the boss this is not a sissy amp i own a Bow Wazoo XL that i like a lot but it is in no way a match for the Pass and i also own Acoustats 1+1s 82db now thats hard to drive my 2 cents