PassX-250 vs PassX-350

BTW- I am using Martin Logan Ascents.

Krelldog-

I use an X-250 with Martin Logan Aerius i's, along with a Pass X-3 for rears/center. They replaced Bryston 4B-ST & 5B-ST's. The Pass amps are sonically miles ahead of the Brystons with these speakers, even though the similar specs do not suggest that they would be. I considered the X-5 or an X-150/X-3 combo before buying the X-250 & X-3, and talked to Pass Labs about the speakers I was using. They knew the Aerius well, and definitely recommended going up to at least the 250 for the front mains.

With ML's, you want current - lots of it. I don't think you could ever over-amp these things. But I find the 250 can handle driving these speakers that drop to 1.2ohms at 20khz quite well.

Would the 350 do it even better? - Probably - just as RangerAudio suggests. I just could not justify running $2300 speakers with a $9000 amp, nor could I afford it. Besides, I bought my pristine 250 used (right here on the 'goN!) for a great price. I have no regrets or desire to upgrade above it now.

FINAL NOTE : Just yesterday I replaced my Aerius with Talon Raven 2002 speakers with Khorus-X/2 CMRC crossover upgrades. So far, the synergy of this Pass amps/Shunyata Lyra cables/Talon speakers combo is proving to be quite magical and dynamically powerful. These are not, of course, electrostatic speakers, so they are an easier load on the amp.

Hope that helps,
Bob Houser

Thanks Bhouser,and everyone else for the advice. The X-350 is 9K,but the used price recently is around 4K(actual ads)If I sold my 150 it might only cost me a couple grand more for the 350. Regardless I'm sold on Pass,and my decision is narrowed down to the 250 or the 350. I probably can't go wrong with either.

I spoke to Peter at Pass and he helped me with some of the differences between the amps. The x150 and x250 have similar circuit designs with only some localized feedback around the output stage. The X350 and larger amps have the zero negative feedback characteristic which adds to their lushness and overall neutrality.

Nutella, that's new to me. I never heard the X150 and 250 use feedback while the larger ones don't. I do know, for a fact, all X amps employ a small amount of feedback in their supersymmetry circuits to help equalize distortion matching. As far as I have read, that's all.

Still, when I switched an X150 for X600 monos on 4 0hm speakers, I noticed more than the expected bass improvement. the midband was both warmer and it had more body. It is my guess the class A operation of the X600 accounted for the different performance. That is why I am voting for the X350 in Krelldog's case.

Bhouser, I am running $1500 speakers on $16,000 amps. If the speaker does everything you want, and it asks for the power, you feed it.