PassX-250 vs PassX-350

What is your speaker's efficiency? The 350 will run in class A louder than the 250, and that will affect your perception.

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.

Good for you. Peter (right up the hill from me) might not like me saying this, but it's their fault - Pass Amps are so dependable, buying used is a safe bet.

Bhouser, I was being mean. Actually, I agree with your premise. That is to say, lead speakers should not be matched with golden amps. The catch is, gold can be paid for, or just found, if your lucky and/or knowledgable.

My X600 amps are pushing <1ohm, so there really is a reason for their use. The speakers were not $1500 new.

I went to their site and checked out the feedback issue. Nutella is right. Funny, I never saw that before, and I owned an X150. The X150 is a great amp with lots of spunk and clarity. There was nothing offensive about it's top end. It smoked a Krell KSA. I got nothing but rave reviews with it mated to an 86db 4 ohm speaker.