Pass Labs X-1000 vs X-600

The Pass Labs X-1000 is rated at 1,000 wpc @ 8 ohms and doubles with each halving of the impedance. The X-600 is Rated at 600 wpc @ 8 ohms and also doubles with each halving of the impedance.

Puchased new, the X-1000 is $24k and the X-1000 is $16k.

I keep hearing whispers that the X-600 is the better amp. If so, in what ways?

Will someone please offer their opinion on these two amps if you've heard or owned them?

I'm considering purchasing one of these two models used. I currently run Infinity Kappa 9 speakers...and they are notorious power hogs that sometimes dip below 1 ohm.

All opinions are welcome.
Mitch4t, in my opinion and other Pass fans familiar with the sonics of X generation Pass amps, the 250 was the best sounding of the single chassis models and the 600 was the the best sounding of the mono-blocks, and were the best sounding of all the X-series amps. They have great dynamics/power but still offer details/musicality. I would not call them warm sounding, but with a very smooth/liquid signature. As far as how they would match up with your speakers, because of the low ohm rating, I cannot answer, I would suggest you call Pass Labs and ask either Peter or Kent who certainly could answer that question. Finally, I would also suggest, if its in your budget, to audition the new X-.5 amps which retain all the brute dynamics/details/extension of the X-series with the warmth/musicality of the Aleph series. Hope this helps.
i used to own the x600. slightly soft sounding. i believe it was their attempt to mimick tube sound with bass impact. i had called and talked to someone at pass labs with the same question you are asking. i was told that listening tests between the two amps showed the x600 to be a better sounding amp. of course they would deny it if they were asked but this led to the purchase of the x600. i would suggest if you get a chance to listen to their newer amps for a sonic comparison if possible. if not i would be careful not to get a preamp that is on the forgiving side. this may lead to a soft and uneventful sound or something that is smooth but lifeless. i see on the auddiogon site there has been a couple of good priced units. there is a upgrade program if you are the original owner for peanuts compared to the price of the x600's new. if you are buying them from a private owner maybe you could get the original receipt for this purpose as this is what is needed for the upgrade to the lastest x600 model.
good luck

Bill and Teajay,

I really appreciate your input on this.

I've decided I'm going to buy a used pair of the X-600's....I just don't have the scratch to buy new at this time. I hope to have enough cash to buy a second pair in another 6 mos or a year...I like to biamp.