Pass Labs X1 vs. X2.5

With all the used Pass pre's on this site I've been tempted to upgrade to either the X1 or the X2.5. I've seen both described as having "tube-like" sound. My question is whether the X1 is worth the added expense. Does the separate power supply really help and in what ways. On the used market there isn't all that much difference in price when you factor in the discounts given on the smaller comsmetic version, only around 3200 new! So, if any of you folks out there have anthing to say reguarding these pre's I sure appreciate it. Thanks.

Steven Hebert
Pass Labs "tubelike" I don't think that is accurate, either preamp or amp-wise.
I have an X-1 and it is very natural and dynamic sounding but you cannot get the tube like mids of a tube preamp. It has a little more detail and better bass than the 2.5 worth the difference if that is what the rest of your system can deliver and if that is important to you.
I have an X2.5 and find it very musical. Pass Labs has always been a perfect example of what good SS amps are all about. They are not in any way comparable to a tube amp. One thing you will notice with either the X2.5 or X1, is that the sound is quite "neutral" and the dynamics excellent. As Bigkidz pointed out, the X1 has a little more detail and bass, only because the noise level is lower and so you can hear the music more. But honestly, the difference is less than 5% if at all audible. The dynamics and sound is more or less the same. The X2.5 really sits at the point of diminishing returns and in the entire Pass Labs X pre-amp lineup represents the best value. It also depends on whether you like having one chassis or two. For me, I went for the X2.5 simply because I felt the difference with the X1 was too minimal to pay the extra dollars for; the single chassis helps as well because it conserves space. If I want to have a blacker background, upgrading the power cord would achieve a similar effect.

Zen, hope your still out there. If a power cord would bring the X2.5 closer to the X1, what about a PS audio ac regenerator/conditioner? If the only sonic differences between the two relate to noise wouldn't removing noise level the playing field. Besides, PS device would help my other components as well.
Hi Sjh32,

A better power cord indeed closes the gap a little between the X1 and X2.5, only if the X1 is using a stock cord. Obviously the playing field would not be so level and more so if you put a better cord on the X1. I have tried the PS Audio P300, and the UO and have found the difference to be more than subtle. One thing to make very clear and that is the X1 is a superb pre-amp by any standards- it is indeed a reference amp. Compared to the X2.5, the X1 has a lower noise level, more details and a better grip on dynamics (in other words when musical passages gets a little more complex, it allows the music to expand even more naturally).
However the essence with all Pass amps are still the same which is the same world famous Pass Labs "neutrality" in the pre-amp and a fantastic soundstage with strong bass.

I have compared the Pass Labs X2.5 to every Classe pre-amp model except the Omega and it has trumped them all including the CP-65. Even the PS Audio PCA-2 (a great value), Linar Audio pre-amps, Copland pre-amps cannot measure to the X2.5. No pre-amplifier is completely neutral but the X2.5 has less coloration than all the other amps I have tested. With the $2,000 difference between the X1 and X2.5, one can actually buy a brand-new P300 with more than enough money left to spare for a couple of reference power cords. Of course, if you can afford the X1- go for it because it is quite good. But like everything else, when you end up buying power conditioners and cords, you will be spending another $4,000 more for a difference of less than 10% and sometimes 5%.

Your thinking of having the P300 makes sense because it can help clean up the AC in your system and thus does not just benefit the pre-amplifier alone. At the end of the day, you may just have to do a listening test to determine if this is the amp for you.

Hope this helps. Feel free to let me know how things go in your search.


Keithr has an ax to grind. Must be a solid state phobe. Sorry buddy.
No Keithr is correct, the Pass gear is not "tube like" the X-250 offers a "golden glow" or softer sound in the mids to offer a more tube like sound as do many SS amps that are trying not to sound like SS. That does not mean the amp or preamp is not good, just not a tube amp or preamp.

The X-250 amp sounds slightly different with a tube preamp versus the X-1. With some tube preamps like the CAT, the mids become more alive sounding that the X-1 (this is slight but noticable). Which preamp is better depends on the system, music and your taste.

Happy Listening.