Review: Pass Labs X-250 Amplifier

Category: Amplifiers

I auditioned quite a few amps before selecting the Pass X-250. Some of my decision to purchase the amp came down not only to the sound of my system with this amp but also to buying a known qualify product from a known manufacturer. I have owned the Kinergetics KBA-75 class A power amp for over twelve years and over the past two years began auditioning many different amps in my home. Frankly it was such a pain in the Ace! The Kinergetics while rated at 75 wpc into 8 ohms, really puts out about 125 wpc. And different power cords made the most improvement on this amp from the 1/4" stock cord it came with twelve years ago to any of the better noted aftermarket power cords one reads about. From all of the amps I auditioned, the KBA really held its own even though it kind of sounds like what most people consider a SS sound. It does have a good mid-range for a old $2200 list price amp. While most of the newer model amps I auditioned where better in all areas, dynamics, soundstage, details, air, etc., these $5000 amps did not really make that big of a difference or blow away the Kinergetics. I was looking for a WOW factor or a feeling that my system was twice as good as before but it never happened. As I look back, there are many factors for that not happening, system and cable synergy for starters. I found that better speaker cables made the biggest difference especially since I had Monster spool speaker wire as speaker cables. During most of my audtions, I was lent mono runs of AZ Hologram speaker cables which easily made a 25% impreovement in all aspects of my systems sound (they should have over the spool wires).

The Pass X-250 is a wonderful amp, and yes there is no perfect amp. The Pass amp was the smoothest, most refined, detailed relaxed sounding amp I auditioned. The Spectron digital amp was clearer sounding than the Pass but lacked the sounsstage especially front to back depth. All the music seemed to come from the same plane. My wife actually preferred the Kinergetics to the Spectron because she felt it sounded more musical. Also the B&W speakers require a high current amp and maybe they are not the best speakers for this amp. I read a review of this amp where the reviewer said it was as liquid as their BAT VK-75SE. In my system, NO WAY, not even close. The VK-75SE is a special amp and somewhat out of my price range but I got to hear it anyway. All of the amps were very good and not really that different from each other just a little bit here and there. You need to hear them side by side in your own system to really hear the minor differences. Most of the reviewers describe these amps better than I can but just so you know, when a reviewer says that a $3500 digital amps matches their $7500 tube amp, they're lying. In all of the amps I auditioned, no amp at half the price of the other outperformed the more expensive amp. I guess you get what you pay for and there really is a diminishing return. System matching was BIG for me. The B&Ws require a high current amp to come alive and the Pass delivered. The Spectron rated at 500 wpc did not sound much louder than my Kinergetics rated at 75 (or probably more like 125 wpc).

The Pass just had a warmer more relaxed smooth sound. At first I thought that the amp was slow sounding but when the music called for more power, the power just flowed endlessly. It was more refined in front to back presentation, with a wider soundstage than the other amps. For dynamic swings, no amp I audtioned could touch it. It has a very natural sound. It does have what some call a lean sound in some areas but again, a minor trade off compared to the overall sound quality. Also note that the Pass was the most expensive amp of them all. I did not get to hear a FPB Krell or Levinson in my system.

In my system the Pass excelled at dynamic swings, serperation of vocals and instruments, sounding very natural, relaxed with limitless power reserves.

The biggest difference in the Pass was when I change the power AC cord from the JPS Labs and Audience power AC cords to the AZ Tsunami power cord a dealer lent me. All I can say now is WOW. See my review of the Tsunami for this amp. The cord change really woke up this amp and added an even more refined sound, dynamics, soundstage and naturalness. WOW again.

Last words, great amp, there is no best amp so find one you like and then added the necessary cables and tweaks to make you system sound the way you prefer your music to sound. Then buy more music to listen to and forget about the system.

Associated gear
Sony SCD-777ES, AZ Silver Ref. IC, BAT VK-30SE, AZ Silver Ref. IC, Pass X-250, Monster spool speaker wire, B&W Matrix 803 series II soeakers.

Similar products
Kinergetics KBA-75, Spectron Musician II Digital amp, Linar Audio 250, Sim Audio Moon W-5, Rowland M-112, Sonogy Black Knight II, BAT VK-500, BAT VK-6200, BAT VK-75SE, Krell KAV-2250.
Kudos for undertaking your project in such a thorough and logical fashion. I'm sure all your efforts pay off now. I have a feeling that in reality few audiophiles adhere to a similar systematic approach when going about the process of choosing, but it does make the most sense, and probably requires the most work. But the way you've done it, not only will you have great sound to your ears, you'll have in all likelihood saved yourself money in the long run, plus have priceless peace of mind about what you've done. Now, you are going to get some of that proper speaker cable and the AC cord for yourself, aren't you? (And don't overlook power conditioning for your sources and preamp.) Enjoy!
Nice rig.Wonder if you have heard the new 803N's?I know they are as expensive as the 801's of the era you menitones but the new nauitlus is quite something.A few people have said they still sound like B&W and aren't worth extra cost(doubling in most cases.But the new $5K 803's have a harmonic refinement and coherence that if you dig the Bowers and Wilkins thing the rest of you excellent rig would sound great with new 803's.Yeah $3K to $5K is a leap but it's worth it.
I appreciate this review. I recently sold my Aragon 8008st. Several friends have suggested tube amps, but I am still disenchanted with them. The possibility of a single-ended triode has also arisen.
I think I am too firmly entrenched in the SS camp right now to make the switch. So I have been considering going with the Pass Labs X 150 but I am concerned about moving to a less powerful amp than the Aragon. For the last couple of weeks I have been trying to decide if I should go with the X 250 instead. Based on the review you wrote I am leaning much more in favor of the X 250. Thanks for your help.
Enjoyed your review. I am intrigued by the Pass eventhough I have only listened to the X150 for a few minutes (and liked it very much). As a small correction, the Pass is not digital. Very few audio amps are digital (PS Audio and a couple others, that's it) - the rest are analog, just like tube amps. Arthur
The Pass is not digital, but the Spectron Musician II amp that I auditioned with the Pass X-250 is.
How did the Linar 250i compare to all the others?
Bigkidz and Nrchy, I remember you both. I've owned the X150, then leaped to the X600. Those two were very different in my system. It just may be the X150 didn't have the reserves necessary for 4 ohm 86db speakers. A 250 would have been a better match. Both the X150 and the 600 are very natural sounding. I think that goes for the whole family. None sound electronic, harsh, sterile, or hollow, like some other solid states I've heard. Pass is the only ss amp that successfully weaned me from valves.
The Linar is a very nice amp but as a new company, you have to think about resale value down the road in my opinion. It was very open sounding, dynamic and natural sounding. I did not get a chance to compare it to the Sim Audio W-5 directly. For the price of around $2500 it is a very good value but compared to the used X-250 at $3000 or so, the Pass is a better amp.
Bigkidz: Are you still running the Pass amp or have you moved onto something else?

As far as the Pass sounding lean, that is probably a byproduct of the load that it is seeing. When reaching this level of equipment, you really need to have a low impedance, low inductance speaker cable. Most speaker cables don't meet this criteria, hence the lack of optimum results and even tonal balance from the amp. Sean
No, sold the X-250 a few years back to raise cash needed at that time. I pulled out my old Counterpoint gear and have been having some fun ever since along with a completely modified Halfer by Johm Hillig at Musical Concepts, also very nice for the price I picked it up at.