I have a Pass Labs X350.5 in 7/10 condition - amp is in superb shape overall, but does have a few small lines/nicks on the face and top (shown in the photos). All original factory packing as well.
I purchased this amp after a great deal of research in the ideal amp for Magnepans (which, of course, are low sensitivity and need lots of current also). I specifically chose it over the XA series as a better match for Magnepans (and many other speakers), and definitely prefer it to the XA60.5s I had previously. (It's a myth that the Pass XA amps are superior to the X in all scenarios.)
As the reviews I quote below point out, this amplifier, besides being a serious powerhouse, is as refined as anything out there. As a guy who's owned over 30 SET amplifiers, I agree with the statement below that it has the delicacy of a "small triode amplifier." The typical rule that you lose something in the refinement department as power increases (due to the need for more output devices, etc.) definitely does not apply to this one. Apparently Pass worked hard to make the X350.5 the best in the line, and it shows. (The downside? Well, it's huge, hot, and cost $11,500 new.)
I bought the amp from a well-reputed dealer who shipped it to me with the amp in the factory packing and the factory outer box inside yet another box, strapped to a pallet. It may be shippable ground, but just barely (the amp weighs 132 lb naked so packed is going to be very close to the 150-lb ground limit).
I will ship it freight anywhere in the CONUS for a flat $250. Local pickup is encouraged and will be given preference for a time.
Buyer must cover any PayPal fees (wire payment, certified checks, personal checks after clearing, and PayPal "Personal" all welcome).
Some professional review comments (which I collected in my own research prior to purchase):
"Though the XA.5 series seems to get the most press and accolades, the X.5 series can be just as alluring and satisfying with the right speakers and supporting components."
[Pass Labs' comments]: "Class A/B amps are optimized for maximal wattage and in general have higher rail voltage and correspondingly lower current reserves than the identical sized Class A amplifier. Additional current reserves are beneficial in loads of low impedance and with woofers that require lots of control. Higher voltage is beneficial with speakers that are already well damped or those which have capacitive reactance as a big part of their impedance plot (many panel speakers).
If I were taking the over-simplified view of the world, speakers with high "Q" would first audition with class A amps and those of low "Q" would first audition with A/B amps. Speakers of low impedance or high sensitivity tend to get auditioned with the XA.5 amps. Speakers of more modest impedance and low sensitivity tend to get auditioned with the X.5 amps."
"With the X.350.5, you can sense the tightness of the leather and skin on each drum. You can feel it in your chest and ass as the percussion moves across the soundstage. No overhang. No huffing and puffing. Speed and dynamics are as good as it gets. The X350.5 keeps up and executes without flaw."
"I have mentioned that the X350.5 has an incredible ability to produce proper weight and timbre. Check out the Guarnerius violin. You can almost taste and smell the rosin as it pops off the bow and strings. Piano is one of the most difficult instruments to record and reproduce. The harmonics are spot on. The dynamic interplay between the two is amazing. Reach out and touch! You are there!"
"The Pass Labs X350.5 amplifier is an extraordinary achievement for both sound and execution. When properly matched with speakers that have synergistic voltage, current and power requirements, it can compete well with any solid-state amplifier in the market. This includes Pass Labs own XA.5 series of amplifiers, which have received so much attention and rave reviews. The X350.5 can easily be paired up with a variety of tube preamplifiers to produce a sound that exemplifies the merits of both solid-state and tube design."
"The X350.5 is extremely quiet, with no perceivable noise floor, has the dynamic agility that in my opinion, is literally in a class by itself. Its bass response is first rate in authority, weight, speed, and tunefulness. Yet, through this high-octane athleticism, EMERGES THE SOUL OF A SMALL TRIODE AMPLFIER. The midrange remains beautifully rendered, subtle nuances and textures remain intact, and images are expansive and remain so, even when the amplifier is pushed hard. Again, not a me-too variety solid-state amplifier, far from it."
"The solid-state X350.5 does, indeed, sound similar to a fine tube amp, both in its general tonal character and in the way it “tracks” musical phrases (more on this later). However, the X350.5 offers much more than tube-like affectations."
"The amp is “liquid” in its ability to sound grain-free and non-electronic, and is “compelling” in its ability to reveal musically interesting nuances in the source material. Since much of the music I listened to with the X350.5 was
likely being handled via its first 40 watts, I believe this smoothness and nuance can be attributed to the Class A effect."
"Another similarity to tube amplifiers is the X350.5’s ability to track musical phrases in ways that many solid-state amps just seem to short change. Rather than cycle through a pattern of the “picking up” and the “letting go” of musical notes, the X350.5 seems to hold onto them better, longer, and more completely than most other solid-state amps in its price range."
"Considerably more than merely good sonic performance awaits X350.5 owners. It provides truly compelling listening sessions with your music collection—fatigue-free, imagination-inspiring, emotion-filled listening sessions. Its prodigious power, natural tonal balance, and liquidity impart a solid foundation to even the most demanding music while caressing delicate passages with a silky fine touch. I can’t think of a more powerful and non-fatiguing amp close to its asking price."
Enjoy The Music
"Pass Labs claims that the X350.5 brings more 'spatial development and detail' than with any of the smaller X.5 series product to the reproduction of music. They go on to say that the X350.5 is capable of exposing very subtle tonal shading in recordings, even though they consider it their 'workhorse stereo Class A/B amplifier.'"