Pass Labs xa - .5 amps

Mozvz,
I haven't listened to the X250.5 or X350.5, but I own the XA 60.5. The pair of 60.5 sit on stereo rack. So it does not matter to me if I have 1 or 2 amps. The reason I write is that I don't think I'll ever come back to Class AB amp. after living with Class A amp. The mid-range is more much natural, meaning less harsh and more fluid. Sound texture is far more realistic. To me the sound of each note, let it be vocal or instrumental, is a continuum of frequencies with the dominant ones being more present and hanging around a little longer. The subtle frequencies thus have shorter transient. Class A amp., at least the XA 60.5, let me hear the whole spectrum of frequencies as opposed to mainly just the dominant frequencies. The result is a truer sound.

From the power standpoint, 60 watts/channel means 120 watts for my full-size speakers. The pair of XA 60.5 are actually more dynamic, with that headroom you are talking about, producing more slam yet distinctive drum bass than a 150/300-watt amp. they replaced. To avoid talking down on a well respected amplifier, let me say that this former 150/300-watt amp. of mine came highly recommended by Stereophile who put it in their Class A category (this is review rating, and is not the "Class A" amp. I referred to earlier). Now that should tell you something about the XA 60.5.

If you choose to buy a brand new pair of XA60.5, it will set you back around $11K. To be fair I must preface that my earlier comment implies proper caliber for the remain equipment right down to cables and connectors. I should also said that the surprising factor, in my case, is actually the vibration/isolation platforms. It's like getting an upgrade on your equipment if you choose the right platform. It's comical that the platform I used under my power conditioner costs twice as much as the power conditioner itself. Yet that's the add-on that makes the most difference. Just about everything would have to be "right" to avoid wasting money on buying the XA60.5 or any amplifier with this level of performance.

Hey Tvad, do you find having to wait some 3-4 hours from standby to fully power on mode before your XA 60.5 reach their full potential. May be I'm being too picky, but the half to one hour warm up just isn't enough.

It appears that a few people on this board are looking for non-commercial bias and honest opinion about how to choose a Pass amplifier. I would suggest that you review messages previously written about Pass XA.5 and X.5 series on this board, find ways to actually audition the amp. before consider buying, and call Pass Lab to get their advice on what amp to get given your existing stereo equipment. I did have to do my homework before buying anything. My few observations and some common sense are that: (1) People who are happy with XA30.5 tend to have smaller speakers; (2) Pass Lab personnel themselves when called upon are too proud to not give you what's right as opposed to what's profitable to them; (3) Class A amplifiers will heat up and will require some warming up time if you want good sound, but at least the XA60.5 of mine don't burn your hand like some other amp. would have; (4) All amp. regarding classification will go into clipping if you drive them that hard, but why would anybody want an amp. under-rated for the rest of their equipment? I can only tell you that the XA60.5 can certainly run enough full-size speakers, along with previously mentioned perks. As to the XA30.5, you must do your own homework, and especially don't just listen to anybody.

My earlier comment about sound superiority when compared the XA60.5 against a Stereophile Class A amplifier was based on using single-ended connection. My preamp is also in the Stereophile Class A category. Its manufacturer has a radical viewpoint that balanced connection does not make a difference in light of their well crafted circuitry. So back then there was that lingering thought about perhaps my preamp could be eclipsed by an different preamp of equivalent pricing but with balanced connection. I am known to be picky and difficult on just about anything, even as my preamp sounds pretty good and is well respected by enough professional reviewers. Yet after getting the pair of XA60.5 and am so surprised at their performance, I have resigned my concern.

The point here is more about Class A amplifier than about Pass Lab. I just dive right into Pass because they are the measuring stick and the bridging gap when people attempt to compare solid state amplifiers to tube amplifiers, with each category having its own strengths. But I would think a few upper-end Class A amplifiers beside Pass could somewhat portray what I am talking about.

RmRobinson1957,
Although haven't listened to Krell I believe in Krell's excellent handling of the bass given the number of acolations they receive. It might come down to your expectation for the total package, from top to bottom of the frequency range. As for me, I can tell you that I have not heard of any Class AB amp. coming near to realism that a Class A amp can, such as my XA60.5. Elsewhere in this thread I already described what that means. As to the bass itself, my speakers have their own powered subwoofers but I don't crank up their volume because too much bass would cloud out everything else. Leaving the sound to its natural setting, I have no problem at all getting distinctive bass that pound the ground when the music calls for it. As to comment about preamp, mine is the Bryston SP2 playing music on the 2-channel bypass mode. Bryston is known for bass. Perhaps that helps; perhaps it doesn't make a difference to the Pass XA60.5.

Discussion lately about Pass XA.5 seems strange to me. Typical comment about Class A amp is that there is insufficient brightness, and not the other way around. I thought my XA60.5 does a fantastic job preserving the fair balance of upper frequencies relative to the mid and lower. An over-emphasis on upper frequencies grab your attention at first, as it gives you the illusion that the equipment is precise and detail in producing the sound. But you soon find out that the sound stage is hem in and the sound is rather harsh. I don't see that in the XA60.5 at all.

As to the lower frequencies, if you are looking for that extra dance club banging so that you can shake with the beat then there are many significantly less expensive amplifiers that can do that for you. As to the XA60.5, I definitely feel the jolt when the particular recording actually calls for it.