Pass Labs x350.5 & Classe ca-m400 class a power?

Tboooe, of the pairs you've suggested I can only say that I own the X1, and have heard the x350.5 (but that was not in my system). The X1 is an awesomely quiet, very neutral preamp. Nicely extended in both directions, with a very nice midrange. It is one of the best preamps I've ever heard. There is another thread where it was remarked that - in comparison to a great tube preamp - the X1 mids are thin and bare. Frankly I can't agree. I'm not sure how much system dependency the X1 has in placement with other components, but in my system (driving a Van Alstine FetValve amp) I get a satisfactory midrange indeed. Tonal colorations, a real organic presence.

My recollection of the x350.5 is that it is also a fine sounding piece of gear. It was being driven by the X2.5 and I thought the pairing sounded very musical. Maybe just on the shady side of neutral. I can't remember what source was being used, though.

My only complaint with the X1 is that the gradation between the volume click stop positions is too large (about 1.25 dB).

Ghostrider,

As I know, Pure Class A amps draw four-time their rated power from AC line constantly, while Aleph three-time.
Aleph got my vote too !

Cdma, my recollection is that pure class A amps pull twice rated power, but I'll look it up. In any event, as true single ended amps the Alephs (except the 1.0, which has an auxilliary pull stage) cannot leave class A and remain linear.

They do sound great.

Tboooe, both the Pass Labs X-350.5 and Classe Cam-400 are excellent amps that offer great build quality and wonderful sonics.

That being said, I have heard both in my system, and find the Pass Labs amps to offer a "musicality/natural" quality that I did not find in the Classe amps.

At this level of gear, it really comes down to personnal taste and system synergy. The only way to really decide is a home audition, you can keep asking for informed opinions, but your own ear's have to guide you.

Since, I use a Placette dual active line stage, I can't be informative regarding the Pass Labs pre-amps, it's been to long since I last had one in my system.

Historically, I had Aleph's 1 before the 350.5 in my system. When the X-series amps came out I auditioned a 350 and found it quite dynamic/detailed/transparent, but somewhat "cool" and less musical compared to the Aleph's, and therefore it was not my sonic cup of tea.

The 350.5 has all the virtues of the first generation X amps, but adds good taste of the "warmth/musicality" of the Aleph series.

I'm excited that later this week I'm going to be auditioning a pair of XA-100 monoblocks, to power my midrange and ribbon tweeters of my MG-20R's.

Like you, I have gained all the information I could by
talking to other fellow audiophiles regarding the difference between the .5 series and the XA series, but now I have to hear them in my system to really tell what the difference is and will I like the XA's sonics better then my 350.5's performance.

So, I think the time has come for you to set up some home auditions if possible, its both fun/exciting and at the same time a pain in the ass, but the only real way to tell. When I last did this with power amps I auditioned five different amps before I got what I was looking for.

Finally, for my ear's, with my gear, the Pass Labs X-350.5 is just a beautiful sounding piece, and somewhat of a bargain at its price. I believe you got to spend alot more, such as 600.5's or XA series amps, to get a better sounding amp and how much better is open to speculation.

Thanks everyone.

Teajay, as you pointed out auditioning amps is a major pain. So I am trying to do as much due diligence to narrow down the choices before I try and drag home a 100+ lb amp home. Thanks for your input. I really do appreciate it.