You'll never know until you, yes, "TRY SOMETHING!"
I mean, are we really going to convince you as to what the differences really are?
I've sold both the Pass and McCormmack lines in the past. At the price points, I like both. The Pass is better overall as a line, and at least a step up to class A! The McCormmacks are strong class B. That's it. The refinement and body of the Pass X series are a cut above, not to mention soundstage, midrange, musicality, etc.
Although, I like the X150 and X350 better personally, especially the 350. The McCormmack has similar tonality, if not a little cooloer sound, with smaller soundstage, less sweet midrange, and not as pristine of a top end. Dynamics are good on both however. Still, I'd try either, and see what you think! You can always sell remember...thus the used market trade thing...
BTW, the Threshold T200/400 is better than the McCormmacks as well, if outdated however. Still, you can find those for $1300-1600 price range used, and they're Superb also.
Although I have not heard Pass Labs amps, I did just recently get to audition the McCormack DNA-225, as well as Theta Enterprise, Theta Intrepid, and Edge NL-10. The DNA-225 had what I thought was a nice tonal balance with a slight emphasis in a narrow band of the upper-mids, and it certainly had a good deal of control. However, its main weekness seemed to fall in an area where I am most critical, and that is imaging and soundstage. Both of the Theta amps bested the McCormack in this regard - the Enterprises by a very wide margin. The Edge also imaged better than the McCormack, but not as well as the Enterprise. The Thetas also were a bit more musical, and had a more airy top end than the McCormack.
If imaging, and depth and width of soundstage, are important to you, the DNA-225 might not be your best option. I am sure that the Pass Labs amps are very nice, but from the amps that I heard, I will be going the Theta route.
Hope this helps, Tom.
Thanks for the responses, guys. I have a T-series amp right now (it's for sale on Audiogon).
I was leaning toward the Pass. It's hard for me to reconcile how McCormack could get that much legitimate power out of a relatively light chasis, having read Nelson Pass's treatise on power supplies, etc.
You asked about McCormack DNA-2 Rev "A"s, but feedback thus far has been limited to McCormack's "in general" and the DNA-225. Read the info (reviews and threads) about the aftermarket revisions by Steve McCormack at SMC Audio. I'm sure you already have though, or you would not have mentioned the Rev "A" in your thread.
My understanding is that these mods turn the amps into something very different than the stock versions, which are the only versions mentioned in the thread thus far.
I'd like to tell you how my DNA-1 Rev A mono-blocks differ from the "stock" DNA-1's, but I've never heard the stock versions. However, I can tell you that I enjoy my Rev A's. I have compared them to Krell 450-mcx, Classe CAM's, Wolcott ?, Mark Levinson 332?, and a few others. I discovered that I would have to spend a lot more to be a lot happier.
I only have experience with the DNA-125, but in my system, used as a spare to back up my VTL mono's, I thought soundstaging was a major strong point, although image height could have been better. I also did not find the tonal balance to be at all thin or bright, a criticism I've read of the new McCormacks. To me, it sounds smooth and deep, with quite good resolution, if not all the clarity or life of my reference, and has power and dynamics to spare. At the price I think it's a bargain, but this assessment can't necessarily be translated directly to the 225 (some experienced listeners have even reported prefering the 125 if the higher power is not a consideration). One thing I'm sure of is that you shouldn't seriously audition your McCormack until it's been on and playing music for at least 2 hours, and the same may well go for the Pass. Also, my 125 works much better with my Satori SC, whereas with my VTL's I tend to prefer the Au24, for whatever that's worth. It wouldn't surprise me if the Pass was better, only not for the same money.
I have an X250, buy it, you will have no regrets. Besides, you can always sell it and recoup your investment if you want to try something else. They sell well because everyone recognizes that it's quality stuff. However, you will not want to sell it.
My X250 is on the way...
I just picked up my Pass X150 earlier this week and finally had some time to compare it directly to my DNA 1 Deluxe for a few hours over the weekend. When compared to the McCormack, the Pass has greater low level resolution, is more detailed without glare or brightness (even at high volumes), has a deeper image and throws a wider soundstage. The Pass also has better bass definition, but not the slam or depth of the McCormack.
My intitial perception was that the Pass X150 was rolled off or soft, not so. I was just used to the forward sound of the McCormack. Also with the McCormack I would have to hunt for the correct volume, the Pass is incredibly consistent and neutral sounding throughout the volume range.
I'll be keeping the Pass. Overall it's a better amp and a good size step up in performance from the McCormack. In this comparison it was only bested by the McCormack in bass slam and depth.
I had both, for a short time, the McCormack DNA-2 RevA & the Pass Labs X-350.
While both are excellent amps,
I preferred the McCormack seemingly complete control and authority over all aspects of the music.
And unless you need a room heater (X-350), the McCormack is also cheaper, cooler, biwire capable, but not as pretty.
Jwilt, Let us know how your date with the X-250 goes.
Jwilt, when browsing some old posts here on Audiogon I came across one about leaving your Pass Labs amp on all the time. I tried it on my X150 recently and can honestly say that to really hear the full potential of your X250 leave it powered up. At least give it a try, I think you'll be as surprised as I was.
Dan: I think that's basically true of any piece of gear - including any amp - to a greater or lesser extent. Obviously no one's going to leave their tube amp always on though. My McCormack defintitely sounds best if I don't turn it off, but the lack of an output mute switch makes me a little apprehensive that the speakers could be damaged if something untoward were to transpire on the powerline while the system was unattended. (Not that I could probably do anything if that were to occur while I was in the room... :-)
Zaikesman: I had heard that some components should be left on to sound their best. I thought it had more to do with their design. As for the Pass, I thought standy mode was sufficient for this. However, the amp must be fully powered up to reach it's idle state. I'm just surprised in the performance difference when doing so.
As for leaving the McCormack powered up, I never tried it with mine. I'll let my brother know about it, he bought my DNA 1 Deluxe off me.