Review: McCormack DNA-250 Amplifier

Category: Amplifiers

First a disclaimer; I am neither an electrical engineer nor an artist. I am just a consumer of fine audio like most of you, so my review is based on my listening experience. I mostly listen to jazz and rock, but sometimes I will put on a classical recording.

I've had my Ohm Walsh 5000's for about 9 months and was powering them with my 1991 Sumo Polaris II, a Bongiorno design that is still considered a fine amp, which is rated at 130W pc. Since the spec sheet for the Ohms recommends no less than 80W nor more than 350W I was on the lower end. I selected the McCormack based on the reputation of the previous products and price. Since McCormack himself at SMc Audio offers upgrades of its predecessor the DNA-225 (indicating that it can benefit from upgrading), I tended to believe that when C-J bought the company they took the 225, made some improvements and called it the 250, but left the essential design elements of Steve McCormack. Keep in mind that in my way of thinking the hierarchy of importance in audio are the speakers, followed by the preamp, with the amp being the least contributory (assuming the power matches the speakers needs).

The price was listed as being on sale for about 35% off, which may be a sales tactic and hence the usual price. There are no other dealers than Spearit Sound, but their service was excellent and they talked to me on the phone first. Fill in the card and you have a 3-year warranty. It arrived by UPS unscathed, and carrying the 72-pound package up the stairs was not bad. Side by side, the McCormack dwarfed the venerable Sumo and at 53# it's heavy, especially at the front. It's all strictly business with the minimalist styling and lack of glowing power meters and other touches that would be window dressing. One set of gold unbalanced RCA inputs on the back with plugs for one set of speakers. The overall impression is one of massive engineering and quality. After plugging it in, there was an annoying hum that turned out to be a ground loop, no fault of the unit. After trying various grounding maneuvers, I finally got an extension cord and plugged the amp only into another outlet. This isn't supposed to help, but the problem was solved.

My review included use of vinyl, CD's, SACD's, mp3, and some fm. Overall, I would say that while the Sumo was musical, the McCormack was both musical and muscular. It was as if my speakers got larger, capable of moving more air especially at lower frequencies. The speaker specs say down to 25hz and now you can hear it. Although I found it hard to believe the sound stage was expanded slightly side-to-side and more noticeably front to back. Put on The Doors "Crystal Ship" and it sounds like I'm in a room the size of my high school gym. There are layers of pleasant vocal harmonics, thanks to my tube preamp. Even the mp3's on my iPhone sound great, though these are the Purple Chick versions of Abbey Road and have a high sampling rate of 1411 kbps. FM is particularly improved to the point that it becomes quite pleasant.

As luck would have it, I left the unit on all night- it was just lukewarm in the morning, loafing along which is good since this isn't standard rack width and air currents are needed around the unit. Any criticisms? Well the power on led is a bit tiny and hard to see when it's lit, but honestly that's it. This is an ultra high quality, powerful SS amp that is capable of powering even the least inefficient speaker designs to perfection. It mates well to my all tube preamp, providing powerful clean bass notes. Was my Sumo excellent? Yes. Does the McCormack sound better? Absolutely. Was it worth it? For me, yes since I could justify it as a 20+ year investment. What other electronic item can you say that about?

Tested with ProJect 5.1, carbon graphite arm, AT33-EV, Raphaelite PM 1.1 step up transformer, NAD PP3 phono amp for vinyl; Ming Da MD300 APS preamp with NOS 6SN7 (RCA smoked glass VT-231's) and Genelex Golden Lion 300B's; Onkyo C-55VL for CD's & SACD's; Sansui TU-919 for FM; iPod and iPhone for mp3. Ohm Walsh 5000’s in Bubinga with braided 8 strand Monster Cable (Litzendraht design) wire. All connecting cables shielded Monster Cable, gold RCA plugs. All common power (except amp) plugged into Tripp-Lite isobar ultra.

Associated gear
Ohm Walsh 5000
Hi Carja,

Any follow up comments after a few months? Still not many reviews out there. And, do you know, or does the manual specify, the input impedance?

carja, your response to your '250 is about the same as mine to my '750s....'musical and muscular' indeed. What the '750s have is a sense of ease...effortlessness...that I had not heard before. Here's my story about my '750s.

I'm glad you love your '250.

Zekreb, the input impedance is not on McC's site; I've asked c-j's Ed Deitemeier and will post it as soon as he tells me.
Thanks Jeffreybehr. I've corresponded with Ed about CJ stuff, didn't realize they were handling McCormack as well, though I knew CJ bought them.

100K ohms is plenty - good to hear.

My leading contender for an amp has been the CJ 2500A, but they don't show up for sale too often. The DNA-250 looks like a good alternative. I would want to keep the smooth, slightly warm midrange and gentle highs that the CJ SS amps have a rep for. Either of you have any experience from which to make a comparison? It seems like the McCormack might have the advantage with microdynamics given the DNA design.
Just read your thread Jeffreybehr. With your mods and 750 monos vs. 250 stereo, I'm not sure I can rely on your impressions for my decision though!
In general, from my experience, the original DNA .5, 1 and 2 were good souonding amps. The Mccormack mods to rev A status transformed them into great amps. Exceptional even.

The 150, 250, etc amps incorporated much of the Rev B mods, and as such they were amazing amps, but there was still more to be had from them so Steve again offered upgrades to make them world class.

The DNA 500 and 750 amps incorporated much of this into extremely high powered packages capable of driving anything. There's not much to be upgraded on these, but you can always parts swap for more boutique components, getting more subtle micro details and micro dynamics out of them.

I think if you have the opportunity to pick up a used, Rev A modded amp from any DNA series you will be set for life. If not, then stepping up and paying Steve to perform these mods on a standard unit is less cost effective, but still will turn what you have into something you will never want to sell.

Thanks for your reply. Do you know the ballpark cost for doing the upgrade to a Rev.A? Likely varies by model. There is a DNA-750 Deluxe available, for example.

My understanding is that Steve M. was out of the loop with the current DNA-250. Has the DNA technology, but with CJ taking it from there. Do you know something different?

I'm sorry, I meant DNA-2 Deluxe (I think I typed DNA-750 - waiting for post to moderated).
Zekeb,Im quite sure you are correct, I dont think Steve M had anything to do with the 250. The 225 ,yes.Go to the McCormack web site for prices on the mods. I know he doesnt offer one for the 250.
Sorry guys for the late response- after several months I gave up for a reply! I am still very pleased with the 250. There is still a small amount of background hum that was not present with the Sumo, but one can't detect it even on quiet passages of classical pieces, so I ignore it. I still think that it is some sort of ground loop issue, not worth pursuing, and it's not the amp's fault.

One really couldn't ask for more in a SS amp- no distortion, no coloration of the sound, excellent sound stage. You can crank up the preamp to full bore (without a signal of course) and not hear any background noise except as I mentioned the barely audible ground loop. Since it's not amplified by turning up the preamp, that means that it is after that stage. This amp barely gets warm, so it not only has good heat sinks, it's just loafing along.

McCormack himself designed the 225 but not the 250. The folks at CJ are no slouches, of course, so I think that they just made a few minor modifications to the 225 design to "upgrade" it. BTW, the offers upgrades on DNA1 and DNA0.5

Here's an interview with Steve from last year:

His website lists his ultimate design for a preamp, the VRE-1 Since it's $17K it's out of my affordability. There is also an interesting product called the Interocitor, which apparently is for grounding issues and can use either balanced or unbalanced inputs and/or outputs. Might be interesting for me to see if I can eliminate that barely audible hum in my system, but for $1800 I think that I'll wait for a review. Or maybe I'll drop him an email and see what he thinks. He doesn't live far from me.

Of course, he also offers many upgrade options on all the equipment that he originally designed, up to the DNA 225 but not the 250. I have no idea if some, all, of none of the modifications are audible, though I'm sure that on instrument testing they are all improvements in performance. I'd have to ask my son, after he gets his electrical engineering degree for advice, but it's a moot point as something tells me that Steve wouldn't touch something that he didn't design.