SMc AUDIO DAC-2 GT-24
SMc Audio DAC-2 GT-24 Reviews
6moons – SMc Audio – McCormack UltraDac, by Francis Baumli
Secrets of Home Theater and High Fidelity – McCormack Audio Digital Drive SST-1 and DAC-1, by John E. Johnson Jr., Editor-in-Chief, 1995
Conrad Johnson Owners – McCormack DAC-1, by eagle6014, 2015
Audio Asylum – McCormack DAC-1 by Ecruz, 2004
SMc Audio DAC-2 GT-24
SMc Audio is Steve McCormack and his associate Patrick Jeter, and my relationship with them goes back around 20 years, first as a tire-kicker, then as a client, and finally as a friend, which says a lot about how they work with all of their clients. I will call their customers “clients” because SMc Audio doesn’t simply sell stuff to people, but rather they work together with audio enthusiasts to understand their systems, sonic and musical preferences, and goals, and only then do they discuss which product or upgrade, and what level of upgrade, would fit best to meet the client’s goals and budget. Through this process, and especially if you go through it two or three times with them, it is hard not to call them friends since it is not only a pleasure to work with them on specific projects, but also a pleasure to simply talk with them and learn from their wealth of audio knowledge, hear about new upgrade paths, and share ideas.
My first McCormack product was an old DNA-2 amplifier. A behemoth designed by Dave Reich of Theta fame. The balanced input didn’t work and even though I purchased it used, when I called SMc, Steve took the time to talk me through troubleshooting options and was upfront about what was probably wrong with the balanced inputs – a known issue. It turned out the solution was to simply use the single-ended inputs.
Later, after selling that DNA-2, I became intrigued by the many positive testimonials from people who had their original McCormack Audio gear upgraded by SMc Audio. It seems the original McCormack Audio equipment mostly utilized thoughtful, functional, and effective design choices and, at least the amplification gear, was mostly limited in performance only by cost choices necessary to achieve desired price points.
My first upgrade performed by SMc Audio was about 12 years ago when I sent them a McCormack TLC-1 (Transparent Line Control) preamp that Steve and Patrick then turned into something very special, and very close sounding to Steve’s extremely well-regarded (basically world-class) VRE-1 (Virtual Reality Engine) preamp, which is now in its VRE-1C iteration. The VRE-1 was introduced around 2008, not long before I had my preamp upgrade preformed, so Steve was able to use the knowledge and design choices resulting from years of perfecting his preamp vision, in crafting the upgrades that he used in my TLC-1 Signature Edition preamp. The upgraded TLC-1 sounds fantastic and, speaking of value, it has been in my system for the past 12 years with nothing I have tried even coming close to making me want to replace it.
Steve and his original McCormack Audio company are best known for amplification products, so I next had them upgrade a DNA-2 amplifier and following that they built me a pair of monoblocks based on the McCormack DNA-1 amplifier platform. Pictures of those mono amps, along with a picture of my preamp, are shown on the SMc Audio website homepage. All I can say is that I happily replaced the amplifiers I owned at the time, and that sold for $17K (Clayton M300) and currently sell for $34K retail (Lamm M1.2 Reference), with those SMc Ultra G monoblocks, and I haven’t once regretted the decision. To my ears, all of the SMc Audio gear I have heard has an organic musicality that would cost stupid money to equal.
The SMc AUDIO DAC-2 GT-24 began life as a McCormack DAC-1, which was first introduced in the heyday of McCormack Audio, sometime in the mid-1990s. There is not a single review of the SMc Audio DAC-1 GT-24, so I have posted a few reviews and write-ups of the original (non-upgraded) McCormack DAC-1, as well as a 6moons review of the very first upgraded DAC-1, called the SMc Audio UltraDac. If you read the reviews, the original DAC-1 was quite well-regarded, with reviewer John Johnson stating in 1995:
“The SST-1, DAC-1, and Wonder Link cable, when used as a package, resulted in some of the most breathtaking CD sound we have ever heard. The upper registers were crisp, but without harshness of any kind. Steel string guitars are a good test for this, and the McCormack blazed through unscathed. Our planar-magnetic speakers just sang. The deep end was - well - as deep and tight as any we have heard, and better than most.”
Audio Asylum poster Ecruz posted this in 2004 about a used DAC-1 he purchased:
“when I threw the DAC 1 in to the mix, HOLY SMOKES! I don’t have to skill to describe in words how much better it sounded. It sounded like I bought a new cd player. Everything improved. The soundstage got bigger. The upper frequencies more extended AND less harsh. The low end more extended AND tighter. A much warmer, richer and more realistic sound. Dare I say, tubelike.”
I included the Conrad Johnson Owner’s forum post because the thread includes a few nice pictures of the original McCormack DAC-1, including a shot of the insides. CJO forum poster eagle6014 said this in 2015:
“As far as comparing this to other dac’s I’ve had, it sounds great. No complaints here, classic dac sound for my huge 80’s collection.”
The 2009 review written by Francis Baumli about the SMc Audio UltraDac, and posted on 6moons, was incredibly positive about the sound of the upgraded DAC-1 and, along with my positive experiences with SMc Audio, was the reason I wanted to try their upgraded DAC. The pictures in the 6moons article indicated changes from the original DAC-1 in the power supply and output, but not too much with the conversion board. Baumli enthused over how good the UltraDac upgrade sounded to him, concluding the review with, “the SMc Audio Ultra DAC-1 is…better than any of the current competition.” In the words of Ned Pepper to Rooster Cogburn, “bold talk”.
A year or two ago, I was able to pick up an old McCormack DAC-1 for cheap and had it shipped directly to SMc Audio. I certainly didn’t need another DAC and told them I was in no hurry for the upgrade but I was curious so I told them to “go ahead with the project when you have the time.” I was actually surprised when earlier this year I received a call from Patrick who said, “your DAC-2 GT-24 is finished.” He added, “I know it has been a while so if you no longer want it, we have other customers who would.” I told Patrick that I absolutely wanted it so “send it on over,” and I am glad that I did.
The first thing I noticed is, wow, this thing weighs a ton! I was surprised to find they had used the gravity base that they used on my monoblocks, which is essentially a thick brass bottom plate that covers the entire bottom of the chassis and directly attaches to key components. The gravity base seems to give the sound “gravity” – just kidding, sort of. I suspect, but of course cannot prove, that anchoring and mechanically grounding key components and boards to the heavy brass base imparts additional solidity and possibly the desirable acoustic attributes of brass.
The second thing I noticed was the nice-looking appearance of the DAC-2 GT-24. Like all of the gear SMc Audio has upgraded for me, I asked for an upgraded faceplate with the SMc logo and I was not disappointed with the result. Finally, the name DAC-2 GT-24 is not the same as the “UltraDac” from the 6moons review, so I figured something must be different.
When I looked at the pictures that Patrick sent to me of the insides of my DAC-2 GT-24, that are available to look at on my virtual system page, there seemed to be a whole lot more going on than what I expected from the pictures that were included in the 6moons review of the UltraDac. That is sort of par for the course when working with SMc Audio over the years. They continue to innovate and incorporate the new improvements they discover as they upgrade their client’s gear. In the pictures of my new DAC, I saw some cool stuff like a magnetic breaker on/off switch, a new white circuit board for the power supply, Jupiter copper foil capacitors, a large oil capacitor, Lundahl output transformers, a clean-looking layout, and nice-looking soldering work. The DAC-2 uses the same Crystal Semiconductor CS8412 "E" Version receiver and CS4328 DAC chip from the original DAC-1.
Operationally, the DAC-2 inputs through either S/PDIF coax or Toslink optical. No USB or AES/EBU. I have tried both inputs and based on my listening, the coax input is sonically superior but the Toslink input still sounds good. Both single-ended and balanced outputs are provided and the connectors are first rate from Furutech. The DAC chip only supports 18 bits and sampling rates up to 48kHz so adjustments were needed in Roon to avoid glitches with tracks having higher sampling rates.
When I first listened to the DAC-2 GT-24 I had the impression that music played through it sounded “alive”. I also perceived a natural, organic tonal quality similar to the Mojo Audio DACs, and smoothness similar to the Merason. This is an 8x oversampling Delta-Sigma DAC so, while operationally it is one of the more common DAC designs, it is different from the other DACs in my current comparisons. The Delta-Sigma DAC chip is probably closest to the Merason that uses a Delta-Sigma hybrid BB PCM1794A chip, and the Benchmark with its ESS Sabre ES9028PRO chip. The other three in the comparison are R-2R type DACs using chips by Analog Devices, an AD1865 in the LTA Aero and dual AD1862N chips in the Mojo DACs.
To quote Benjamin Zwickel of Mojo Audio,
“Delta-Sigma DACs, which comprise over 95% of the DAC chips sold today, do not actually “decode” the bit stream but rather "interpolate" it. They take in the digital bit stream faster than the music is playing, analyze it, noise shape it, error correct it, interpolate what they think the musical signal was supposed to look like, and then output a flawless waveform. Not quite the waveform which was quantized, but a very smooth and very even waveform. That is why Delta-Sigma DACs sound so smooth and refined. This is also why Delta-Sigma DACs have an advantage when playing mediocre sources such as music streamed from the internet.”
As I read up on the old Crystal Semiconductor CS4328 chip used in the DAC-2, I learned it was considered a pretty good chip for its time and capable of converting digital into a good-sounding analog output. The specifications list the chip as having 18-bit resolution and a maximum 48 KHz sampling rate. It performs 8x oversampling digital interpolation followed by 64x oversampling, one-bit, delta-sigma modulation. It really is a vintage piece, but does that really matter? CDs are standardized at 16bit resolution and 44.1kHz sampling rate and most of what we listen to is essentially CD quality.
As I ran through my test tracks, I kept thinking that I could happily live with the SMc DAC-2 GT-24. The tonal qualities were clear and natural sounding, reminiscent of what I remember from really good CD players. The sound was smooth in that there were no shrillness, roughness, or other undesirable digital sounding artifacts. At the same time, the DAC-2 was granular enough to capture the distinct texture of different vocalists, including breathiness, grittiness and raspiness as those qualities are present. Examples that were easily distinguishable through the DAC-2 included the intimate breathy quality of Dominique Fils-Amie’s vocals on Birds, Susan Tedeschi’s trademark rasp on Angel from Montgomery, and Warren Haynes signature growl on Gov’t Mule’s Thorazine Shuffle.
Bass is solid through the DAC-2 and underpins the upper frequencies without getting in the way. The mids and high frequencies are appropriately proportioned and the entire presentation seems even-handed. If pressed, I would say the DAC-2 leans just a smidge to the sharper side of the curve and is perhaps just a touch lighter on its feet than I am used to with the Mojo Audio EVO Pro, or certainly with the Merason DAC1 MkII that has a sort of creamy lower midrange/upper bass warmth. However, I do not consider the result to be irritatingly detailed, or too focused on attack/leading edge, as I have heard with some equipment. I suspect this presentation from the SMc DAC-2 GT-24 I have described would likely hit the sweet spot for many audiophiles. Sound staging is similarly even-handed, with enough dimension to portray a realistic image of the positioning of singers and instrumentalists, but not so much as to seem overblown.
Considering this is a DAC that most of you will never hear (I understand there are only 12 of them currently), I will stop the descriptions here, and conclude by saying that what Steve and Patrick have crafted is amazing considering their starting point with the older conversion technology. However, they are so good with power supplies, amplification, and output stages I am not really surprised that they were able to make this DAC sound great. The tonal qualities, texture, and natural sound from the SMc DAC-2 GT-24 make it certainly one of the more enjoyable DACs in this comparison, and one that I could happily live with in my main system.
As a last thought, it has been my privilege to work with Steve and Patrick over the years. My trust in them to create great sounding audio gear that has brought me joy has been justified by their great work. Their many satisfied clients have benefitted from their passion for audio, commitment to continuing innovation and improvement, attention to detail, and unwavering concern for client satisfaction. Thank you, Steve and Patrick.
