- Feb 21, 2007
Some of you may have read my earlier review of the Hot Audio DAC Extasy. I enjoyed that little USB DAC so much that I decided to pick up the next model in the lineup (and current flagship), the DAC WOW. The WOW is available in several variants: a USB only model, an SPDIF only model with a toslink connector, and a combination model with both USB and toslink inputs. I opted for the SPDIF model since I intended on using it as a simple upgrade to an older CD player. This model sells for $159.99 direct from www.HotAudio.com and as usual comes with the 30 day money back guarantee if you don't like it.
In my review of the Extasy, I talked a bit about the history and design principals of Hot Audio. I’m going to build on that rather than repeat it, so please read the Extasy review if you want that information. This time around, I asked Dave (who essentially IS Hot Audio) a bit more about why he feels his DACs are special. To paraphrase his response:
1) All PCB layouts are done by hand and not by PC.... He thinks very hard and long before laying a track down as to where it goes, what kind of signal is going to be passed through it, how it might affect other signals, and how he can get one connection to another connection with the minimum of noise and the maximum of signal integrity.
2) He has tried and settled on what he considers to be a better sounding solder medium.
He has tried several solders, even of the same type but by different manufactures to find the sweetest sounding solder. He also believes that by hand soldering connections, you get a superior, warmer sound then by conventional SMT ovens.
3) All components are continually A/B tested against previously used options, looking for areas of improvement. Dave is constantly revising his designs whenever he finds a component that makes even a small improvement. These unannounced improvements are easily possible when you hand make each component yourself.
4) Each DAC is hand made and he listens to them one at a time for several hours each. He contrasts this with DACs made on an assembly line, where it is only realistic to do quality assurance tests on random samples, with little to no actual listening time involved.
5) Finally, Dave advised that he would prefer to be thought of as an "artist". Not an engineer who produces gear on an assembly line, but instead hand crafts each unit with special attention to detail and care. Knowing that I have many higher ends DACs at my disposal, he invited me to compare the DAC WOW to other DACs to see how it holds up. It sounds to me like he is very confident and proud of the creations he has made.
The DAC WOW is similar in many ways to the earlier Extasy. Externally, the aluminum case is identical, with the same rugged feel. Obvious differences are a toslink port instead of a USB port, gold RCA connections instead of silver, and of course a small plug for connecting the power supply. The USB version draws power from the USB bus, so I believe this is the only model that needs external power. Other than that we find the same pair of red LED lights to indicate power signal lock.
When we open the case, again things are similar to the Extasy but with a few changes. We find the same Burr Brown DIR9001 digital audio receiver, which sends the signal straight to the Wolfson WM8524 DAC chip. All capacitors are Nichicon FW series, and it appears to have the same oscillator chip for a system clock.
The Wolfson WM8524 is an interesting chip. Apparently it is a step up from the WM8501 used in the Extasy. Like the WM8501, it has a built in line driver with filtering, so no extra output stage is needed. Wolfson also states that it “features ground-referenced outputs and the use of a DC servo to eliminate the need for line driving coupling capacitors”. Coupling capacitors can have a huge influence on the overall sound, and by using this particular DAC chip the DAC WOW is able to bypass that potential problem area. I’m not saying that any design with coupling capacitors is bad; what I am saying is that all budget priced gear has to make sacrifices somewhere, and this is one less place where the DAC WOW might have to do so.
I had never heard of the WM8524, so I did a bit of searching to see if it has been used in any other components. Interestingly, I only found two other DACs that feature this chip, and they are on very opposite ends of the market. The first is the Mute Audio GrubDAC, which is a very small DIY design using roughly $50 worth of parts. The other is the Unico CD Primo from Unison Research, a high end CD player selling for over $2000. Both products seem well regarded within their respective categories. Of course, there is much more to the sound of a product than simply what DAC chip is used, so I mention this as just a general item of interest.
This particular DAC WOW configuration accepts up to 24-bit/96kHz signals via the toslink input. The USB version is limited to 16-bit/48kHz, and I assume the dual input version handles those same rates on those same respective inputs. The fact that my version handles high resolution audio was very convenient. Much of my hi-res library is in the form of downloads from Linn, HD Tracks, etc, and I often burn them as 24/96 digital audio discs. These DVDs can be played on almost any DVD player, making hi-res music accessible for a reasonable price.
Note that the mark above the power socket is just glare from the flash. The slight marks to the right of that are indeed minor scuffs, which is how the unit arrived. This is an indicator of their hand built and pre-tested nature, and it didn't bother me.
Since the WOW uses the same enclosure as the Extasy, the build quality basically the same. The cutout for the toslink port has some rough edges, which again reminds you that this is a hand built product. It actually feels slightly lighter than the Extasy, probably because the design requires fewer capacitors. The screws go in flush and everything feels solid and well done.
Just like the Extasy, the WOW arrived in about a week (from Canada to California). The simple package included the DAC itself and the wall wart style power supply. Everything was protected by bubble wrap material. There is no manual included, and frankly I don’t think there needs to be. Hot Audio returns emails very promptly, and the devices are so simple that there really is no need for anything else.
I tested the DAC WOW with an assortment of optical disc players to see if it was superior to their internal DACs. The players included a Toshiba HD-A3, a Samsung BD-P1200, a Theta Miles, a Lexicon RT-20, and a Rotel RDV-1092. I paired the DAC WOW with various headphone amps including the Matrix M-Stage, Maverick Audio TubeMagic A1, Darkvoice 337SE, and Eddie Current ECSS. Headphones used were the JVC RX-700, Equation RP-21, LiveWires Trips, Kenwood KH-K1000, Grado RS-1, and the Unique Melody Miracle. Comparisons were done with other DACs including the Hot Audio DAC Extasy, Audinst HUD-mx1, HRT Music Streamer+, Sigtone Shek D1, and the Matrix Cube.
I burned in the DAC WOW for about 150 hours before listening to it. Cables were Impact Acoustics SonicWave, Ethereal, and Blue Jeans. I listened to a good mix of 16/44.1 and 24/96 material.
I’ve decided to start putting this on all my reviews. I feel the need to point out (even though it is obvious) that this is merely my opinion, based on my experiences with this product. It should not be taken as objective fact. I’m not perfect, and I’m not being paid to do this. I’m just a guy who likes music and likes to try new gear. I try my best to be fair and objective, to point out the good and the bad, and to compare to a wide range of products. I also generally hold things to a standard dictated by the price. So for example, if I say $200 “Amp A” has excellent bass, and in a different review say $1200 “Amp B” is not particularly impressive in that category, I don’t necessarily mean that Amp A has better bass than Amp B. Whenever relevant, I will make direct comparisons.
The DAC WOW is advertised by Dave from Hot Audio as his best DAC yet and current flagship model. Keeping in mind that this is still a budget product, it does sound good enough to warrant that type of enthusiasm from him. I found it to be fairly transparent and mostly neutral, being just slightly tipped towards the warmer side of the spectrum. As much as I liked the DAC Extasy, I found the DAC WOW to be even better, although I’ll discuss more on that topic later.
Listening to a wide variety of music, I noticed that the WOW allowed a fairly clear window into the performance, no matter what the genre. Drums were full bodied, cello and violin had a rich texture, and vocals were nothing short of believable. One of my standard tests for new gear is the track “Tricotism” by Ernie Watts, from the excellent XRCD release of his album “Unity”. Towards the beginning of the song, we hear both an electric bass and an acoustic bass in a sort of joint solo that last for a while. For me, the mark of good playback equipment is when it allows me to clearly follow either of the two instruments. Lesser gear makes them seem blurred together and hard to pick apart. Since I paired it with much higher end gear, the DAC WOW was potentially the weak link in the chain. I’m happy to report that it passed this test with flying colors. Another test comes from Michael Jackson of all people, with his classic track “Rock with You”. At about the 2 minute mark there appears a finger snap sound at half note intervals, hard panned to the left side. For me, this works in the opposite way of the Ernie Watts track in that it sticks out way too much unless good equipment is used. With lesser gear the snap is unnatural and distracting. With the DAC WOW in my system it still has the proper bite to it but remains integrated smoothly within the flow of the music.
These are just a few of many examples where the DAC WOW turned in a solid performance for its price point. I especially liked how natural it sounded with 24/96 tracks. I tried many 24/96 encoded discs, and although I’m unclear if it is the increased resolution or just a better recording//mixing/mastering process responsible for the great sound, I can confidently state that they sound excellent. While falling short of true reference quality, the DAC WOW does get you part of the way there and at a very reasonable price too.
I like the choice that was made to give the DAC a slightly warm characteristic. Opinions differ, but I prefer this signature to that of the Cambridge Audio DacMagic (for example) that tends to focus a bit more on the top end. Obviously this is a personal preference and you have to decide for yourself what you like.
Weak points? There are surprisingly few, especially for the price. Nothing really stands out as a specific weakness, although of course there are areas where other DACs outperform this one. For example: I feel that some of my reference DACs (costing many times the price of this little DAC) open up the soundstage even more, and allow for more layering and harmony between the instruments. I wouldn’t call this a specific weakness though, as the DAC WOW performs admirably in all of these areas, just not as well as the big dogs.
Hot Audio DAC Extasy
The DAC WOW offers a decent step up from the former flagship Extasy in terms of resolution and detail. They both fall on the warmer side of the spectrum, with the Extasy going several steps further in that regard. One improvement comes when listening to well recorded cymbals; the WOW makes it more believable that someone is striking an actual cymbal within earshot, rather than sounding like a recording of same. It doesn’t seem that there is much increase in actual high frequency extension per se, and in absolute terms it still falls short of reference caliber, but what is there is more pleasing and real than the Extasy.
Since the WOW matches or exceeds the Extasy in every category, so it must be the better choice, right? Oddly enough, I don’t entirely feel that way. While I personally prefer the WOW in my particular application, some people may actually benefit more from the more forgiving nature and added warmth of the Extasy. The WOW is considerably more revealing, and if what is being revealed is the shortcomings of your amp or headphones, then that might not be welcome. The Extasy might be just the thing for someone who has a budget setup (Sennheiser HD555, Grado SR80, Goldring DR150, Equation RP21, etc.) that they are pleased with and aren’t planning on upgrading soon. The WOW is the better choice for anyone aspiring to the bigger leagues (HD600, Grado SR325, AKG K701, etc.) as it will help maximize enjoyment of a highly resolving setup.
HRT Music Streamer+
I feel bad because the Music Streamer+ is a nice little DAC, and I’m constantly beating it up in comparisons. Nevertheless, the DAC WOW handily beats this last generation HRT offering with improved dynamics, more detail, and an overall better balance. As I discovered when I compared it to the Extasy, the HRT is slightly thin in the lower region, and although the WOW has more subdued lows than the Extasy it still comes across as sounding more full and complete than the HRT. Since my model is toslink only, it isn’t specifically a competitor for the USB only HRT products. I’m making the assumption here that the DAC WOW USB and combo versions retain the same sonic flavor as my model, and as such anyone needing a simple USB DAC should strongly consider the Hot Audio offerings. Unfortunately I have not had a chance to hear the new HRT Music Streamer II models, so I can’t comment on those.
Sigtone Shek D1
When I compared the Shek D1 to the DAC Extasy, I commented on how the Extasy was slightly superior overall, but couldn’t match a certain “naturalness” of tone that the D1 had. However hard to describe, that same naturalness is even better with the DAC WOW. Again I return to those realistic sounding cymbal strikes, as well as female vocals which can at times cause lesser equipment to stumble. The WOW handles all of these with remarkable ease. Still, the D1 has an appealing sound signature that remains enjoyable despite being somewhat outclassed, and I can see how these 2 devices could easily coexist in my house.
The Audinst has been my standard in the budget DAC category for a while. It is balanced, neutral, and fairly transparent sounding, all for a great low price. The DAC Extasy came close but couldn’t quite match it, instead offering more of a warm and smooth signature. The DAC WOW is very similar sounding to the Audinst; so much so that I had difficulty telling them apart at first. Now that I’ve spent a lot of time with them, I feel I sort of have a handle on it, but they are still very close.
What it comes down to is this: With very well recorded music (often 24/96 material but not exclusively), the DAC WOW seems to have an edge in its ability to retain tonal accuracy during complex musical passages. This manifests most often in large scale orchestral pieces (Rachmaninov, Dvorak, etc), more complex jazz (think Hiromi rather than Miles), and technical metal (Becoming the Archetype, Meshuggah, etc.) The Hot Audio offering, when paired with high end gear, seems to have a higher threshold before being overwhelmed and becoming the weak link. Aside from that, there seems to be a very slight richness to the sub bass frequencies that is lacking with the Audinst. It is not a big difference though, and I didn’t really pinpoint it until I got the Unique Melody Miracles with their amazing sub bass performance.
At the end of the day, both of these products are very nice sounding, and both have something to offer. The Audinst is more versatile with its built in amp, USB to toslink transcoding, and 24/96 input over USB. But for pure sound quality, the DAC WOW has the edge, and is my new number one recommendation for a DAC in this price range (assuming you can live without any bells and whistles). That being said, if someone already owned the Audinst, I would say don’t bother “upgrading” to the WOW as it is a fairly incremental improvement.
The Cube is significantly more expensive at nearly twice the price of my DAC WOW configuration. That extra money buys you quite a bit more functionality as well as just slightly better sound. Based purely on sound the two are nearly as close as the prior Audinst/WOW comparison, but this time the Cube comes out ahead.
The Cube has a bit more of a three dimensional soundstage, and seems to have better control of the transients as well. This is possibly due to the fact that the Cube has a more robust power supply, whereas the WOW uses a simple wall wart. When I disable the upsampling feature of the Cube, the soundstage becomes more intimate and it sounds even more similar to the WOW, to the point where I doubt I could reliably tell them apart in a blind test. As I mentioned in my review of the Cube, it is an excellent sounding product, so putting the WOW in the same league is a big compliment.
I paired the DAC WOW with multiple CD players to see how it stacked up against their internal DACs. As expected, it was not quite able to keep up with my expensive Rotel, Lexicon, or Theta players. The surprising part was just how close it came though; especially with the Theta player. Yes, this player is over 10 years old, but it did sell for over $2k new, and is still what I would consider a high end device. But the DAC WOW gave up very little when directly comparing the two. The main areas where the Theta excelled were deep bass reproduction and smoothness on the top end. But again, the difference was small which is very impressive.
Some lower priced players I tried did not fare as well. I love the sound made by the Samsung BD-P1200, and the Toshiba HD-A30 is pretty good as well, but the DAC WOW beats them both. Even the good old Marantz CD63SE shows some improvement when paired to this little Hot Audio box. I truly see this as a quick and simple upgrade for someone who owns a classic player, likes the look and user experience, but wants a bit more performance from it. I highly doubt you could replicate this type of sound by moving to another player for $160.
The DAC WOW is not a fancy box. It is small, unobtrusive, and rugged, which is the perfect recipe for a device that will possibly spend its life hiding behind a transport. The sound is clear and detailed, with excellent response from top to bottom. It gives up very little compared to some more expensive units out there.
Looking inside the case, it is deceptively simple, but I actually think that is where its strength lies. If it didn’t have a charge pump and line driver integrated into the Wolfson WM8524 chip, it would require separate coupling capacitors and an I/V stage that would almost surely be compromised at this price point. As it is, we are able to hear the signal as it comes directly off the DAC chip, and it sounds excellent. I have no doubts that this exact DAC could be stuffed into a large fancy case and sold at double the price (or more) and nobody would bat an eyelash. The fact that the same DAC chip is used in the expensive Unison Research player indicates that it has lots of potential, and I think this simple DAC design allows that to shine through. As I mentioned before, this is my new top recommendation in this price range.
The excellent Burr Brown DIR9001 digital receiver goes straight to the Wolfson WM8824 DAC
The DAC WOW in its natural habitat: jammed behind a CD player on my shelf, amidst a mass of tangled cables. Good thing the case is rugged!