Emotiva Stealth DC-1 DAC/Preamp Review

Emotiva Stealth DC-1 Introduction

DACs are these things that show up on spec sheets for most people. They are like the ingredients on a Twinkie - strange letters that don't really spell a word that can be recognized by the typical human. The inherent function of a DAC is explained when you explode the acronym - Digital to Analog Converter. The DAC is the chips in your device (albeit a portable player or phone all the way up to AV receivers and standalone units) that take the ones and zeros of your digital content and transforms it into something that can be amplified and played back by your speakers or headphones.

I like the "QTY 1" on there

While DACs are a pretty mature technology, there are still a lot of devices out there that, frankly, sport pretty substandard DACs. Your phone, your computer, budget receivers and other electronics, and more all try to save money by using outdated or inferior DACs. If manufacturers are trying to hit a price point and they know the majority of people aren't going to care about the DACs, they'll skimp.

But you aren't the majority of people, are you?

Another device you might not be familiar with is a headphone amp. Like an amplifier for a speaker, a headphone amp is used between your source and your speaker (in this case a set of headphones). There are a number of reasons you might need a headphone amp. The most likely is that you bought a pair of headphones that are particularly hard to drive and you can't get the volume out of them you want. But there are other reasons including taking the load off your device to save battery life, to connect directly to an analog source, and more.

Emotiva has taken both of these devices and put them into one enclosure. Welcome to the Emotiva Stealth DC-1 DAC and headphone amplifier. 

First Impressions

Like all Emotiva products, the Stealth DC-1 came well-packaged, this one in a layer of foam. It was double boxed for protection and was encased in a canvas bag for reasons only audiophiles truly understand. It came with a power cord, a remote, a USB cable, a manual, and a little screwdriver.

Yes, a screwdriver. We'll come back to that.

I was impressed immediately with the form factor of the Stealth DC-1. It is small, for sure, but it is heavier than I expected. There are vents on the top and it is clearly packed with technology as you can see the power supply through the vents. The bottom has four inverted pyramidal feet and more vents. There is a switch to set the correct voltage. There is a large label down there as well.

Look at that sexy beast!

The front has two knobs, two headphone ports, and a two-line display with Emotiva's iconic blue backlighting. The left knob controls input selection and menu access. Turning the knob will flip between the inputs while pressing the knob accesses the menu. Additional presses drills down or selects while turning the knob alternates between the choices. The right knob controls volume while pressing on that knob will power switch the Stealth DC-1 into and out of mute if it is on and out of Standby mode if the unit is powered down.

The back is where the Emotiva Stealth DC-1 gets really interesting. With a DAC you expect some sort of digital input. Many will have nothing more than a USB input and a headphone output. The Stealth DC-1 has a full suite of digital inputs including USB, coaxial, optical, BNC, and AES/EUB (one each). If you haven't heard of those last two, you're living on the wrong continent as they are digital connections used elsewhere. Don't worry, many people will be happy to see them. There is also a single analog input (unbalanced RCA), which is obviously intended for pass-through to your headphones or external amp.

Real estate is at a premium on the back of the Stealth DC-1

That's right, the Stealth DC-1 can be used as a two-channel preamp for a (mostly) digital system. It has not only RCA unbalanced connections but XLR balanced connections to your amps. This takes the Emotiva Stealth DC-1 into a whole new realm of usefulness. The Stealth DC-1 retails for just under $500. This price is very competitive for a high quality headphone amp and DAC, let alone adding full preamp. Honestly, I can't even wrap my head around how much you get for your $500. For the first time, I can't come up for a reason NOT to own a Stealth DC-1. And we really haven't started this review yet. Mind=Blown.

Connections you won't find on many other DAC/headphone amps

Stealth DC-1 DAC Build Quality and Functions

It is clear that that Emotiva had both audiophiles and professionals in mind when they built the Stealth DC-1. The chassis is constructed out of solid steel and is hefty and inert. It is a half rack width and one unit tall for those that rack-mount such things, but it is small enough to throw in a bag for easy transport for those that take such things with them. These people are not just professions that need a high quality DAC on the go but those headphone enthusiasts that must have the best sound wherever they are.

Its exceptionally small size means you can put it in your office without taking up much space. While it is hefty for its size, it isn't so unwieldy that placement becomes a problem. From Emotiva: "The small size makes it easy to place the Stealth DC-1 in a rack, in a carry case, or even on top of a computer or console." The industrial looks may turn off the Apple crowd but I love the way it looks, it small and boxy with an easy to read blue display. Just picking up the Emotiva Stealth DC-1 conveys quality. The connections on the back are all of the highest quality and the knobs on the front feel absolutely rock solid and unbreakable (didn't test this and you can't make me). While not everyone will agree with me about the looks, I like it and I think many (especially those that have owned Emotiva gear in the past) will agree

The bag helps keep the audiophile fairies inside

The DAC

The main focus of the Emotiva Stealth DC-1 is the DAC. If it had a primary duty, it is to provide the highest quality digital to analog conversion as possible. If you ever wondered if the DACs in your system were good enough, this would give you the definitive answer.

Pictured: All the digital connections you could ever need

The Stealth DC-1 is called a "Reference-quality differential DAC" by Emotiva for a reason. The big concern with DACs is jitter. All digital music is encoded or recorded at a specific sample rate. If it is a CD, it is 44.1kHz but other high definition sources can support different sample rates. Think of the sample rate as a clock or a metronome - it tells the DAC how to decode the ones and zeros so that the music is playing at the right speed (simplified, but this is basically how it works). The extent that the DAC and the original recording or encoding are different in their timing is jitter. Low levels of jitter may be hardly noticeable. High levels can sound like a record with its hole punched off center.

Basically - Jitter is bad. Getting rid of it is good.

We can't get rid of all the jitter on our end. If the jitter was introduced at the A/D conversion point (analog to digital - i.e. when it was recorded), then there is nothing you can do. But with high quality recordings, jitter during playback can be solved.

There are only four feet on the bottom because five feet makes no sense

The Emotiva Stealth DC-1 uses "...dual independent AD1955 differential D/A converters, each operated in their highest quality internal differential monaural mode, for the lowest possible noise and distortion, followed by professional-grade LM4562 op-amps in the analog section for maximum fidelity." See, the Stealth DC-1 wasn't really designed for just the audio enthusiast. The Stealth DC-1 was designed with what we like to call the "prosumer" in mind. This is a product that will appeal to not only consumers but also the pros out there that are looking for high quality DACs for use in professional recording applications.

The Steal DC-1 has both synchronous and asynchronous sample rate converters (selectable). The difference between the two is simple - in synchronous mode, the source clock is used, in asynchronous, the Stealth DC-1 clock is used. Now, many devices claim asynchronous sample rate converters but what they really provide is asynchronous on the USB input and synchronous on everything else. The Stealth DC-1 provides asynchronous sample rate conversion on all digital inputs for the best possible jitter reduction regardless of input.

The least polished parts of the Stealth DC-1 were stickers on the bottom label that were pulling away even before I opened the box

The Headphone Amp

The Stealth DC-1 has dual headphone outputs on the front of the unit. These are both 3.5mm ports, which is probably the only thing about the Stealth DC-1 that had me squinting my eyes in confusion. Two 3.5mm ports? Not two 1/4" ports or one of each type? Really? Hmm. Interesting choice. 

My guess after looking inside the Stealth DC-1 was the choice was made as a space-saving measure. What? Did you forget about the screwdriver? We're getting there.

Just look at it! SEXY!

The Stealth DC-1 has two Muses 72320 precision volume control ICs operated in dual gain control mode. This allows you to have two different headphones with different impedances connected at the same time. The volume control adjusts in .25 dB steps from -100dB to +12dB which takes FOREVER so scroll through. With most headphones, reasonable listening volumes happened between -30dB to -25dB. The fine resolution was nice to see however.

I am the main headphone reviewer for Audioholics and have a slew of headphones to test the Emotiva Stealth DC-1 with. With no headphones did I get close to taxing this unit. While I'm sure there are some headphones that can do it but I haven't run into them yet.

Remote

Emotiva has almost always provided small(ish) rectangular remotes with their products (some exceptions of course). This one is completely different and I have to say that I mostly love it. It is non-backlit (which isn't surprising), is long and thin, and is constructed out of aluminum or steel (it is heavy). The metal is fairly smooth but the bottom is concave so that it is easy to grasp. There is no specific indentation to ensure that your hand is in the right place but it isn't too hard to figure that out (especially since you'll need the lights on to use it). As backlighting is one of my hot buttons, I'm going to give the Stealth DC-1 a pass based on where I believe its intended placement (office or studio).

The button layout isn't the most intuitive but perfectly functional. There are dedicated on and off buttons (really standby buttons as the main power switch is on the back). Oddly, the display dim button is directly below the power buttons followed by volume up, mute, volume down and the specific input buttons. This indicates to me that Emotiva thinks you'll use the power, dim, and volume control buttons the most. I disagree with one of those. I'll let you decide which.

Stealth DC-1 DAC Setup and Sound Quality

Ah, the screwdriver. Emotiva has included a small screwdriver with the Stealth DC-1. At first, I thought it was for the remote - and it is, at least in part. To access the battery compartment, you need to remove two small screws and remove the end plate. You then slide off the entire bottom to access the two AA batteries. To use the remote the first time, you'll need to remove the tab that is keeping the batteries from making contact.

But that's not all the screwdriver is used for.

What? What is he doing?

The Stealth DC-1 is shipped with a 2dB bass boost at 20Hz. Emotiva states that many headphone amps have this bass boost to compensate for many headphones’ frequency response. As most headphones won't get anywhere near 20Hz with meaningful output, this is debatable. The bass boost is defeatable but you'll need to take the top off the Stealth DC-1 by removing six screws. There are two tiny jumpers that will have to removed with tweezers (they are really, really small) and replaced in a different configuration to turn off the bass boost. While it may be common in pro gear to have to disassemble it to change configurations, it's fairly unheard of in consumer level gear.

I labeled the jumpers with fancy arrows and everything

At this point, you are ready to plug your Stealth DC-1 into the wall and get going. If you have a Windows computer, you'll want to download the drivers from the Emotiva site but Macs will recognize the Stealth DC-1 out of the box. You may have to go into your audio settings to get it to switch to the DC-1 but you'll have to play with the settings of your computer to see.

The Emotiva Stealth DC-1 recognizes all the sample rates and bit depths on the market from 16/44.1 to 24/192, including 24/88 and 24/176.4. It does this automatically and will display the sample rate on the screen (but not the bit depth) along with the input type during playback. From the menu (which can only be accessed from the front of the unit and not from the remote), you can select SRC (Sample Rate Conversion - Synchronous or Asynchronous), Mute Level (-20dB, -40dB, and Silent), Output Mode (Variable - for headphones, Fixed - for pass-through), USB Mode (2.0 or 1.1), and Info (tells you the software version number).

Itty bitty is the right term

I set the Stealth into asynchronous mode, the mute to silent, USB to 2.0, and output to variable. It is important to note that the Mute Level is not in reference to your current level. If you select -20dB, it won't bump down your volume -20dB from your current level. Instead, it switches the volume from wherever you have it to -20dB (which, for me, was often louder than I was currently listening). The Stealth DC-1 remembers your volume levels for your headphones and will switch to the last volume when headphones are inserted. When you remove the headphone, it will switch to the last non-headphone volume level. The headphone outputs share a volume level.

Sound Quality

Lost bits are lost bits - that is something you want to remember. If you got excited about how many songs you could shove on your iPod and compressed everything down to 128kbps MP3s, well, no DAC can fix that. It will be jitter free, zero noise floor playback but it will still sound compressed, tinny, and emotionless. The same is true if the original recording or mixing was done with sub-standard equipment. You can't fix that after the fact. All the Emotiva Stealth DC-1 can do is playback your music as it was recorded or mixed. If it was recorded, mixed, or compressed poorly, it is still going to sound like garbage.

There were a couple of things I was worried about with the Emotiva Stealth DC-1. I wanted to make sure it worked with a wide range of headphones, I wanted to make sure that it was compatible with all the formats Emotiva claimed, I wanted to make sure it didn't introduce lag, and I wanted to ensure that it really did eliminate jitter.

Space is at a premium inside as well

As I've already said, I tested the Emotiva Stealth DC-1 with a wide variety of headphones. I used the OM Audio INEARPEACE in-ear monitors, Audio-Technica ATH-M50s over ear, V-MODA Crossfade M-100 over ear, Sennheiser Momentum over-ear (review pending), and more. I plugged in everything from $20 headphones to well over $300 headphones and never did the Stealth DC-1 hiccup.

The OM Audio INEARPEACE, in particular were a troublesome pair of headphones as they were very sensitive. In the normal headphone output of my Mac laptop, there was a more than audible and very annoying hiss that could be heard through them. When I switched to the Stealth DC-1, the noise floor was absolutely gone. Dead silent. This is what you want out of a headphone amp and the Emotiva provided it.

I'm not a big proponent of upsampling but it is easy enough to do it with a computer source. Starting at 44.1kHz and 16-bit depth, I moved through 48k, 88.2k, 96k, 176.4k, and 192kHz testing 16, 24, and 32-bit depth with each. The Emotiva Stealth DC-1 had no problems with any of them and switched cleanly displaying the correct sampling rate on the display for each.

There's the fuse. Not sure why I took a picture of this. I also have a picture of the manual.

Any psychologist or researcher will tell you that you can never prove the null hypothesis. That's just a fancy way of saying that you can never prove that something isn't there. That's why we are still seeing Ghost Hunter shows and other nonsense on TV. A lack of evidence just means (to them at least) that they haven't found the evidence yet (or come up with the right tool...blah, blah, blah). It's still possible and while that is technically true, at some point you just need to let it go.

It is possible that some jitter or coloration might get through the Emotiva Stealth DC-1 but I never heard it. I tested it with high-res files and garbage from iTunes, Pandora, and more. In each case, the Emotiva Stealth DC-1 got out of the way and just let the music play as was intended (or recorded). From their website: "Emotiva Pro’s all-new Stealth DC-1 provides an accurate, transparent window on your work" and "You’ll hear what your source really sounds like." Emotiva's intent was to provide a transparent link between your digital source and either your headphones or the rest of your gear. As I have no evidence that they've failed I must conclude they succeeded.

Emotiva Stealth DC-1 DAC Conclusion

If the Emotiva Stealth DC-1 DAC, headphone amp, and preamp does what Emotiva intends, you'll never hear it. That's right, the whole point is to get out of the way and let your source shine. The $500 price tag would be worth it for the DAC and headphone amp or the DAC and preamp alone but Emotiva gave you all three for that price. That's amazing from a company that I thought was done amazing me. The Emotiva Stealth DC-1 - if it isn't on your Christmas list, you need to reevaluate your priorities. Highly recommended!

Emotiva Stealth DC-1 DAC

MSRP: $499

www.emotiva.com

The Score Card

The scoring below is based on each piece of equipment doing the duty it is designed for. The numbers are weighed heavily with respect to the individual cost of each unit, thus giving a rating roughly equal to:

Performance × Price Factor/Value = Rating

Audioholics.com note: The ratings indicated below are based on subjective listening and objective testing of the product in question. The rating scale is based on performance/value ratio. If you notice better performing products in future reviews that have lower numbers in certain areas, be aware that the value factor is most likely the culprit. Other Audioholics reviewers may rate products solely based on performance, and each reviewer has his/her own system for ratings.

Audioholics Rating Scale

• — Excellent
• — Very Good
• — Good
• — Fair
• — Poor

Metric	Rating
Two-channel Audio Performance
Build Quality
Fit and Finish
Ergonomics & Usability
Ease of Setup
Features
Remote Control
Versatility
Performance
Value