DAC 4 TJ: Sound Card for Tango DJs

1. Introduction

The question “which sound card should I get” arises periodically in various DJ forums. The answers are often reduced to “I use card X, it’s the best!”, with an inherent possibility of a local religious war. The truth, however, is that nowadays there are plenty of good sound cards out there, with very reasonable prices and widely varied feature sets, and so you can make much better choice by looking at the specific features of the card that you need, rather than listening to someone’s opinions on what is “the ultimate best”.

In my not so long career as a tango DJ I have owned 12 (twelve) various sound interfaces, and tried out many more. In this article, which emerged out of the Sound Engineering for Tango DJs seminars, and discussions in several Tango DJ groups, I will try to present a feature-centered, rather than opinion-based view on various classes of sound cards, suitable for Tango DJs, without delving too much either into the misty worlds of audiophile legends or stepping onto perilous grounds of digital sound quality issues.

Please note that in this article “sound card”, “sound interface” and “DJ interface” will all refer to the same thing, namely, an audio unit that converts a digital stream sent over USB connection of your computer into the analog, line level signal, which, in turn, is sent to the house sound system. “DAC”, depending on the context, may refer to either a sound card as a whole, or to Digital to Analog Converter chipset inside of a sound card.

2. Features

Obviously, the first reason for getting a sound card is a quest for better quality of the sound. However, a well-chosen sound card can give you much more than just a quality boost. Moreover, sound cards of a similar price, and similar quality may have almost orthogonal sets of features, with some of them being extremely important for your particular way of DJing, while others may never be needed. And yet, when you buy a DJ sound card, only a fraction of its price directly reflects the quality of the sound. So, would it not be wise to look at all those features, before committing yourself to a particular brand or make?

2.1. Two Channels vs. Four Channels

If you want to pre-listen to your next track/tanda, while playing, there are three ways in which the sound card can help you.

Reloop Play: four channel DJ soundcard with two stereo RCA outs in front and additional headphones jack on the back

1. Four channels (e.g. two stereo channels) sound cards have two separate stereo tracks – one for FOH (Front of House, or venue’s acoustic system) and one for cueing (pre-listening). A proper DJ software, such as Traktor Pro, will detect such card and configure it so that you can play and pre-listen from the same instance of the same player. All DJ class sound cards are four channels, and some professional audio interfaces, also have four channels DACs.
2. Traktor Pro and similar software will also allow you to configure any single stereo channel, be it a computer audio jack, or an external two channels sound card, to play your music, mixed down to mono, into one channel, and your cue, also mixed down to mono – to another channel. Then, using a special adapter  (see Traktor DJ cable), you connect the house to, say, L channel, and your headphones to R channel, and so, you can pre-listen to your music even without an external sound card at all, or with the mere two channels card. In short – if the main reason for buying sound card is the necessity for pre-listening, a combination of a DJ player and DJ cable will give you this ability without sound card at all.
   

   AudioQuest Dragonfly 1.5 Black: Two channels sound card with a single, 1/8″ mini-stereo out

3. If you do not have a DJ-style player, or simply annoyed or intimidated by it, there is yet another solution. On Windows, you can start two instances of any player that allows you to configure where its output goes, for instance, Foobar, then configure one instance of the player to send the stereo stream to the sound card, which is connected to FOH, and another instance – to send its stream to the computer audio jack, to which you connect your headphones. On Mac OSX you will need to use two different players, for instance, configurable VOX, connected to the sound card for FOH, and plain and simple iTunes for pre-listening.

As you can see from the above, while four channels DJ sound cards indeed allow very simple way of pre-listening to your music, you will still require a player that can work with such card, e.g. without such player, your four channels card is simply useless. At the same time, any professional player, that allows to configure individual channels, such as Traktor or MIXXX, or a player with configurable output, such as Foobar or VOX, can also facilitate pre-listening into a plain two channels sound card.

2.2. MIDI interface

Traktor Kontrol Z1: DJ sound card with MIDI interface

For the purposes of this article only, MIDI is a special hardware protocol, which allows you to push real buttons and rotate real knobs, instead of using your mouse, when playing music on your computer. While we do not do any “scratching” or “beat-matching” as other DJs do, having tactile control over your DJ player is certainly a big bonus… that is, if your DJ player itself allows such control. So, if you already use Traktor Pro, or MIXXX, or MegaSeg, or a similar player you might be interested in getting a sound card, which, on the top of processing your sound will also allow you to load/start/stop your music, fade cortinas, turn on/off pre-listening, control the equalizer, and the pitch, etc., all with dedicated physical controls, and colored LEDs for the feedback. And, what is even more interesting, you can assign pretty much an arbitrary action to any control element of such an interface, thus tailoring a generic MIDI controller to your specific needs.

The possibilities there are limited only by the number of buttons and knobs on your card, and your own imagination. At the same time, if this card does not have other features that you consider crucial, you may as well get the card with all needed features, and experiment with a stand-alone DJ MIDI interface, such as rather inexpensive, yet, quite capable Numark DJ2GO. In case you wonder what can you do with those large scratch-wheels, just think of scrolling through your tandas, collections, etc.

In the following gallery there are three examples of controller mapping, from very simple “what do I do with those knobs” for Traktor Z1 to rather evolved mapping of my own DJ2GO.

Simple Traktor Z1 mapping utilizing “useless” buttons and knobs

Not so simple Traktor Z1 mapping with playlist controller

Dj2Go mapping that controls both Traktor Pro and Audio Hijack running Paramertic EQ and Compressor plugins

2.3. Sound Quality, or Hitchhiker’s Guide to HiFi audio forums

Sound quality is the subject of endless debates in various HiFi aficionado forums, inherently plagued with highly subjective opinions. My personal preference would be to avoid this topic altogether, but it is rather difficult to do in the article on the sound cards. And so, here is my personal, very subjective opinion, based on many cards that I either owned, or compared.

In the live Tango DJ environment, almost (!) any sound card in $100 – $200 price range from a reputable manufacturer, such as NI/Traktor, AudioQuest/Dragonfly, Focusrite, Steinberg, FiiO, Numark, Mackie, Allen&Heath, Roland, and so on will sound just great. A card with a significantly higher price tag will sound even better indeed, but, as soon as you get into HiFi world the rule “twice the quality, ten times the price” will start taking its toll.

Very subjectively, I divide for myself all the sound cards by the type of sound that they produce into four big classes, namely, “punchy” DJ sound, “purring” HiFi sound , “clean” professional sound, and also crappy sound of most of the laptops, phones, and tablets alike. However, the quotes in the first three categories are there to remind all the readers, that the one to three distinction is rather minimal. Objectively, there is simply good, agreeable sound, produced by a decent sound card, and harsh, tingling sound produced by your computer or iSomething when you play in a milonga venue at high volume levels. When you play your music at home, at low volume, you might not hear any difference at all, unless you own a HiFi system or a pair of professional grade monitors, and you play your music at high volume.

Having said that, let’s briefly look at the major components of a sound card, in case you decide to plunge headlong into countless HiFi reviews.

2.3.1. Digital to Analog Converter

Arcane circuity of a popular HiFi DAC, Shiit Bifrost

The DAC (Digital to Analog Converter) is the heart of the sound card. It transforms the stream of ones and zeros into the analog electrical signal, e.g. either current or voltage, also applying a sophisticated low-pass filter to the resulting sound in order to cut down the high frequency noise, inherent to the process of digital to analog conversion. This high-pitched, tingling sound is usually called “digital jitter”, and it has multiple causes, inadequate resolution of the source file, or bad low-pass filter being only two of them. There are specialized, proprietary DAC chipsets in the CD players, digital mixers and sound processors, etc., but also general purpose DAC chipsets in all the various sound cards that are connected to computers.

The most heralded, yet not so much important characteristic of a DAC is its resolution, which can be as low as 16 bit / 44.1 kHz, and yet, provide amazing musical sound, as, for instance, it was the case for the original proprietary DAC in ReGa Planet CD player, or as high as 32 bit / 384 kHz in some modern upsampling chipsets. Most of the music that we play is, indeed 16 bit / 44.1 kHz, except for some newer TangoTunes transfers, and, from this point of view, even the lowest resolution is fine for our purposes. At the same time, higher resolution rates point to the newer DAC chipsets, and those, in general, produce better sound, when compared with similar earlier models.

In the Hi-Fi world three the most known brands of DAC chipsets, in no particular order, are Burr Brown, Sabre and Wolfson. Among those three, only Sabre trademark is still own by its original company, ESS Technology, whereas the other two have been bought by the larger chip manufacturers, namely Texas Instruments and Cirrus Logic. In audiophile realm the endless debates X vs Y vs Z are continuously held, each new subversion of a chipset is meticulously compared with the previous one… with lots of metaphors, parables and expletives… but without any meaningful and/or conclusive arguments whatsoever.

At the same time, very well known in the professional audio engineering realm Focusrite Group makes their Scarlett USB interfaces using Cirrus Logic chipset, produced in 2004… and you know what? This sound card just sounds great. Clean, clear, and punchy enough for all intended purposes of Tango DJing.

If you are just looking for a good DJ card, particular DAC model, or its resolution, should be the least of your worries, as any modern DAC chipset from the above three, or even not-so-modern one, such as Cirrus Logic CS4272, used in the original Scarlett product line up to 2017, will sound just good enough… which is, once again, a subjective opinion of the author, based only on his personal experience.

2.3.2. Asynchronous Transfer Mode

Before the digital stream reaches the DAC, it needs to be received from the host computer, via USB connection. A special USB receiver chipset is required to perform so called isochronous transfer between the computer and the sound card, used for streaming real-time data such as audio or video. The data is streamed at full speed, at a very precise rate, but only in theory. In practice, when the receiver operates in the simplest, synchronous mode, solely relying on the computer clock to push the data to the receiver, the transmission rate is affected by various activities in the computer, ultimately adding its share to the digital jitter.

Could anything be done about it? Indeed, a rather unique chipset, TAS1020B, developed by Texas Instruments, allowed to turn the table around. Now it is the device itself that “pulls” the data from the USB connection at a precise rate, controlled by its own clock, thus eliminating at least one source of the jitter. This is called asynchronous transfer mode (ATM), in addition to many already existing ATMs. The full story is a bit more complicated than that. Besides synchronous and asynchronous modes of isochronous transfer, there is also adaptive mode, and some manufacturers, for certain technical reasons, strongly prefer it to asynchronous mode. Besides TAS1020B there are other chipsets, such as Tenor TE8802L, capable of both asynchronous and adaptive transfers. And, finally, ATM became a highly desired feature only in the HiFi DAC world, while largely ignored by manufacturers of all other sound card classes.

Then how important is ATM for Tango DJing? First of all, the data rate fluctuation is only one, and not necessarily major contributor to the digital jitter. Also, we need to remember that all of the Golden Age recordings have a fair (and, often, rather unfair) amount of groove noise. When we try to combat the groove noise with the hardware equalizer, located downstream of the sound card, we destroy the high-frequency content, thus effectively eliminating the jitter as well. But even if we choose to ignore the groove noise altogether, the noise itself masks the digital jitter. On the top of it, high-frequency content is very effectively destroyed by the mediocre club sound systems that we routinely use on our milongas, and is also softened (dampened) by the dancing and chatting crowd.

I would be lying to you if I stated that I do not care about the jitter. I certainly do, and the choice of my home stereo system, which is one of the warmest on the market, was indeed heavily influenced by the jitter issue of the classical CDs that I used to listen to a lot. The DAC, connected to my home stereo indeed has ATM receiver. But returning to tango DJing realm, I am, personally, very happy both with my Dragonfly card which has some latest and greatest ATM USB chipset, and with my Scarlett 2i2 converter, which does not, or with plain and simple Traktor Audio 2 card that I used to have, even though I might be able to consistently tell one card from another on the blind test.

2.3.3. Output Circuitry

After the electrical signal gets out of the DAC, it travels through the coupling circuitry into the op-amp. The latter is an integrated pre-amplifier, which task is to provide a standardized voltage level for the line outputs, or to supply power for driving the headphones. Once again, there are a lot of heated, yet fruitless discussion in HiFi forums, which op-amp is the best, which kind of coupling capacitors provide “wider and taller sound stage” and so on, and while there are, indeed, audio-grade op-amps and better quality capacitors, believe me or not, the engineers, who design the sound cards, do possess necessary knowledge to make intelligent choices, and indeed strive to provide you with the best possible solutions. And so, the claims of some tinker-itchy audiophiles “I swapped op-amp X with op-amp Y in my thousand dollars DAC and now the music is indeed unveiled” sound ridiculous at best.

At the same time, an inadequate on-board output circuitry, not the DAC chipset, is, most probably, the main reason why there is so much difference between the sound coming out from the laptop audio jack, and the sound coming out from any of the sound cards, mentioned in this article.

2.3.4. Conclusion

The only conclusion that I was driving at in this section is that the sound quality of a sound card from a reputable manufacturer, or characteristics of its components should be least of your concerns when you chose the card for DJing. Look at all the other features, which can indeed enhance your workflow, let you save money for better transfers of the music, allow you to travel light, enable you to easily connect to various house sound systems, and so on.

A typical sound chain – do you still believe that sound card alone will solve all your problems?

If you really want to delve into the issue of good sound, get a book on sound engineering and psycho acoustics and learn how to deal with inadequate sound halls and how to enhance your sound, using available tools… and just rest assured that the sound quality of the sound card itself is not the weakest link in your sound chain.

If you are not convinced – arrange your own blind tests with another DJ, before or after the milonga in the venue where you often play. Or, you can even connect two cards to the house mixer, switch them during the announcements, and then ask your trusted peers in the audience if they could hear any difference at all. But you have to make sure that both of your cards are set exactly at the same sound level, otherwise your results will be heavily contaminated by “louder sounds better” phenomenon. And when  you are finally convinced that you indeed found the best sound card – just go ahead and treat yourself to it without any hesitations.

2.4. Additional Inputs

Focusrite Scarlett Solo: Sound card with additional mike and line inputs, gain knobs and phantom power button (lit in red)

If you have a habit of announcing the tandas, or simply like to have your own microphone, you will need a sound card with a microphone input, in addition to the  USB input. Also, in case the performers come with their own music on iSomething, a separate line input would come handy. Some sound cards, namely, the ones from the professional recording interfaces class provide just that – either dedicated microphone and line inputs, or two combo jacks that allow to use either a microphone or an additional line source.

A word of caution. Usually, the sound card with microphone inputs will have a small button labeled “PHANTOM” or “+48V”. Make sure that this button is OFF any time when you connect your microphone to it. Most, if not all, dynamic microphones will ignore this additional voltage, however, some cheap/strange ones will get burned. And, while we are on the subject of the microphones, if you are currently looking for one, the only types of the mikes you should be considering must be “dynamic with cardioid pattern”. Any other type of the microphone will be either creating terrible feedback with the speakers, or be unnecessarily expensive, or too fragile, or any combination of the above.

2.5. Balanced vs. Unbalanced Outputs

Consumer grade unbalanced  2xRCA to 1/8″ mini-stereo cable

The usual consumer cable to transmit a signal from, say, CD player to the power amplifier has two wires in each of its stereo channels – one for the signal, and another one for the ground. This is quite sufficient for home audio, but it is as well sufficient for a reasonably short DJ cable sending the signal from your sound card into the mixer. If on the back of the card of your dream you see either a pair of RCA sockets, or a single mini stereo socket your output is certainly unbalanced.

However, when the cable is either very long and the source signal is weak, which is usually the case with stage microphones, guitar pickups, etc. or the cable is short but the electromagnetic interference around is very high, which is usually the case for the tightly packed equipment racks, balanced cables are used. Balanced cable contains three wires for each mono channel, two for the signal in the opposite phases, and the third one for the ground. On the receiving end the two audio signals are subtracted, thus effectively doubling the signal itself, and eliminating most of the noise that was picked up on the way.

Professional balanced XLR female to TRS mono cable

Better (more expensive) sound cards provide balanced outs, which is a mixed blessing. If you want to completely bypass the house sound chain and connect directly to the powered speakers, then balanced outs is your only option. If you are building your own PA, and decided on powered speakers, then, again, balanced outs are the best option, even if your cables are not very long. If, however, most of the time you are faced with a regular house mixer, or rather odd consumer grade amplifier in a local cafe, you will have to carry both your own balanced cables for the mixer, and several adapters stacked one on another for the cafe.

If you do use adapters, you should understand the difference between passive resistor balanced output, low-impedance active balanced output, cross-coupled (servo) active balanced output, and also transformer balanced output, and also be able to find out which one is used in your sound card. To unbalance active output you must float the cold pin, to unbalance servo or transformer output, you must tie the cold pin to ground, and use either solution for passive balanced.

If the last passage sounds like Chinese to you, simply make sure that the card of your choice has an option of using unbalanced outputs and use those when DJing in odd places. Otherwise you risk either severely distorting your sound, or, in some cases, even burning out your precious sound card. However, if you are curious and adventurous enough, you can make (or order to be made) your own signal cables, for any possible combination of ins and outs, following excellent specifications in  Rane Note 110 “Sound System Interconnection”. You will only need one type of special cable, to cover the most troublesome case of unbalanced-out / balanced-in or balanced-out / unbalanced-in for your particular card of choice.

2.6. Volume Controls

A big lie: the oversized volume control knob of this four channels DJ card is right there, but as it turns out it controls only the headphones. Read the specs!

When your card is connected to the house mixer, you have channel gain, channel fader and main faders all at your service, to set up the best gain structure throughout the sound chain, to fade cortinas, and to control the overall volume in the hall. However, when DJing in small places, a single volume knob of the power amplifier may not be within an easy reach, or not accessible at all. The worst thing that a DJ can do in such case is to control the volume in the digital domain, e.g. through his computer. It is one thing just to fade the cortina, and then go back to full digital volume, but it is completely different thing to run the whole show at, say, quarter of the full volume. By doing that you destroy the dynamics and the quality of your sound. Once again, I have to refer you to special literature for the proof of this statement, but for now, I can only say that if you ever DJ in the places, where volume control must be performed from your computer, not from the house mixer, do not buy a sound card that does not have a big, friendly knob labeled as “Volume” or “Output level”.

2.7. Phone/Tablet connectivity

FiiO E18 Kunlun connected with OTG USB cable to Android phone. Three quarter of the card’s enclosure is occupied by a 4000 mAh battery

The latest fashion in the sound card design is to allow the sound card to be used with a smartphone or tablet. In order to do that, first of all, a special adapter is needed. It is so called OTG cable for Android devices, or ever-changing adapter for iSomething products.

Besides the adapter, there is an issue of power consumption, which has at least three solution. The newer Traktor Audio II and Traktor Kontrol Z1 require an external power adapter to be plugged into the card, which, in my opinion, completely defeats the purpose of playing with a mobile setup (the adapter is not needed when you connect those cards to the laptop). The FiiO Kunlun card has its own battery with rather large capacity, which also can be used to charge the phone in an emergency, but not while you are playing the music. And, finally, the Dragonfly 1.5 (Red and Black edition) swapped the old TI receiver chip with a newer ATM chipset, and achieved such low power consumption that, at least by the manufacturer claim, any phone will be happy to play through this card.

Personally, I tried using smartphone with the Kunlun, but only to find that playing full milonga on PowerAmp is much more tiresome, than lugging over the laptop, even for the cozy home parties.

2.8. OS Compatibility and Sound Drivers

Even though  most of the nowadays, two channels USB sound cards are plug-n-play, some of them may require installation of the manufacturer drivers, while other may simply not be compatible with the current version of your OS. A major OS upgrade may cause a huge headache, especially if you laptop is of considerable age. The upgrade might make it run much slower, shorten the battery life, or break your DJ player, DSP chain or some other important application. If you do install the manufacturer drivers, you must check for the updates periodically, and definitely upgrade the drivers together with the next OS upgrade.

At the very least, do a meticulous check of hardware and software requirements, and think of all consequences, if the sound card of your choice does not support the current version of your OS.

2.9. Size and Weight Factor

Halide HD DAC, despite its size was considered one of the best DACs in the under $1000 category

For any USB powered card the sound of this card has no connection whatsoever to its size or weight. A recent winner of many praises along audiophiles and DJs alike, AudioQuest Dragonfly is packed into a USB flash drive enclosure, another little wonder of HiFi, Halide HD DAC has a size of Zippo lighter, most of professional audio interfaces are of the size of a truffle box, while Traktor Kontrol Z1 or XONE:K2 are intended, by design, to precisely fit the depth of a DJ turntable, thus being the bulkiest among all.

The weight varies considerably as well, from mere 100 grams or so for Dragonfly to about a kilogram for Scarlett 2i2. A larger card may provide more controls and more output options, however, when you travel a lot, weight/size factor may become more important than many other features.

2.10. Price Factor

All of the sound cards, reviewed in the next section of this article fit into approximate range between $100 and $200 before tax, as listed in http://www.bhphotovideo.com/ .

As my experience shows, sound cards with list price significantly less than $100, such as the cards in Behringer UCA family, are grossly inadequate for any of the advertised purposes, be it sound reproduction or sound recording.

Sound cards significantly more expensive than $200 are inadequate as well, if the sole purpose of buying such card is to play music in the milongas.

Woo Audio WA7 Fireflies glowing in the dark: impressive, isn’t it?

The second statement needs some clarifications. When you are choosing a sound interface to complete your well-thought sound chain, which includes each and every component, starting with best quality transfers, the HiFi DAC of your choice, for instance from Shiit family, will cost you as much as it needs to be and will be worth every penny of it. If you are a traveling musician or a sound engineer, you certainly might consider hi-end converters such as RME Babyface, or even converters with hardware accelerator such as UA Apollo Twin.  If watching warm glow of a vacuum tube overflows your heart with joy, and then you pour it all out onto the milonga floor, by all means, get yourself a WA7 Fireflies, even with a dedicated vacuum tube power block, to double the glorious glow effect. But if it is your first, or, maybe, second sound card, you might want to be a bit conservative in your choices, and stay in the suggested price range.

2.11. Not so Obvious…

So far, we were looking at additional to digital-to-analog conversion features, provided by various sound cards. However, a decent DAC can be found in somewhat unexpected places within our stated price range.

Firstly, all FiiO X-series music players, such as X3 2nd gen can also serve as USB sound cards. So, if you are choosing between a portable player and a sound card, you might as well have both for the price of one.

Also, the newer generation of mini-mixers often have 2-channel USB in/out connection. If you are looking for a compact mixer to complete sound setup for a new milonga venue, you might want to check out, for instance, highly recommended, miniature AG03 mixer from Yamaha, larger, yet quite portable ZEDi-8 mixer from Allen & Heath, or, if you want to keep the mixer in the venue, you should give a try to ProFX8v2 from Mackie. Alternatively, you might want to explore similar options from other manufacturers, although my personal recommendation would be to avoid all cheap Behringer USB mixers.

3. Sound Cards Review

In the following review, I will, once again, concentrate the attention on various features, offered by the different classes of the sound cards, and provide examples of some typical cards in each class. In terms of the sound quality, I can only vouch for the cards that I have actually used myself, or heard on multiple occasions in the familiar milonga environments. Those specific models are:

• NI Traktor Audio 2 – only the first release, presently discontinued
• NI Traktor Kontrol Z1
• Numark DJ IO – only the first release, presently discontinued
• Audioquest Dragonfly 1.2
• Audioquest Dragonfly 1.5 Black
• Audioquest Dragonfly 1.5 Red
• FiiO Kunlun E18
• FiiO X3 2nd gen – portable player that may be used as DAC as well
• FiiO K3 – my current (2019) choice for backup and traveling with minimal weight
• Focusrite iTrack Solo (original and MK2)
• Focusrite Scarlett 2i2 (original and MK2)
• Mackie Onyx Blackjack – only the first release, still available
• Halide HD DAC – by its sound quality the best of all listed sound cards, used by myself and another local DJ, this DAC did not make into the review, because of its steep price tag, and also because its manufacturer, Halide Design seems to stop all production and close down a few years ago.
• Audient ID4 – built like a tank professional 2-channel interface with lots of additional options for seamless DJ workflow. This is my latest choice for the primary, professional sound card, and occasional recording sessions.
• Behringer Q502 USB – cheap, yet versatile utility mini-mixer, but the digital sound quality is very poor, do not use it as either DAC or ADC.
• Apogee One for MAC – convenient, yet, very unreliable sound card, no longer recommended to anyone
• RME Babyface, Sound Devices USBPre-2, UA Apollo Twin – all those, without any doubt great sound interfaces with wealth of features, which I have listened to and handled on multiple occasions, are in the price range of $800 – $1000, which is beyond the purpose of this article. Out of these three, I was once interested in USBPre-2, but every feature that I really needed was also available in Audient ID4, so it ended up as my current choice for my primary interface.

3.1. DJ Sound Interfaces

DJ sound interfaces are, by definition, four-channels cards. Their designers are not overly concerned with either getting the latest and greatest DAC (or op-amp, or capacitors), and quite shy about stating what was actually used. The outputs are usually unbalanced RCAs for the house, and mini-stereo for the headphones. Some of the cards have additional microphone input, but the majority doesn’t. The volume controls both for the house and headphones are almost always present. Those cards are solidly built, and can take a lot of beating. Larger ones usually have a slot for a Kensington lock. Some of those cards have MIDI knobs and buttons. The DACs are usually limited by 24 bit / 44.1 kHz resolution, which is the lowest, compared to other classes. In terms of sound quality they are on a “punchier” side.

3.1.1. Traktor Audio 2

The old Traktor Audio 2 sound card with large 1/4″ outputs in the front

In its first version, no longer produced by Native Instruments, this was an elegant, solidly built, smaller than a cigarette pack card, with two 1/4″ connectors on the front,  two volume wheels on its sides and two green level indicators, which came extremely handy when hunting for a broken sound chain. This card was used and recommended to use by many DJs around the world, it was the first sound card that I bought, and I was very happy with its performance. Currently you can get it only in the aftermarket. With the original price of $100, at the time of writing it could be easily found on eBay for around $65.

As soon as this article was published, I have received several comments that the newer, Traktor Audio 2 Mk2 card, which looks almost the same as the old model, and which, as I apparently wrongly assumed to have the same sonic characteristics, in fact sounds like “the output of a cheap computer“.  And so, I could only recommend you to search for the old model, shown on the picture above, and avoid the new one, currently available in the stores. The easy way to tell the difference is to look at the inputs and outputs of the card. On the old one, the input was USB-B type, and the outputs were professional 1/4″ jacks. On the new one – mini USB for the input and 1/8” mini-stereo jacks for the outputs.

eBay listing: http://www.ebay.com/sch/i.html?_nkw=”traktor+audio+2″

3.1.2. Traktor Kontrol Z1

At the other end of the price range lies another offering from Native Instruments – pretty much the same card as the old Audio 2 from the sound point of view, but with a capable MIDI interface. Large knobs and faders with a solid feel, multi-colored buttons, plus a nice bonus – multi-segment level indicator for each channel. Once again, even though the card has an appearance of a DJ mixer, it is not. Its knobs and faders do not do anything else beyond sending specially encoded signals to your DJ player. Unless your player is MIDI capable, and you are willing to spend time on completely re-programming this card to suit your needs – don’t buy it. The reverse statement is also true – I spent countless hours playing with the MIDI controls until I’ve got my perfect workflow . If you decide to get it, also buy a carrying case for the card – you will never regret it, however, be aware that this card is quite bulky.

The house outputs are a pair of RCAs. For this, or any other card with RCA outs, you will need your own 2xRCA to mini-stereo adapter in an unfortunate case when you are handed the receiving end of a DJ cable and told that “nothing can be reconnected”, or simply when the amplifier cannot be easily reached (on a high shelf, locked, etc.)

Manufacturer page: http://www.native-instruments.com/en/products/traktor/traktor-for-ios/traktor-kontrol-z1/

3.1.3. Other DJ Cards and MIDI Controllers

Numark DJIO price tag lies even below $100 level. A solid performer, used, in its first version, for many years by one of the local DJs, this card has an additional microphone jack, 2xRCA outs, and two control knobs – for the headphone volume and for the microphone gain. Unfortunately, there is no volume control for the house. As I have explained before, I would never consider buying such a card myself, but otherwise it was, in its first version, a decent card with a very modest price tag.

Manufacturer page for Mk2: http://www.numark.com/product/djio

The new release of a versatile Numark MIDI controller, Dj2Go v.2 now also also includes four-channel sound card, making it a serious contender of Traktor Z1, for amazing $80. If you are looking for an average quality DAC, yet, lots of MIDI features, you should definitely consider this one.

Manufacturer page: https://www.numark.com/product/dj2go2

AKAI Serato DJ is another sound card / MIDI controller combo. At $250 it is over our price range. However, this interface comes with a better 24 bit / 96 kHz DAC, ships with full version of Serato Pro DJ player, and has more than enough controls to facilitate all your DJing needs including browsing and navigation.

Manufacturer page: http://www.akaipro.com/product/akai-amx

3.2. HiFi Headphone Amplifiers

The HiFi headphone amplifiers variety emerged from the sad fact that both computers and phones internal sound cards were, and still are, quite mediocre, both in terms of sound quality, and in terms of sheer power they can deliver to the HiFi headphones. The emergence of high-definition music created a nice niche for those, and some of the offerings are indeed well suitable for our purposes.

It is important to understand that a DJ sound card has at its end so called “line preamp”. This line preamp needs to only deliver sufficient voltage (e.g. up to +4 dBu or 1.2 V) to the high-impedance input of the mixer or power amplifier. The power, delivered by this preamp is negligent, because of the high resistance (over 10 kOhm) at the receiving end.

The headphone amplifier, on the other hand, need to deliver both higher (up to 5-6 V or even more on the phone jack of a mixing console) voltage, and also considerable current as well, provided by an additional, current amplification stage, in order to get the coils in the headphone speakers moving and producing the sound waves.

If the idea of using power amp (and it is a power amp indeed, even though its maximum power rarely, if ever, exceeds 1 Wt) in place of a line preamp sounds repulsive to you, consider that this power amp is given a really easy job when connected to the line input. There is no current to pump through, because of very high resistance of the line in, there is no back-EMF to fight, because there are not any moving coils on the other end, and so on. In theory, it might overload the line-ins with too hot a signal, but, as long as you are connecting to the professional equipment, which can handle routinely levels up to +18 dBu, it is not a problem at all, and you still have your gain knob to trim the signal, if so needed. You only need to exercise caution, and lower the output level of the headphone amplifier, when you are connecting to a consumer line-in, with its -10 dBV (0.3 V) nominal level. However, you still have your ears to alert you in case of a distortion, and also to convince you that those headphone amplifiers indeed produce wonderful sound.

There are quite a few advantages in using headphone amplifiers for Tango DJing. First of all, it’s the size/weight factor, combined with high quality components and high resolution rates. Also, this is the only sound card class, aside of HiFi DACs, which is more often than not equipped with ATM USB receiver chips. And those cards have to compete for the attention of the consumer market, meaning that their quality gets indeed better, while their prices drop lower and lower. In general, the sound of the cards in this class can be described as pleasantly “purring”. Also, the headphone amplifiers are usually plug-n-play on wide variety of hardware and operating systems.

But there are disadvantages as well. Those cards are strictly two channels, with minimal controls, usually without any additional inputs, with puny mini-stereo jack for output, and, worst of all, quite unreliable micro-USB digital input.

3.2.1. AudioQuest Dragonfly

The very first edition of Dragonfly, a mighty sound card in the enclosure of a USB flash drive got raving reviews from the HiFi magazines. The second edition, Dragonfly 1.2 dropped the price from $200 to $130, and the current, Dragonfly Black 1.5 sells for mere $100, with all the internals being completely redesigned by restless AudioQuest engineers. There is also Dragonfly Red 1.5 with higher resolution and output voltage, but for our purposes the Black edition is more than sufficient.

I would never consider getting this card when it just appeared on the market. No volume control – no deal. Right? Well, in case of Dragonfly – wrong. As it turned out, this card “senses” the computer volume setting, and sends this signal to its own, digitally controlled op-amp. Thus, Dragonfly indeed has analog volume control, although it is implemented through the host computer.

After playing once with a borrowed Dragonfly 1.2 I finally got Dragonfly Black 1.5 version. The card feels heavy and solid (well, as heavy and solid a USB flash can be), and produces  pleasant and agreeable sound. There is a USB male connector on one side, a mini-stereo female connector on the opposite end, and a dragonfly cut-out on the top, which shines with different color, depending on the resolution of the digital audio signal. The mini-jack solidly locks the cable, however the USB connection does not feel that secure, because of the weight of the card. After playing once with the card directly inserted into my laptop USB port, I have added to my setup short USB male to USB female adapter. Better safe than sorry.

All Dragonfly cards are built around ESS Sabre DACs. All of them deploy one or another make of asynchronous USB receiver chip.

Manufacturer site: http://www.audioquest.com/dragonfly-series/

3.2.2. FiiO Kunlun E18

In 2016 FiiO Kunlun was a Swiss knife of a card. In the size of iPhone 4 enclosure, the engineers packed a solid volume knob, play/pause and forward/back buttons, which indeed work with Android phones, and also bass boost and volume boost switches that come very handy when playing on a crappy audio system of a small cafe.

The card has two separate outputs  – headphone out, affected by all the controls, and line out, undisturbed by any of the controls. I would routinely use headphone out with bass boost and often volume boost engaged for cafes and small places, and line out for connecting to the house mixer channels. This line out also doubles as the line in, if the card is used simply as an amplifier, bypassing its DAC. Even though it is not very obvious, two inputs of this card, digital and analog, can actually be used together, that is you can connect both your computer and a phone with the performer’s music to the card at the same time, although the analog input is not overly sensitive. There is an additional mode switch in the bottom that allows to use the card either as a computer interface, phone/tablet interface, or an emergency phone charger.

The card comes with a bunch of digital and audio cables, rubber bands, and a nice poach for carrying, all for $130 list price, or as low as $80 when it is on sale.  My only problem with it was the tiny micro-USB connection, which may come lose if you are not careful. Carrying a second USB cable and/or reconditioning it slightly, by bending outwards the two tiny tongues on the male connector when the connection becomes loose, certainly helps.

Manufacturer site: http://www.fiio.net/en/products/20

3.2.3. Beyond 2016: other FiiO sound cards and players

New FiiO DACs models appear every year, but they all share similar design: very handy separate phones and line outs, volume knob and two switches for volume boost and base boost. Among those, there is at least one other DAC, which might be of interest for you, namely FiiO 10k Olympus. This is the second release of the famous original Olympus DAC. This card cannot be used with the phones/tablets, and its design is indeed much better suited for a tabletop. The new 10k sells for $75. The original one can be found on eBay for about $45, which is an incredible bargain.

A word of caution – older FiiO sound cards, such as E10 Olympus or E17 Alpen were built around Wolfson WM8740 chipset. However, a few years ago, FiiO switched to PCM-5102 DAC by TI/BurrBrown. If you support the sentiment of Wolfson being “warmer and more musical” than BurrBrown, you should indeed look for the original E10 Olympus or E17 Alpen in the aftermarket. The new E10k, newest E17k, as well as E18 Kunlun models are all equipped with the BurrBrown DACs. Either older or newer FiiO sound cards are not equipped with asynchronous USB receiver chipsets.

In 2018, the top-selling FiiO portable DAC is Q1 Mark II, with 384 kHz / 32 bit AK4452 DAC, which you might want to consider instead of Kunlun.

In 2019, I was very happy to find out that there is, finally, a soundcard with USB-C, not micro-USB connector from FiiO, namely, K3, which became my current choice for all traveling DJ duties.

Also, take a look at FiiO portable music players, such as FiiO X3. Any of those can double as a USB sound card, or analog headphone amplifier.

All various FiiO products can be found on the manufacturer side: http://fiio.net/en/products.

3.3. Professional Recording Interfaces

The main use of professional recording interfaces is just that – to record the music from microphones straight to the computer, e.g. they are multi-channel analog to digital converters combined with high-quality mike preamps. However, all of them also have digital to analog converters as well, in order for the musicians and sound engineers to produce multi-layered recordings, track by track. These cards are relatively bulky, and quite heavy as well, so what would be the reason of using those for Tango DJing?

Well, first of all, they allow to connect an external microphone, have an additional input for a line source, such as a phone or tablet with the performers music, often come equipped with balanced outputs, always have separate volume controls for the line outs and headphones, or, in short, they are compact digital mixers, which have just enough inputs and outputs for a portable, and completely self-sustained Tango DJ setup.

Also, the recording engineers do not like to talk about the “color of the sound”. All they need from their converters is a very clean, honest sound without any “character” whatsoever. So, if you don’t want either “punchy” or “purring” sound coming out of your card, and you don’t mind lugging around another kilogram or so in your DJ bag, those cards might be for you. In terms of resolution, the reasonably priced ones usually can handle up to 24 bit / 96 kHz, and the more you pay the better resolution you get. Also, they often come in a product line-up, where, with yet another $50 or so increment you can get an additional feature, such as an additional pair of digital channels, balanced outputs, etc.

3.3.1. Focusrite Scarlett Family

Focusrite manufactures a whole line of USB interfaces, well suitable for Tango DJing under Scarlett brand name. All the cards are approximately of the same size, all weight around a kilogram, all enclosed in a solid brushed metal casing of scarlet red color. The sound, as you might expect, is very clean and colorless, like in any other professional audio interface.

The lowest card in the line-up, Scarlett Solo, has one microphone and one line input, both with gain knobs, cute signal/overload indicators, 1/4″ headphones jack with dedicated control, a pair of RCA outs, controlled by oversized volume knob, and sturdy USB-B jack for digital in. This is 2-in / 2-out card. In order to pass the sound to the output, you must engage “Direct Monitor” switch, and in order not to burn some odd microphone, you must disengage “+48V” button. The card sells for $100.

If you want to have balanced out, you can get Scarlett 2i2 instead. This card comes equipped with two combo jacks, instead of one mike / one line combo, which pretty much justifies its price at $130.

If you want a four-channel card instead, in order to use stereo for both FOH and cue, and not to mess with adapters, you might want to look at the next card in the line-up, Scarlett 2i4, for $170. Besides 4 input channels, the card has both balanced (TRS) and unbalanced (RCA) outs for channels 1 and 2, and additional pair of RCA outs for channels 3 and 4.

The nice bonus is that any of the above cards come with two proprietary Focusrite DSP plugins – four band full parametric equalizer, and compressor. I use a different compressor in my DSP chain, but their parametric equalizer won by large margin of any other software model that I have tried before.

When I was looking for a card from this line-up, I definitely wanted an option of balanced outs, but could not care less about four channels, or additional drivers that were required for 2i4, so my choice became Scarlett 2i2 card.

Update 1: in 2017 Focusrite switched to a newer DAC, bringing the resolution up to 24 bit / 192 kHz and added to the package a whole bunch of various digital tools, bringing Scarlett 2i2 to the top of best selling lists in many audio stores. Also, all three above mentioned cards are now class-compliant, e.g. no drivers are required even for 2i4 for either Mac OSX or Linux, and there is an ASIO driver for Windows, as usual.

Update 2: in 2019 Focusrite released Mk3 line. The main difference for DJs is that now the smallest and the lightest Scarlett Solo Mk3 has balanced outs, so there is no need to buy more expensive 2i2 My only complaint about the new release is rather an unwise change from USB-B to USB-C connector on the back of the card.

Manufacturer page for all Scarlett family: https://focusrite.com/scarlett

3.3.2. Steinberg, MOTU, and Roland families

Very similar to the above, Steinberg MT GmbH has its own lineup of the USB recording interfaces. In the ranks of professional audio engineers Steinberg is usually placed above FocusRite, but those are interested, first and most of all, in the quality of the microphone preamps rather than the quality of reproduction. The prices are rather similar: from $100 for UR12 model (equivalent of Scarlett Solo) to $200 for UR242 model (equivalent of Scarlet 2i4). You can check its full line up here: http://www.steinberg.net/en/products/audio_interfaces/ur_series/start.html

Another family of 2×2 and 2×4 interfaces was introduced by MOTU in 2019. The newer release date spells higher resolution, and also cute input and output level indicators on the front panel. The list price for 2×2 card is $170. The full info is here: https://motu.com/products

Between Focusrite, Steinberg and MOTU I would personally go only for Scarlett, because of the additional software coming with it, but otherwise those interfaces are very similar in their feature sets, and I did not have a chance to listen to either Steinberg or MOTU to give you any opinion on their sound characteristics.

However, something much more interested was offered in 2019 by Roland, namely, its newest Rubix family. This is the list of additional features, offered by 2×4 version of the soundcard, with the list price of $200:

1. Choice of stereo or mono playback. Very convenient for those of us, who prefer mono, and there are multiple reasons for such a choice, even though they are beyond the scope of this article.
2. Embedded compressor with three predefined curves – for the instruments, for the voice, and for the limiter, with controllable threshold. If you are in the habit of announcing tandas, connecting your mike to the card, instead of house mixer and engaging the voice setting for the compressor will do wonders with the consistency of the level of your announcements. The Mix knob comes handy to do the announcements during, not after the cortinas, but this knob is the standard feature on all listed above four-channels interfaces.
3. Ground lift switch. This is the ultimate rescue in case of a ground loop, without a need for an additional DI. This feature is available on both 2×2 and 2×4 versions of the interface, and is rather unique to Roland Rubix line. I have not seen it on any other card, even on a Swiss-knife like Sound Devices USB Pre-2 for $900.
4. Up to 192 kHz resolution, which only recently became available on the reasonably-priced professional sound interfaces, for those who is interested.
5. Sturdy and reliable USB-B connector, instead of USB-C found on most of the newest interfaces including Scarlett Mk3 line.

Here is the link to the manufacturer page of Rubix 2×4: https://www.roland.com/ca/products/rubix24/features/

3.3.3. Mackie Onyx Blackjack

Mackie Onyx Blackjack does not come in a product line-up. It is just one card, with two microphone inputs, balanced TRS outs, headphones jack, and familiar USB-B digital input. Even though it does not look very elegant, it certainly has the best ergonomics in its class, all for $100. The card feels as solid as any other Mackie product. On the digital side, this is 2-in / 2-out card. For the recording purposes, if anyone care, it also comes with the most capable (although not  the cleanest) microphone preamps – they go up to +60 dB compared to +50 dB of Steinberg UR and +54 dB of Focusrite Scarlett. This card was recently used by a colleague DJ in a popular local venue, where I regularly play as well, and I was pleasantly surprised by its “beefy” sound, rather unexpected for a professional recording interface.

Manufacturer site: http://mackie.com/products/onyx-blackjack

3.3.4. Apogee One for MAC

For a professional audio interface this 24 bit / 96 kHz, 2-in/2-out sound card lacks in some areas. Namely, the output is a single tiny 1/8″ stereo connector, monitoring can be enabled only via software, it is compatible only with OS X (Mac) and IOS (i-Something), while the price of the least expensive model is $250. Apogee One does offer almost unbelievable +62 dB of crystal-clear gain in the mike preamp, but this is the feature, which is of the least interest to us.

However, if you do DJ from MAC, play your music with a DJ player, such as Traktor, or host your plugins in Audio Hijack, this sound card will provide you with a unique feature, namely, a built-in, very sensitive condenser microphone. In order to use this mike (or an external mike, connected to the card through a breakout cable), you should route the mike output of the card into either an input deck or auxiliary input in your DJ player. Alternatively, you may create an additional input device, and route it straight back to the output device in Audio Hijack. Now, for any DJ announcements you can talk directly to your sound card, with very acceptable weight and size and excellent build quality.

But if you use Windows and/or don’t care about the mike you should look back at FiiO cards for visibly smaller size, weight and price factors as well.

UPDATE 2019: In Mar. 2019 the card stopped working just about two years after the purchase. This is the worst performance of any card that I have used, let alone “premium class”. In Sep. 2019 I have received a report from a colleague DJ that his Apogee One also stopped working after two years use. This sound card is no longer recommended.

3.3.5. Audient ID4

This is a versatile sound interface at the top of the recommended $100 – $200 price range, which comes up in various DJ forums from time to time, and which I finally had a chance to try out… and ended up buying it for myself as well.

There are several features which may put this card on the top of all other offers in professional DAC category:

1. The card is built like a tank, with sturdy aluminum body and large aluminum knobs.
2. The ergonomics is great. All the control elements, which include separate knobs for mike/line and DI gain, output mix, volume encoder, and also mute and ID button, are well-placed on the slanted top of the card, together with a friendly multi-segment  indicator used for input and output level monitoring.
3. Additional audio features include panning the signal, which may come  handy in some odd-designed venue, and also dimming the signal by tapping on the encoder, if you like to announce next tanda while cortina is playing. If you have your own mike, connected to the card, you can use Monitor Mix knob for the same purpose.
4. The card has two headphones jacks – 1/4″ and 1/8″.  The smaller jack allows connection to a DJ cable without the need for any auxiliary adapters, in those odd cases when the mixer is absent, or located far away or even in another room (think Club Fulgor and some other venues in Bs.As.).
5. The unique Id ScrollControl feature that allows to use the volume encoder  as a mouse wheel anywhere on your computer screen, for fine adjustments of your equalizer or other plugins. You enable this feature by pressing the ID button. Even though a single encoder knob cannot replace a full-blown MIDI controller, but it can provide critical tactile control over your EQ and other DAW controls.
6. Rather exotic nowadays, reliable USB-B connector on the back.

This card is both bulkier, heavier and slightly more expensive than all others cards, listed in this section, but if you can live with it – you should certainly give it a try. Compared to the original Focusrite Scarlett 2i2, this card sound is somewhat better defined, and has more “punch” throughout the tonal range, even though the difference is rather small.

4. Afterword

I tried hard to present you with the multitude of the options, not with strict ranking of the various sound cards, available on today’s market for Tango DJs. Even though some of the cards that I presented in this review are, indeed, de facto standards in this or other class, this alone does not mean that a particular card will suite best your personal needs. Find the one that does, and have many happy milongas!

Version 1.13, last updated 2019/11/25