Why use a dac for headphones?

If you’ve ever thought to complain to one of your audiophile friends about your headphones sounding worse on your setup than on theirs, chances are they’d urge you to purchase an external DAC in a most well-meaning manner.

The thing is, there are plenty of DACs out there – some can easily fit into a pocket while others can be quite heftier. And the price varies just as much! Most importantly, as far as you know, none of your non-audiophile friends are using them. So naturally, the question arises:

Is an external DAC necessary for your headphones?

Let’s find out!

First things first, let’s see what a DAC even is.

DAC is an acronym for digital-to-analog converter.

Since all the songs – or audio files of any kind, for that matter – stored on your PC or smartphone are digital (strings of ones and zeros), they need to be converted into analog signals before the driver can interpret them and turn them into sounds that we can hear.

That’s precisely what DACs do – they act as audio signal translators, letting us understand what the source file is trying to tell us.

So, if you were to try and play music without a DAC, the audio source would still be sending out a digital signal, but naturally, you wouldn’t be able to hear it.

In that sense, a DAC is not only necessary but essential in order to listen to any kind of digital music.

As you’ve already picked up by now, we can hear the music we play on our smartphones and PCs even without purchasing a DAC. This is because these devices feature their own built-in DACs. The motherboard of your PC or laptop has one, and your smartphone’s got one as well.

But not all DACs are made equal. So the crux of the issue becomes this:

What can an external DAC offer that an inbuilt one cannot?

The answer is quite a bit, actually!

High-quality audio is not the focus of every device out there.

Many smartphones, especially budget ones, are content with DACs that are just good enough for you to carry out a phone call without any hiccups. In fact, they need such mediocre DACs to keep the price down.

And that’s where external DACs come in – they can get rid of the unwanted artifacts, distortion, and so on caused by subpar built-in DACs.

On the other hand, some built-in DACs can be rather powerful. For example, there are certain high-end motherboards out there that feature DACs so good that an upgrade to an external DAC just wouldn’t be worth the money.

So, if you don’t have any issues with your audio in the first place, chances are you don’t need an external DAC.

At the very least, check to see if your built-in solution is already exceptional so as not to waste money.

However, one reason you may want a DAC, even if you’re content with the audio your smartphone or laptop can generally produce, is if you’re suffering from issues caused by impedance.

Impedance is an often-overlooked headphone spec that’s kind of difficult to explain succinctly.

We’ve had to write a full guide about it just to cover the basics, so read that if you want the full rundown.

In essence, impedance shows you what your headphones are like at resisting the signal from the audio source. This is measured in ohms, with the range for headphones spanning between 8 and 600 ohms.

The lower the impedance, the less resistance the headphones offer, which means you don’t need as strong a signal to use the headphones properly.

Consequently, the higher the charge, the more resistance it offers, which means you need a more powerful signal to adequately use the headphones.

Why is this a problem?

Well, battery-powered devices like smartphones simply cannot generate a strong enough signal to properly feed high-impedance headphones. As a result, if you were to plug a pair of high-impedance headphones into your smartphone, you’d be treated to subpar audio that’s not only quiet but also inconsistent at different frequencies. The same goes for many PCs and laptops.

So, if, for whatever reason, you’ve got a pair of high-impedance headphones that you want to pair with a device that just can’t handle them, you can use an external DAC to fix the issue.

In truth, it’s not the DAC that’s feeding more power into the headphones – that job goes to the amplifier. Most DACs come with their own amps, so that’s how that works out.

As a quick reference, when we say high-impedance headphones, we mean anything with an impedance of over 100 ohms. There are some motherboards out there that can handle even 600 ohms, but unless you’ve got a high-end motherboard, don’t hold out hope for this.

On the other hand, low-impedance devices span the range between 8 and 26 ohms. Anything in this range can be properly used by a battery-powered device since even the battery can produce a strong enough signal to overcome this low resistance.

Then there’s the middle area that’s considered neither low nor high-impedance. Headphones in this range are often called DJ headphones, and whether or not you can run them without an external DAC should be approached on a case-by-case basis.

In most cases, you’d likely need an external DAC for headphones with an impedance over 50, but this depends on your audio source – some battery-powered devices can handle these mid-range impedance ratings better than others.

There’s a lot more to impedance than this, but this should be enough to understand the role it plays in the need for external DACs.

In any case, external DACs do offer an improvement in sound quality; it’s just that the degree to which they help can vary.

For example, external DACs used to be the go-to solution for eliminating jittering and hissing, but nowadays, even the cheapest built-in DACs don’t suffer from these issues.

DACs are also known to positively affect the soundstage of headphones. This makes the music feel more engaging and lifelike. Gamers could also use this to benefit from better surround sound.

For example, the Sennheiser GSX1000 DAC not only improves the audio quality over a regular old internal DAC, but it’s also able to even exceed some true surround sound headphones.

There are other small quality-of-life improvements that external DACs bring to the table, but it’s paramount to understand that the DAC, external or otherwise, can’t do all the heavy lifting by itself.

The DAC is just one variable in the equations towards higher quality audio, but it doesn’t offer much if you neglect the other variables. And, for the most part, the other variables boil down to the headphones and the audio format.

We’ve got plenty of great headphones and earbuds reviews here – from wired models to wireless and even true wireless ones – so check them out if you’re in need of a great new pair of headphones or earbuds.

In any case, we’d argue that good headphones and an okay integrated DAC offer a better listening experience than a great DAC with subpar headphones.

However, not even the best headphones and the best DAC will help if you simply listen to lossy audio formats.

There are many lossless formats out there, like FLAC, for example, that are capable of reproducing music exactly as it was recorded. But lossy formats like MP3 simply aren’t as high-quality and can introduce all kinds of distortion problems.

If MP3 is a-okay to you – which is perfectly fine, as not everyone has the same kinds of expectations from their music – then you’re likely not the kind of person who needs an external DAC except in the case of impedance mismatch.

Alternatively, even if you want to ensure the best possible listening experience, you should first make sure to use lossless audio files and procure a proper headset before worrying about an external DAC.

It’s the last step you should make in your quest for awesome audio.

In conclusion: Is an external DAC necessary for your headphones?

In most cases, the answer is no.

Built into the likes of computers, tablets and smartphones, a DAC is a fundamental key to unlocking the convenience of digital music. It converts the countless reams of digital information into analogue signals that are intelligible to the likes of speakers and headphones – and the human ear. They all need an analogue waveform. Without a DAC, your digital music collection is nothing but a sizeable collection of “0s and 1s” (more on that shortly) that makes sense only within the digital domain. In short, DACs play a large part in making digital music worthwhile.

Therefore, any device that acts as a source of digital sound – be it a CD or Blu-ray player, digital TV box or games console, or phone or portable music player – will need a DAC – either integrated or connected – to convert its digital audio to analogue before it is output.

The biggest problem is the DAC circuits used in many devices are just not efficient enough to accurately convert digital to analogue and thus do justice to the original recording. And that's why a DAC upgrade can be the simplest way to improve your digital music and really get the most from your system, whatever your set-up.

The sounds we hear on a day-to-day basis – traffic, instruments, that baby screaming on your otherwise peaceful commute – are transmitted in soundwaves, which travel through the air to our ears in a continuously varying analogue signal.

Analogue recordings were stored on the likes of shellac (and later, vinyl) discs, and later still magnetic cassette tapes, but the fragility and unwanted noise of these formats made way for something new. The CD was born, kickstarting the digital audio revolution in the process.

Digital audio takes a very different approach to that of analogue. Digital music files are usually found in the form of Pulse Code Modulation (PCM), and are created by measuring the amplitude of the analogue music signal at regular intervals.

The value of the amplitude is represented as a binary number (comprised of 1s and 0s) and the length of this number is often referred to as bit depth. The timing of the measurement intervals is called the sampling rate.

When recording a standard CD, say, a sample is taken 44,100 times per second. Each of these samples is measured to an accuracy of 16 bits, storing the results in a 16-digit binary format.

Record a high-resolution track, on the other hand, and you’ll take a step up to 24 bits, with a sample taken as often as 192,000 times per second.

Digital audio data can be stored in a variety of sample rates, bit depths, encoding and compression formats – but no matter how it’s done, it is the DAC’s job to make sense of it all, translating it as accurately as possible from its binary format to return it as close to the original analogue recording as it can.

While it’s true that just about every piece of digital kit features a DAC, it’s just as true that not all DACs are created equal. For starters, they might not support all file data rates.

Poor converters can introduce unwanted noise during playback due to poorly designed circuitry, not to mention add extra distortion due to jitter. (Jitter is best defined as digital timing errors. The precise timing of a digital music stream is vital to high performance, and if that isn’t done properly - usually because of poorly designed digital-clock circuitry - performance suffers.)

Jitter problems can arise every time a digital signal has to travel around a circuit board – and it’s particularly troublesome when the signal is transferred between devices. In recent years we’ve seen the rise of the asynchronous DAC, which takes over timing duties from any computer it may be connected to for just this reason.

The digital clocks found in dedicated hi-fi DACs tend to be more accurate than those used in the average PC, so usually the conversion process will be performed more faithfully.

Of course, to get the most from a DAC you need to start out with good source material – don’t expect miracles if all you’re throwing at a converter is 128kbps MP3s. In fact, better decoding of such a compressed signal can make any sonic shortcomings more obvious.

You’ll hear optimum results with CD-quality content and above, which is best stored in FLAC, WAV or ALAC (Mac) lossless PCM formats, or alternatively DSD if you prefer...

DSD, or Direct Stream Digital, is an alternative to PCM and was originally conceived for Super Audio CD (SACDs) – a format championed by Sony and Philips in the late ‘90s and into the ’00s.

It’s a much more niche format, differing from PCM by offering a bit depth of just one, but much higher sampling rates – commonly DSD64 at 2.8 MHz and DSD128 at 5.6 MHz.

The arguments as to which encoding system is better continue to rumble on. Suffice to say if you’re someone firmly settled in the DSD camp, it’s worth checking the DAC you’re considering supports it – most, but not all, do.

DACs come in all shapes and sizes and offer varying levels of input options and functionality, so you’ll need to think about how you want to use it, not to mention the budget you have set aside.

Compact USB DACs offer portability and convenience at a reasonable price. They vary from USB sticks, such as the Audioquest DragonFly Red and Cobalt, that plug straight into a laptop (or to a phone via a converter dongle), to wireless DACs like the iFi GO Blu that can connect to a source (though not your headphones) via Bluetooth.

Some draw the power from your computer or phone, so there’s no need for an extra power source, and they largely keep connections simple, with just a headphone socket and possibly a line-level output for hooking up to powered speakers or a hi-fi system.

If you need more connectivity and are not concerned about taking your DAC around with you, a desktop unit like the Chord Mojo 2 or Cambridge Audio DacMagic 200M might be more suitable. These are usually bigger and require their own power source, but often offer several additional digital or analogue audio inputs alongside a USB input for connecting to your computer. Some, like the iFi Zen DAC V2, can be either USB or mains powered.

Keep an eye out for a DAC with a headphone amp if you want to use headphones, as most but not all DACs offer this as an option – the Award-winning Chord Qutest, for instance, is a standalone DAC without any headphone features, designed to slip into a system between a digital source and amplifier to enhance performance.

Finally, there are the DACs that are born to work as part of a bigger home audio system. These will usually have even more inputs – particularly more niche sockets such as AES/EBU – and potentially more features too, including perhaps a volume control so they can also be used as a pre-amp. They'll support the full range of high-resolution music formats or have Bluetooth connectivity for streaming wirelessly from your smartphone or tablet, though both of these offerings are increasingly offered by portable and desktop units these days too. These home DACs tend to be at the higher end of the market so should deliver higher performance, too.

These can range from the sensible (the Audiolab M-DAC+, say) to the extravagant (the Chord DAVE) or, if money really is no object, the Nagra HD DAC/MPS.

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There are many audio products on the market that promise to improve the quality of your sound. But great sound comes from more than just a great set of quality headphones; using an external Digital-to-Analog Converter (DAC) is an excellent way to enhance your sound and have your headphones working to their full capacity.

Take note: For the sake of brevity, we are assuming that the external DAC comes bundled with an amplifier (amp).

A DAC system is fairly self-explanatory. Songs which are stored in digital form, like MP3s and CDs, are represented in digital signals. This handy device takes the digital audio data and translates it into an analog audio signal. That processed signal is then sent to a headphone amp, which elevates the signal to an audible level on a headphone.

As such, a headphone DAC offers a powerful, but dedicated, component to the sound equation.

You may be surprised to find that many electronic devices already include a built-in DAC and amp. They can exist in either in the form of the speaker output or headphone audio port. Without them, your music would remain a series of 0s and 1s never to be heard by the human ear.

But if that is the case, why do you need an external headphone DAC for?

Simply put, the quality of the music you hear is determined by the precision of your DAC converter. The aim of any sound system is to preserve and recreate, as much as possible, the true sound of the studio recording to your ear.

Whether you should invest in an external DAC depends firstly on the specifics of your existing gears. For the average listener, the quality of an internal DAC is already acceptable.

For audiophiles, however, the DAC circuits used in many devices just don’t do the original recording justice, and they desire an upgraded, “cleaner” listening experience.Hence, they upgrade to an external DAC to bypass the inferior built-in audio circuitry.

An external DAC bypasses the internal DAC and can fix many problems associated with inferior devices.

These issues include:

Jitter occurs due to digital timing errors. If the clock in your music device and the internal DAC aren’t in sync, then the audio quality may sound slightly off. A premium DAC achieves a more precise timing, which is vital for digital music streaming.

Background hiss can be extremely frustrating during the quieter segments of your music. Using an upgraded DAC can clean up the signal quickly and easily, eliminating the noise at its source.

While some DACs may not support all file data rates, an external DAC can. This allows more versatility, and so an external DAC may be the best choice in this situation.

Inferior converters can add unwanted noise during playback because of poorly designed setups. Upgrading to an external version is a welcome remedy, which can also eliminate any interference produced by your sound card.

Headphones with high impedance or resistance require a high voltage output from your device. Devices with poor amplifiers do not have enough power to produce high audio level, resulting in low volume. One method of increasing the overall volume of your music is by using an external DAC, as many are built with amplifiers.

Music aficionados seek dynamic sound quality and fidelity. A superior external DAC can enhance your tunes with improved clarity and marked detail, and generally, outperform inbuilt DACs in many areas.

I often find questions in forums like this:

There are various elements, other than the DAC and amp, which can influence playback quality:

To get the optimal effect from your DAC and audio system, you need to start out with good source material. The best results will always come from CD-quality sound and above. My suggestion would be to stick to “lossless” audio formats such as FLAC, WAV, ALAC or DSD formats.

On the other hand, we have the “lossy audio format” such as MP3 and MP4. In comparison to “lossless” audio, the compression process can add all kinds of distortion to your music. If you only listen to “lossy audio”, even if you upgrade to an expensive DAC, do not expect to get any extreme sound upgrade.

Bear in mind: Rubbish in, rubbish out.

The number of details that you can pick up from your music depends on your headphone. Even if the DAC can accurately recreate the recorded analog signals, the headphone have the final say in how the sound translates into your ear.

A headphone with low-end dynamic driver will not sound the same as a headphone with quality drivers.

An external DAC will also do little to affect the frequency response that you get out of the headphones. For example, a headphone with v-shaped sound signature have recessed mids and emphasis on the lows and treble. In this case, there is nothing an external DAC can do to affect that.

DACs come in many different sizes and offer a range of functionality. For example, some are ideal for headphones, while other types only work with stereo systems. Of course, DACs all come with different price tags, and therefore the one you settle on will depend ultimately upon your requirements and budget.

To wrap it up, let’s answer the over-arching question: