I don't normally do reviews, but sometimes you find a product that just deserves a positive review.

Before I get into the review - or plug may be a better description - I want to give my opinion (everyone has one) on some claims made in the audio industry.

Choosing a USB DAC Headphone Amplifier

Diminishing returns

From my own research - once subjective claims are removed from the mix - I found there there are some significant diminishing returns in this area - that is, don't expect the increase in performance (if any) to be proportional to the amount you spend - keep this in mind when shopping for audio gear - there are a lot of very expensive products that while they often look fantastic, and seem to contain awe inspiring components, their increase in performance is usually only via the placebo effect. Be a sceptic, and don't waste enormous amounts of money based on anecdotal subjective claims regardless of the number of followers - the audio world can be like a battle of religions with many followers.

Huge range

These days there is an enormous range of USB DAC Headphone amplifiers and what ever other combination of hardware you want to mix in. These range from as low as US$40 to many $1000's.. If you're like most online shoppers, you'll use eBay as a starting place for your USB DAC shopping - there are a lot of choices, so many it takes some work to understand the differences.

DACS, bits, hertz, my head hurts!

So let's go through what I have learnt in this area, I want to break this down so it's simple for you to decide what you really need or can and will use.

Different DACs can process different signal combinations. Common ones are:

• 16 bit 48 KHz
• 24 bit 96 KHz
• 24 bit 192 KHz

If your source music is from CD or tracks ripped from CD to mp3, flac, wav, etc then this source audio is 16 bit 44 KHz, such, a device that can do 16 bit 48 KHz will be sufficient - there is no benefit of having a larger bit depth or higher sampling frequency here.

If you have sources that are 24 bit 96/192 KHz then you may want to put extra consideration into the DAC capabilities.

Typically devices that support 24 bit 96/192KHz over USB require additional drivers - this might be an issue if you want portability and ease of installation.

Whereas, devices that support 16 bit 48Khz over USB typically don't require additional drivers.

24 bit 96Khz is usually available via optical or coaxial SPDIF connectivity.

Amplifier Circuit Type

There are many types of amplifier circuits, valve, mosfet, opamp, etc - the most common in USB DAC Headphone Amps are OpAmps.

OpAmps are a good choice here as they offer very low distortion, have little colouration on the output signal are cheap and are often simple to replace and test various types to suit your taste.

The Aune mini USB DAC

With that out of the way, let's look at the Aune.

If you're in the market for a USB DAC and Headphone amplifier the Aune Mini USB DAC Headphone amplifier is an excellent choice.

I purchased mine directly from the manufacturer's eBay store which I highly recommend as their service is excellent - their store representative Candy is very helpful and responds very quickly to email - usually within minutes. I have no affiliation with these guys, I just like their products and service.

Here is a picture of mine:

As you can see the front panel is a solid 8mm thick piece of aluminium, is well finished and has aune engraved (CNC machined) on it.

The components and build quality are excellent for this price range, I was very surprised when I opened mine:

As you can see, it contains quality components and is well constructed.

The underside again shows quality construction, no dry dodgy solder joints (I can't say the same for some other cheap Chinese ones that I own):

The Aune specifications:

• Originated from the DIY project HIFIDIY.NET Mini USB DAC
• Compatible with Windows XP/Vista/7 & Mac OS X 10.x and Linux (most variants)
• Can be used as a DAC or headphone amp
• OPA chip: BB OPA2134
• Headphone AMP: Burr-Brown OPA2604+TIP41C*2+TIP42C*2 (Pull and push)
• Digital Coaxial/USB input, RCAx2/6.35mm stereo analog output
• Headphone amplifier built-in (TIP41C*2+TIP42C*2 (Pull and push) )
• USB controller chip BB PCM2707
• DIR chip -- TI DIR9001
• Main DAC chip -- Burr-Brown PCM1793:
  - 24bit/192kHz Sampling Advanced Segment Audio Stereo DAC
  - Dynamic Range: 113 dB and THD+N: 0.001%
  - 8x Oversampling Digital Filter (from Official data-sheet)

The Aune supports 16 bit 48 KHz over USB and up to 24 bit 192KHz over SPDIF so you have the portability to play 16 bit 44 KHz sources and the SPDIF available if you need the higher source input.

Technical Note

Unlike most USB DACS, the Aune uses the PCM2707 as a USB receiver only, it then passes the received data to the PCM1793 DAC via i2s for A/D conversion - the PCM1793 has a reputation as a higher quality DAC than is commonly used and includes 8x oversampling.

Now on to the performance

I'm using my Aune with a pair of AKG K702 headphones, the Aune has no problems driving the K702s and sounds great. It is very detailed, lots of separation and has a fantastic sound stage.

I won't go into any more detail trying to describe my interpretation of the sound in 'audiophile speak'. I don't consider myself an audiophile and prefer to judge things by their performance and less by their look and status or reputation - let's try and keep the placebo effect well away from our judgement.

Conclusion

My Aune is my favourite headphone amp, it's very versatile, attractive, cheap and a solid performer. You really can't go wrong with this little amp, it's excellent value for money! As I said before, you can purchase these directly from the manufacturer's eBay store where you're sure to get great service and prompt registered delivery.