Expert review and test of the FiiO Q1 MkII Portable DAC/Headphone Amplifier by Australian Hi-Fi Magazine. Free pdf download included.

I had been planning to review the FiiO Q1 portable DAC and headphone amplifier, but before quite getting to it, the Chinese firm launched a successor. The FiiO Q1 Mark II is a huge upgrade over the original model. The old unit was a PCM-only device, limited to USB Audio Class 1.0 compatibility. That means it topped out at 24 bit, 96kHz sampling. The new one? It’ll handle just about any digital audio standard you’re likely—or even unlikely—to have on your notebook computer, tablet or phone.

The Equipment
To be clear, even though the FiiO Q1 Mark II handles true, grown-up audiophile signals, this is a portable DAC and headphone amplifier. Very portable. It weighs a smidgeon over 100 grams, and is only 100mm long on the longest dimension. The clear intention is to allow you to enjoy high quality audio while you’re on the road.

And despite its considerable capabilities and (as we’ll see) excellent performance, it only costs $150. Audiophile quality is now within reach of most of us.

The FiiO Q1 Mark II is a DAC and a headphone amplifier that is compatible with Windows and Mac computers, and with Android and iOS tablets and phones. I imagine it’s also compatible with Linux devices, although I haven’t tested that. 

You can use its headphone amplifier functionality with analogue sources as well.
In addition, the device has a built-in 1800mAh rechargeable Lithium Ion battery, allowing it to power its own functions when used with certain portable devices. If you plug the unit into a computer, it will draw power from the computer to charge up its battery. But if you plug it into an iPhone, it will recognise the connection and use its own internal power, avoiding a power draw on the phone. It’s not clear what happens with an Android phone, although I expect it would be like the iPhone. FiiO says that with a full charge, the internal battery will last for 20 hours with analogue inputs and 10 hours when it’s used as a DAC.

Typically you will use the digital input to feed music to the FiiO Q1 Mark II. This is via a Micro-B USB connection on the bottom of the FiiO Q1 Mark II. Included with the unit is a standard USB Type-A to Micro-B USB cable, suitable for connecting the unit to either a Windows or Mac computer. The unit can also be charged up using this cable (whether from a computer or a standard USB power supply). Also included is a short Apple Lightning to Micro-B USB cable. This is to allow use with an iPhone or an iPad. The unit will also work with Android devices which support the ‘On-The-Go’ standard for their connectors. No cable is supplied for this application.

Also on the bottom are two small slide switches. One is a bass booster, the function of which needs no further description. The other is a gain switch with high and low settings.
All the other stuff is at the other end. There are three sockets on that end, a combination rotary volume control and power switch, and two LEDs. One of the sockets is for a standard 3.5mm headphone jack. Next to that is a 2.5mm, 4-pole socket for balanced headphones. The latter is rated to support headphones with impedances from 16 to 150Ω. No impedance specification is given for the standard output, but it is rated as being capable of delivering more than 75mW into 32Ω loads. The balanced output is rated at 220mW into the same load.

Next to the balanced output is another 3.5mm socket. This acts as both line input and line output. I am not certain how it knows which function it should adopt. I had assumed that it switches to input function when headphones are plugged in, but just now I tested that and found that it’s happy to deliver to both headphone and line output at the same time. 
Perhaps it defaults to line input when no signal is being provided via the Micro-B USB socket.

The blue LED is simply a power indicator. The green one illuminates only when a Direct Stream Digital signal is being received. That’s a very useful function. Getting source equipment and software to stream DSD to an external DAC, rather than convert it to PCM, can be tricky. This LED gives the user confidence that they have it right (or informs them that they’re going to have to play with their settings some more).

Inside, the unit uses an AKM AK4452 DAC chip. This is a high-resolution DAC with support for PCM signals from 8kHz to 768kHz sampling and 32-bits of resolution, and Direct Stream Digital to 5.6MHz. It uses 256× oversampling and has selectable filter characteristics. 

The signal-to-noise ratio is specified at 115dB, and THD plus noise at –107dB.
The headphone amplifier chip is the OPA926, apparently from Texas Instruments. I couldn’t find any spec sheets for this at the TI website. The line output chip is the OPA1662, one of TI’s ‘ultralow distortion’ op-amps.

Installation
As I’ve previously mentioned, since early 2017 Windows has belatedly supported USB Audio Class 2, which pushes things beyond 96kHz, 24 bits. So when I plugged the FiiO Q1 MkII into a Windows computer, it was recognised and started working almost straight away.

Windows Audio Device manager gave a list of compatible output formats, from 16-bits and 44.1kHz to 32-bits and 384kHz, with all the 44.1kHz and 48kHz multiples along the way.
So I ducked over the Foobar 2000 to play some real music, and immediately selected WASAPI (FiiO Q1), and tried playing back some unremarkable CD-standard FLAC… at which point Foobar informed me that this was an ‘Unsupported stream format: 44100Hz/24-bit/2-channels’. I switched the output to 16-bits and it worked.

So I tried some 192kHz, 24-bit music, and it produced an output that sounded like it was being transmitted through a bamboo rod, rattling against a diaphragm. I switched back to 24-bits, and got a similar failure message. So, unless you’re prepared to accept Windows doing its stuff to the audio, you’re going to have to go to the FiiO website (www.fiio.net) and download some drivers. You’ll need them anyway, because you’ll want ASIO support for DSD.

The driver was easy enough to find on the FiiO website, but you will need to download some unpacking software which can handle RAR files, rather than the far more common ZIP files. 

Confusingly, there were a couple of different executable files to choose from on the FiiO site. I picked one more or less at random, and it installed the relevant drivers. Soon I had DSD and high-resolution PCM up to 384kHz working fine from my Windows computer.

Such troubles weren’t needed for iPhones and Macs. With these it was a straightforward plug-and-play. Likewise for Android phones and devices, although you’ll need to supply your own cable. As it happens I have both Micro-B USB to Micro-B USB, and Micro-B USB to USB Type-C cables, so I was able to test it on several Android devices successfully. I used the USB Audio Player PRO app on Android devices for high-resolution and DSD. For iOS devices I used the Onkyo HF Player. The paid version of this can stream high-resolution audio, including DSD, to external DACs.

I also tried an iPod Nano of the last generation before they were discontinued. I couldn’t get any sound out of that, but they’ve always been pretty iffy at working with external DACs.

Subjective Performance
So, first things first: yes, this DAC worked with all the PCM and DSD files I had available. That included high-resolution FLAC music at up to 352.4kHz and 24-bits (the software in your device handles the decoding to PCM, the FiiO does the DAC duties), and Direct Stream Digital at standard, double and quad speeds (otherwise known as DSD64, DSD128 and DSD256). The various pieces of player software inform me both of the source file format and what they’re actually delivering to the DAC, so I know that there was no PCM conversion with DSD, and this was confirmed by the indicator light on the unit.

I had no balanced headphones available so I instead switched around between using Oppo PM-3 headphones, twenty-year-old Sennheiser HD 535 headphones (which I still love) and Blue Lola headphones. The first and last are closed back. The Sennheisers are open back. They are also rather inefficient, and have an impedance of 150Ω. If there are output level problems, these headphones will disclose it.

But they didn’t. I was able to play everything at any volume level I wanted, even uncomfortably high levels, with these headphones. You will need strange headphones indeed to run out of oomph with the FiiO Q1 Mk II DAC.

As I’m writing this, I am listening to music recorded nearly six decades ago: So What from ‘Kind of Blue’ by Miles Davis. The format is DSD64—this recording has been out on SACD for many years since Sony has managed to convince itself that DSD is some kind of archival format. If I recall correctly, it was recorded on three-track analogue tape. The tape hiss dates it a little—this being pre-Dolby—but there is a lively, uncompressed feeling to the recording. That cymbal, relentlessly sounding at 45 degrees to the right of straight-ahead, the drums, the guitar… all are gorgeously layered in a space that exhibits remarkable depth… even though I am listening through headphones. The music is on a 256GB microSD card plugged into my computer. 

Foobar 2000 with suitable plug-ins is feeding this to the FiiO Q1 Mk II DAC directly in DSD format. That card doesn’t have any super high-resolution DSD on it, so I’ve just switched over to my Google Pixel 2 XL phone. USB Audio Player PRO is streaming some DSD256 music from the NAS server on my network straight to this DAC, which is decoding it beautifully.

The sound is clean, clear and, when using the Sennheiser headphones, airy and open.
But I did most of my listening to music encoded to the CD standard 44.1kHz, 16-bit standard for the obvious reason that that is how most music comes. Holly Cole’s album ‘Temptation’ was richly handled, with powerful bass, yet fine control on such material as Train Song. Even on the HD 535 headphones the bass was full, but with the Blue Lola headphones it was provided with a near-subwoofer-like quality.


Yet the subtleties in her voice remained evident. A little tape hiss was present in the recording, easily heard. The ring of chimes bounced across an internal sound stage with subtlety and beauty.

Objective Performance
Even though the little volume control turns smoothly, without indentations, it appears to operate digitally. From less than half a volt output up to the full 1.51-volts from the headphone output, each step was 0.5dB, (except for the 4th highest step, which was a full decibel). Below that each step was one decibel, except for the 1.5dB jump between 0.448 and 0.375 volts output. I have no idea why there would be those two discrepancies. In practice, I didn’t notice them.

The maximum line output level for a digital input signal consisting of various frequencies of sine waves, modulated to peak at 0dBFS, was 1.58 volts RMS. That’s a little less that than from a standard CD player, but not much less; only two decibels. Note: the line output is subject to unit’s own volume control. There is no fixed output setting. That was with the ‘Gain’ control set to ‘high’. The output voltage was halved with the low gain setting. There are few headphones that this unit won’t drive comfortably.

I did all my listening and testing with the line and standard headphone output, not the balanced output. The headphone output drove 300Ω loads at the maximum output setting without clipping, and produced 1.5 volts. That works out to 7.6mV, and 8.8dB above the (1mW) sensitivity rating of any high-impedance headphones you’re using.With a 16Ω load the output from the full scale sine waves clipped a little at the two highest volume settings, but all was fine at 1.2 volts output. That translates to 90mW, or 19.6dB above the headphone sensitivity ratings, so given that most low-impedance headphones and earphones are rated at well above 100dBSPL for 1mW input, thunderous levels are clearly available.

I calculated the internal impedance of the headphone output to be less than 2.2Ω, so even with low-impedance headphones with which the impedance varies by frequency, the affect on the response should be minimal. With 44.1kHz/16-bit inputs, the frequency response is even to just on 20kHz and drops away sharply above that. Clearly FiiO uses one of the sharp anti-aliasing filters, rather than a slow one, in the DAC chip.

For 96kHz inputs, the frequency response was maintained out to 43kHz before cutting off sharply. With 192kHz inputs, the frequency response of my measuring rig was at least as much the limiting factor, but adjusting for that ADC’s effect, the frequency response of the FiiO Q1 Mk2 was –2dB at 63kHz and –3dB at 75kHz. Some noise delivered to the DAC via the USB socket breaks through into the analogue output. Using a 0dBFS 1kHz sine wave, output via the headphone socket into a high impedance load at max. volume, the noise floor was at –132dB or better for most of the audible band, with a small bump to –129dB around 7kHz. 

That’s when the Windows computer was running from its battery. When the computer was plugged into power, the noise floor below 1kHz hovered slightly above –123dB, with what at first glance look like mains frequency spikes reaching up to –105dB. I say ‘at first glance’ because when you check the spikes, you find that they are at 60Hz and its multiples, not the expected 50Hz. I guarantee I was in Australia when doing this measurement! There’s also a fair bit of spurious noise above 1kHz. Note: none of that was audible. The spikes you see in both noise traces at 2kHz, 3kHz and 4kHz are distortion products. They look bad, but in fact the 2kHz spike is at –90dB, which is 0.003%, the 3kHz spike is at 0.0009%, while the 4kHz spike is at 0.0004%. Add them up together any way you like, and you’ll see that THD is well under 0.005%.

Conclusion
The FiiO Q1 Mark II should not be thought of as an upgrade to the previous model. It is totally different in design and signal handling. The only real commonality is the excellent portability—‘way smaller than any smart phone—and the built-in battery. What it does do is challenge the performance and signal versatility of audiophile DACs costing an order of magnitude more. #  Stephen Dawson