Questyle QP1R
The Questyle QP1R portable music player in many ways similar to other players of the genre, but is in one way very different from many of the others. Let’s get right into this very attractive, very high fidelity, music player.
 
Equipment
First, here’s what’s different about it. The others tend to be high fidelity equivalents of an iPod touch. The Questyle QP1R is more the high fidelity equivalent of an iPod Classic. Well, a solid-state iPod Classic. Devices like the Astell&Kern AK380 and the Fiio X7 have, at their operational hearts, an Android operating system. They have touch screens. You scroll and select things as you would with a smartphone. As an iPod touch is like an iPhone without the phone functions, they are like an Android phone without the phone functions. Super high quality Android devices, to be sure, with their own high-end DACs and headphone amplifiers, but you get the idea.
 
Questyle QP1RThe Questyle QP1R has a display screen, but it’s not a touch screen. Instead it has a ring which you can rotate (physically, unlike the touch-sensitive one on an iPod classic) with a selection button in the middle. You see the iPod classic parallel?
 
But this is only for navigating the menus and music lists, not for changing the volume. At the top is a quite substantial volume control knob — with a gentle but easily perceptible click for each step — while on the side is a power key. The volume knob is largely protected from accidental knocks by extensions of the body on two sides of it. There are also four touch-sensitive spots on the front around the right: home key, return and left and right skip.
 
The display has a 60mm diameter and 400 × 360 pixels of resolution for displaying menus, track information and cover art. The art is spread to fill the display, so square album covers embedded in tracks will be a little horizontally stretched.
 
Lurking within the unit there would not seem to be the slightest hint of Android nor any other off-the-shelf operating system. This device appears to have been designed and built purely as a music player, with no other function, nor any need for any other function.
 
It comes with 32GB of internal storage, and two microSD card slots, each capable of supporting cards up to 128GB. That’s a nominal capacity of 288GB — say, 500-odd CDs uncompressed, or perhaps 800-900 in FLAC format. Or around 4000 albums’ worth of 192kbps VBR MP3 music if for some reason you’re going for quantity rather than quality.
 
Flip it the other way, go for quality rather than quantity and you’ll fit some 150 to 200 albums in DSD64 format (half that for DSD128, also supported). About the same for 24-bit 192kHz PCM music in FLAC format.
 
The figures above are just to give a sense of the capacity. Of course, you’ll likely have your music collection in a mixture of formats. In addition to the already mentioned formats the Questyle supports ALAC (i.e. Apple Lossless), AAC, ADPCM, LPCM, APE, AIFF, WAV, OGG, WMA and WMA Lossless. DSD support includes both DSF and DFF formats.
 
The device is built by Foxconn (which manufactures Apple products) and is based on a machined aluminium chassis. The metal work is finished in a very rich-looking bronze-gold colour, as is the control ring, while the main part of the front and back feature a black glass look.
 
The DAC employed is the Cirrus Logic CS4398, used in a number of devices. However this feeds an amplifier designed and built around the university work of Questyle’s founder and CEO, Wang Fengshuo. This is a pure Class-A current mode amplifier, offering extremely wide bandwidth and low transient intermodulation distortion. An output impedance of just 0.15 ohms means that even with low impedance headphones (models down to eight ohms are supported), variations in their internal impedance for different frequencies will have no effect on performance.
 
Questyle QP1R
 
There are three gain settings for the headphone output, so you can match the unit to the requirements of your own headphones. Questyle rates the output at up to 12 milliwatts into a 300-ohm load, 40mW into 32-ohm loads and 16.3mW into 16-ohm loads.
 
There are separate line-level and headphone outputs, and the line-level output can also deliver optical digital audio. Charging is via a micro-B USB socket at the bottom. You also use this to plug into your computer for loading music. The built-in lithium-ion battery is rated at 8 to 10 hours of life and has a charging time of eight hours via computer, four hours if using a two-amp USB power adaptor.
 
The unit is provided with a cloth pouch and transparent rings that can be placed over the selector ring to protect its surface, plus a 3.5mm to 3.5mm connection cable, a 3.5mm to optical digital audio adaptor and a USB-to-micro-B USB cable. There are further optional accessories available, like the luxurious leather case shown opposite.
 
Questyle QP1RThere are a couple of small troublesome design elements. Both the headphone and line output sockets are indented by a couple of millimetres into the body of the unit, with a circular cut-out around the socket. The one around the headphone socket is quite large — just over 11mm — but the one around the line output is only a little over 7.5mm in diameter, which prevented either of our normal adaptor cables to insert fully. (Yes, a nice 3.5mm to 3.5mm cable is bundled, but we wanted 3.5mm to stereo RCA.) In the end a sharp knife was applied to the plastic of one adaptor so that it could seat properly and deliver the signal. At the other end of the unit, the USB micro-B socket is also inset, again with a slightly undersized cutout. The supplied cable fits, but none of three others did.
 
Performance
Loading up the unit with music is very simple. When you plug it into your computer (it works with both Windows and Mac) it appears as one, two or three removable drives (each SD card appears as separate storage). Then you just drag your music from your computer onto one or other of the drives and wait while it transfers. It’s best to allow a few hours if you want to fill up all  that 288GB of capacity! 
 
How the music is organised into folders seems to have no effect, but one tip: make sure you have a sensible file-naming structure for your music... starting with track number for each file. The unit reads the ID3 tags, including cover art, from within the file, but it doesn’t pay any attention to the track number, so the music will be presented in file name order. If you like your albums to play through by original order, I’d suggest a ‘[Track number] - [Track title].EXT’ construction.
 
Also you need to navigate primarily by Album. If you go in via ‘Artist’, you’re going to have, for example, all of Primus’ track 1s from all their albums starting the list, in alphabetical order, then all of their track 2s and so on. The ordering does take account of numbers, so ‘Track 9’ will be followed by ‘Track 10’.
 
Questyle QP1RThe unit must index the music. This can be set to auto or manual. Auto does it automatically whenever you load new tracks onto the unit. The routines seem to be a little primitive, doing a full re-index whenever anything changes rather than only examining the new items, but at least that ensures that the system won’t inadvertently become confused. Even if you leave it on Auto, you can slip into the set-up menu at any time and do a reindex. It only took a couple of minutes for the thousand or so tracks we loaded on the system’s internal storage and a 32GB microSD card.
 
Another setting within the menu allows for the line output to be either ‘Variable’ (i.e. under the control of the volume knob) or ‘Maximum’. The latter turned out to deliver 1.69V RMS with a full-scale sine wave — which wasn’t maximum at all because ‘Variable’ with the volume turned up to the max out produced 2.38V RMS.
 
The ‘Gain’ setting of Low, Medium and High applies only to the headphone output, with a 6dB effect between each level. The amount of adjustment provided per click by the level control varied across the full range. Down near the extreme bottom (around 5 on the scale of 60) the adjustment was 4.5dB per click. In the middle of the range it was around 1dB per click, while at the top (59 to 60 out of 60) it was just over 0.5dB per click.
 
One final practical matter: if you have headphones with in-line pause/skip keys, they will have no effect with this unit. The centre button on the unit’s face acts as play/pause, and only works if the unit is awake. You can set this key to wake the unit, so it two presses pause the music. The volume control still worked throughout.
 
The sound produced by the Questyle QP1R was simply glorious. With some utilitarian low impedance earbuds, it was clear that the unit could drive them to any level that you may desire. We listened mainly using Oppo planar magnetic headphones, but since these are relatively impervious to problems caused by high impedance outputs, also a pair of lower-cost Sony units which vary in their impedance across frequency. As expected, the latter remained balanced, supporting the claim of a low internal impedance, but their normally somewhat overfull bass seemed a touch more restrained than usual. It might not have been reduced output, though, so much as simply being tighter, since a low internal impedance allows the amplifier to exert more control over the driver.
 
A present favourite is Rickie Lee Jones’ 2000 album ‘It’s Like This’ delivered as DSD64. Via the Questyle/Oppo combination Jones’ unique voice was delivered with superb intimacy, and the whole of the music with detail and great separation, while at the same time there was an appropriate distance, reducing the sound-in-brain effect sometimes inherent in personal audio. The chime on ‘Show Biz Kids’ above her voice and the bass under it were delivered in a manner that would be indistinguishable from any high-end competently implemented (which isn’t always the same thing) headphone amplifier. I used the unit a fair bit as a source via the line output into my main stereo system, and it delivered a similar level of high performance.
 
In general scrolling through long lists was reasonably fast. The touch-sensitive arrow keys jump through a page at a time and can skip back from A to Z, halving the time for getting through a list. Sometimes the scroll wheel would jump the selection unpredictably, but in general it worked well.
 
Questyle QP1R
Measurements
With 192kHz and DSD signals, the Questyle QP1R’s output was down by 0.2dB at 20kHz. Beyond that, the output for 192kHz PCM (white line, top graph) rolled off fairly gently to be down by 3dB at 45,000Hz and 6dB at just under 60kHz. DSD rolled off a little earlier, as is its wont. There was not much difference between DSD64 (green line) and DSD128 (blue), with both down by 3dB at around 42kHz and 6dB at around 48kHz.

The noise performance at the line output was better than -109dBA with both 24 bit and DSD signals.
 
With 44.1kHz content (bottom graph) there’s no mucking about with gentle filters: the output is down by less than 0.05dB at 20,500Hz and is chopped abruptly above that point. 
We confirmed that the internal impedance of the headphone amplifier was extremely low. Putting 32-ohm loads on the output made absolutely no difference to the output voltage compared to an open circuit, measured to three significant figures. The unit proved perfectly capable of delivering any desirable (and even inadvisable) volume levels into any reasonable headphone.

For 16-ohm loads it managed better than 37mW into my 15.9-ohm load. The -0dBFS sine wave output levels were limited by clipping, not by gain. At 32 ohms the output was better than 42mW, comfortably over Questyle’s specification. In either case, we’re talking about an output of the 1mW sensitivity figure of your headphones, plus 16 decibels. Yes, it will go loud.

For my 295-ohm test load, I measured the output at spot on the 12mW specification, which gives you 11 decibels above the sensitivity rating of your high impedance headphones. Again it was clipping limited, so there’s plenty of gain for tracks recorded at a low level. 
 
Conclusion
The Questyle QP1R is beautifully styled, offers great performance and an enormous capacity. Just make sure all your plugs are small enough to fit.
 
Questyle QP1R

Questyle QP1R portable music player            
Price: $1599

+ Superb sound
+ Massive capacity when microSD slots populated 
+ Build and styling

- Connection cut-outs could be a little larger

Tested with firmware version: 1.0.4
Display: 60mm colour screen, 400 x 360 pixels
Storage: 32GB internal, 2 x microSD slot (up to 128GB each)
Outputs: 1 x 3.5mm line/optical digital audio, 1 x 3.5mm headphone
Other: 1 x USB micro-B
Dimensions (whd): 65.2 x 134 x 14.5mm
Weight: 217 grams
Warranty: One year