Preamble:
Before I start with my review, I’d like to thank Yulong Audio for providing me with a sample of their U200 in exchange for my honest opinion. Please note that I’m not affiliated with Yulong Audio in any way.
The U200 is the U100’s (which I used to own some years ago, and it could satisfy me with every headphone I used, so I’ll include some comparisons in my review) successor that was improved in many ways, not to say all.
Technical Specifications:
USB input supports PCM 16-32 Bit, 44.1KHz, 48KHz, 88.2KHz, 96KHz, 176.4KHz, 192KHz, 352.8KHz, 384KHz, and DSD64 and DSD128.
USB supports Mac OSX, Linux, and Windows XP to Windows 8, 32 bit or 64 bit system (driver required).
Signal to Noise Ratio: 120dB
Dynamic range: >115dB
Distortion: 0.0016%
Frequency response: -0.2dB @ 20Hz and 20KHz
Crosstalk: -110dB
Maximum line output: 2V RMS
Headphone output power: 60mW @ 600Ω, 150mW @ 300Ω，280mW @ 250Ω, 500mW @ 32Ω
Power consumption: <15W
DAC: AKM4495
Amp: Class A
USB controller: Saviaudio SA9227
Delivery Content:
In contrast to its predecessor, the U200 comes with partly slightly less accessories and lacks of a traveling pouch, a 6.35 to 3.5 mm adapter and 3.5 mm to RCA adapter, although the latter is not necessary due to the analogue RCA inputs.
The cardboard box the amp arrives in is very sturdy and well bolstered and shows a blue-coloured audio measurement graph on its outside.
Next to the amp itself, it contains the WiFi module, the fitting antenna, a USB cable (that is usable with the WiFi module and a PC), a power cord for connecting the U200 to the WiFi module, self-adhesive foam feet for the WiFi module and last but not least a grounded IEC cable with Chinese pin-layout.
As the U200’s (which is by the way longer than its predecessor) power supply is now integrated to the case, one doesn’t have to buy a separate power supply that fits into German/European wall sockets, but can use any grounded IEC cable.
Looks, Feels, Build Quality:
The black brushed metal housing looks timeless, feels very well and is comparatively heavy in weight and very well built. The hexagon socket screws are flush bordered into the front, just as the Yulong emblem.
On the far left is the analogue power switch (that doesn’t have a power-up delay, just like the U100), next to three orange LEDs that indicate power, playback in USB and WiFi DAC mode and DSD playback. The recessed 6.35 mm headphone jack is located on the right half of the centre, next to the volume potentiometer that is on the right, which is not stepped like the U100’s, but free-running and has got a good resistance that doesn’t feel too loose.
One will notice several changes on the U200’s back. Next to the RCA DAC Line Out is now a pair of analogue RCA Line In sockets, as well as a source selector switch (that I’d rather liked to see on the front or alternatively two source indicator LEDs) next to the USB input that can either be used to connecting a PC or the WiFi module. Right to the USB output is a 5 V DC output for powering the WiFi module.
A useful improvement was to move the power supply into the U200’s housing, wherefore just an IEC cable with country-specific pin layout is required for powering the amplifier. Underneath the IEC socket is an easy accessible port for the fuse with a spare one next to it.
The small WiFi module has got a connector for the antenna, a 5 V DC input for using the U200’s 5 V DC output, a USB input (wherefore no special cable is required for the connection), a reset button and three orange LEDs that indicate power, operational readiness and possible fails.
Features:
General:
In general, the U200 has got a whole range of additional features and improvements compared to its predecessor, the U100.
Besides the improved ingredients (the power supply has moved into the enclosure, the Saviaudio SA9227 chip is used as audio interface, a renewed customized ultra-low phase noise clock is used to reduce jitter and noise from the audio signal, and the great AKM4495 DAC chip is used for the USB decoder), the front features additional LED indicators and the rear has got a dedicated pair of analogue RCA inputs along with a source selector switch and a digital USB input that can also be used for connecting the WiFi module with its antenna and power supply, which allows wireless streaming from Android and iOS devices and can also be used for accessing media servers together with the Yulong app for Android and iOS.
The U200 is able to decode PCM files with a bit rate of up to 32 bit and a resolution of up to 384 kHz and DSD files both in USB and wireless mode.
Headphone Amplifier:
The U200 can also be used as pure headphone amplifier only, wherefore it has got, unlike its predecessor that featured just a 3.5 mm analogue input, a pair of dedicated analogue RCA inputs on its back.
USB-DAC:
For using the U200 as USB DAC with a Windows computer, one firstly has to download and install the required audio drivers from the Yulong website. It’s not plug and play, but it is so easy that chances to fail are minor and the installation process is fairly easy and fast.
After a system reboot, the U200 can be selected in the Microsoft control panel’s audio settings.
I used the U200 with Foobar 2000 as playback software with additionally installed ASIO, DSD and SACD drivers.
WiFi-DAC:
After just a few seconds of initialising after powering on, the WiFi module is ready to use, which can be seen by the orange “Fail” LED disappearing.
With iOS devices, one has to select “YULONG Audio” in the wireless network settings, and then the iDevice connects to the U200. In the quick settings (that can be accessed by sliding from the bottom of the screen to about its centre), one then has to select the U200 as Airplay device, then music is played through the Yulong U200, which then also shows an orange shining “Play” LED on its front.
A convenient thing is that the Volume can be lowered in the iDevice’s playback software (just as when it is used as USB DAC with a Windows PC) to gain a better adjustment range with sensitive headphones and In-Ears.
With the iOS app (there’s also an Android app), the U200’s wireless display name can be changed, and, as it seems, the DAC can be used to access a NAS server.
I didn’t further test with Android devices, integrated networks and NAS, as I lack of experience in this field of application and failed getting it working, but DSD and 32 bit PCM playback are also possible with them.
Airplay with iDevices however worked great and easily with easy setup.
Sound:
I evaluated U200’s sound, for its class A amplifier Yulong suggests a warm-up time of at least 15 minutes, with full-sized headphones (Superlux HD681, Beyerdynamic DT880 600 Ohm, Sennheiser HD 800, Audeze LCD-X) and In-Ear monitors (Etymotic ER-4S, Ultimate Ears Triple.Fi 10, Shure SE846, UERM).
Source devices that were connected analogue (a) and digitally (d) were my iPhone 4 (d), my Windows 7 Laptop (d), my iBasso DX90 (a) and Pioneer PD-S 701 (a); music files were stored as MP3s (320 kBps cbr), AACs, CDs, FLACs, Hi-Res and DSD files.
Output Impedance, Frequency Response:
Although the potentiometer has got a good channel matching right from the start, it shows some minor imperfection with the U200 I received. Almost over the whole adjustment range, it shows some slight imbalance of (depending on its position) 1 to 0.5 dB – the U100 I used to own behaved better as it had perfect channel matching after just four steps, but I know at least one owner that had a U100 which showed slight channel imbalance, just as my U200 now does. I guess it is due to minor production tolerance of the potentiometers.
Imbalance is moderately audible with sinus and pink noise signals, but only very slightly audible with music and only with very hard concentration, and it can be corrected in the Windows sound settings when used as USB DAC.
Except for the minor channel imbalance, frequency response is commendably flat, just as it should be and my (unloaded) measurements below prove:
Analogue Input:
USB-DAC:
WiFi DAC:
Frequency response also remains commendably flat with critical In-Ear monitors that have a varying impedance response, such as the Ultimate Ears Triple.Fi 10 that will get a highly altered frequency response when connected to high-impedance sources, which the U200 isn’t:
The deviation of just less than 1.5 dB shows that the U200’s output impedance is less than 2 Ohms (and therefore iPhone 4S-level, a device that has shown to be one of the best smartphones for critical In-Ears due to its quite low output impedance), which also makes the amplifier suitable for critical In-Ears with multiple Balanced Armature transducers, although it is better suited for full-sized headphones due to the lack of a gain switch and the high output power, but it is good to know that the Yulong engineers developed the U200’s circuit so well that it even performs extremely well with critical In-Ear monitors with varying impedance response which is due to their crossovers and multiple Balanced Armature transducers. With dynamic In-Ears and full-sized headphones, frequency response is just as perfectly flat as without any load at all.
Just as its predecessor, the U200’s output impedance is very low with less than two Ohms.
Hissing:
With all of my tested full-sized headphones and the ER-4S, I couldn’t detect any hiss or ground noise, just as I expected from a well-designed amplifier circuit, and even with my sensitive UERM and Triple.Fi 10, hiss was extremely low and close to being inaudible. With one of my most hiss-revealing IEMs, the Shure SE846, I could hear some ground noise, but it was covered by the music, even in rather quiet passages, once I started playback.
That there is only little hiss even with very sensitive multi-Balanced Armature In-Ear monitors shows that Yulong’s engineers did a great job in terms of clean implementation – neat!
Resolution, Precision, Soundstage:
If I had to subjectively describe the U200’s sound, I’d say its signature is very clean, rather on the analogue-smooth side than analytical, but with detailed highs and an overall high resolution.
Lows are precise, though rather on the musical side, but without sounding undefined or imprecise or even slow, and have got a good amount of details and impact.
Mids are detailed and lush; voices are reproduced very well and detailed.
Highs are rather on the analogue side too, but are high resolving, but with a slightly forgiving character and zero listening fatigue.
The DAC’s and amplifier’s resolution are on a high level and the U200 doesn’t have any problems driving high impedance cans or critical In-Ears with varying impedance response.
Soundstage is of a good shape and balanced in terms of width and depth and with good imaging and spatial presentation and three-dimensional.
Differences between the Inputs:
Analogue Input:
With the WiFi module being connected, there is some minor noise (that disappears when it’s disconnected), but only with sensitive IEMs. I can’t say whether it occurs because of EMP interferences from my WiFi router and other radiation or comes from the WiFi module itself, but it is so small and only audible with the Shure SE846 (and inaudible with the ER-4S and my full-sized headphones) wherefore it is irrelevant, as the U200 was mainly developed for full-sized headphones, although it performs extremely well with In-Ears, too.
USB-DAC:
Sound in USB DAC mode is highly transparent and detailed and lacks any interruptions or other interference.
WiFi-DAC:
To my surprise, sound remains transparent when using the WiFi module and is on the same level of resolution and precision as with the USB DAC or analogue input, but shows some interference noise in rather quiet passages of the music, even with full-sized headphones. If it occurs due to EMP interference of my WiFi router and other devices or is generated by the module itself isn’t fully replicable. As it only occurs in rather quiet passages, it may only be bothering with music that has got a high dynamic range with suddenly changing volume and very quiet passages and low listening levels.
Conclusion:
The successor of the already excellent U100 features fundamental improvements with today’s decoding electronics and a subjectively and metrologically excellent sound and premium and solid build quality. Ground noise is extremely low and far from being audible with full-sized headphones and even very low with highly sensitive In-Ear monitors.
Sound is transparent, smooth and very detailed, and the amplifier doesn’t have any problems driving high impedance and low sensitivity headphones with its powerful 2 V class A section. Sound remains transparent and doesn’t lack behind wired inputs (except for some minor noise) when the WiFi module is being used.
The only small criticism I have is the (with my sample) small potentiometer imbalance of between 1 and 0.5 dB, although there is quite a good balance right from the start and this slight imbalance can only be heard with mono recordings or very hard concentration. Two other things that I found somewhat unhandy are that the source selector switch is located on the back (I’d prefer it on the front or source indicator LEDs on the front instead if the switch remains on the back) and that the amplifier lacks a power-up delay, but those are just very minor flaws in my opinion and are up to one’s personal preferences.
All in all, I can definitely recommend the superb U200 that is well made and has a subjectively and metrologically great sound.
