Until recently Shonyun only sold their headphone amplifiers in China but now that has changed. The SH-306 is the higher end model of two portable headphone amplifiers and is available on eBay now for £115.
The SH-306 is based on opamp+buffer structure. using the AD8397ARDZ opamp on both stages. Like it's larger desktop brother it uses KOA resistors and ELAN capacitors. It is powered by five 3.7v Li-Poly batteries that provide 21V when fully charged. The smart charger and protection chip stop the charging when it reaches 21V, which can be done while in use. When the batteries are running down they get cut off when the charge drops below 15V. Typically it takes about 8 hours to deplete from a full charge, if that seems short bear in mind this is a class-A amplifier. Dimensions measure 130x74x28mm. With a full metal chassis and a weight of 260g it's a bit of a tank, but as tanks go I thought it was quite a pretty one and well built too. Without further ado, lets get to the good stuff...
SOUND
The power on tap here is pretty epic and one that would better suit larger, less sensitive headphones. The bass is deep and interestingly textured for a portable unit. It doesn't kick as hard as some but it certainly isn't lacking either. The sonic signature is a little forward in the upper ranges, but otherwise it's a fairly unbiased presentation. The high frequencies sparkle nicely although they can sometimes be a little overzealous. The crispness can sometimes get overwhelming and feel a little muddled but generally produces great detail. The soundstage is very impressive, with admirable depth and spacing.
PORTABLE AMPLIFICATION
Although measuring about the same length as an iPhone 4 and looking pretty great sat on top of the SH-306, the sonic style didn't make a good match. Both the iPhone and Shonyun push the high frequencies a little too much without sufficient control, causing sibilance a bit too easily for my liking. I found a much better pairing connecting the Shonyun with either a Samsung Galaxy S or a Google Nexus 7, neither of which had a line-out capability but despite the dual amplification the sound was a nicer one.
DAC AMPLIFICATION
Connecting the the SH-306 to a proper DAC was a much more interesting experience. I connected the SH-306 to: The Epiphany Acoustics EHP-O2D, iBasso D7 and Yulong D100 mkII. This produced better results than connecting it to a portable media player but apart from the iBasso the Shonyun was bettered by these DAC's internal headphone amplifiers. This isn't quite fair given their higher price tags but I couldn't help be a little disappointed that a dedicated amplifier couldn't be more impressive.
COMPARISONS
The Fiio E17 is primarily a DAC, but it can also be used as a battery powered amplifier like the SH-301. These two amplifiers also share a similar price tag and both black metal boxes are designed and built in China. The Shonyun largely excelled here with a more three dimensional soundstage. The Fiio sound is cleaner and more open but it also had a tendency to be more harsh / less smooth. The slightly more textured bass presentation and better rendered detail rendition the Shonyun made it a winner for me.
The Epiphany Acoustics EHP-02 is a similarly priced and specified machine, also having internal rechargeable batteries. It's amplifier isn't class-A and although it has gain control it did display some distortion. The volume dial feels more delicate on the Epiphany but it turns more smoothly, is easier to grip and doesn't turn the unit on (all big pluses to me). Build quality wise the Shonyun wins hands down, but sound wise it's not quite so promising. Unfortunately for Shonyun the Epiphany had a more enjoyable presentation for me, being warmer and more smooth, with a more laid back treble and airy feel that solidify it as my choice at this price.
BUILD
The construction of the SH-306 is really very nice. Almost every part of this unit is heavy metal, all beautifully crafted, well put together and seems like it could survive a knock or two. Even the volume control feels on the tough side and although I like the look of the smooth surface here, while using it I would prefer it had more grip. At 260g it's perhaps a bit too heavy for some. At more than double the weight and size of the Fiio E17 it's quite a substantial device but it's not enough to put me off.
I was considerably more impressed by the build quality here than with Shonyun's more expensive desktop amplifier (SH-301 pro). The balance of features and audio quality is totally different between these two models, it's like they were designed with entirely different idea in mind.
The plastic around the volume dial glows red when charging or blue when on. This is a nice touch so you don't forget about it in either case. It also feels like it would even act as a bit of a shock absorber if anything was to knock the dial too. This is a much nicer implementation of coloured lights than with the SH-301 (desktop amp), but the fact that the SH-306 is cheaper helps here too.
The input and output connectors and are recessed into the heavy duty metal front panel. They are both 3.5mm (1/8") which is probably fine for most people, but I would have liked to have seen a larger 6.35mm headphone connection here. Rather frustratingly the recessed connections make it difficult to fit the adaptor for a larger headphone plug too. The straight adaptors just wont fit so I bought a cable adaptor, but this too would not fit. I eventually found an 'L' shaped adaptor with a slightly smaller footprint which did fit - just, but be warned - this amplifier is not friendly to the larger headphone connections.
The Shonyun SH-306 is a capable performer and a device that you can be proud of. Both size and weight are a bit excessive, the battery life is not great and if you have headphones with a larger (6.35mm) connector the design of the front panel could grate your nerves, but... If that doesn't put you off and you're looking to drive some demanding headphones, in a pretty black metal box, with a sound signature on the brighter side then this could well be the amp you're looking for.
