Questyle

M15 Portable Headphone DAC / Amplifier

£222.73 direct from Questyle

Dongles. What a reality we live in! Apple delivered the one-two punch here. First, the iPhone was the trailblazer when it came to dropping the headphone jack, which is now the norm on smartphones. Then, Apple launched its headphone dongle – a dangerously under-priced, over-performing show-stopper of a headphone amplifier that disrupted an emerging market for portable USB DAC/amp combination products. But these days, people are starting to expect more from their portable devices, especially the audiophiles among us who are looking for something a little more feature-rich than just an adapter.

Price-wise, the new Questyle M15 mobile DAC sits smack-bang in-between Dragonfly's incumbent Red and Cobalt offerings and is packed full of proprietary Questyle gizmos and gadgets. So, is it worth considering for the discerning, dedicated portable headphone user?

UP CLOSE

The M15 is a clear winner for the nicest-looking mobile DAC I've laid eyes upon. Instead of cheap plastics or rubber, Questyle has opted for an all-metal design, with a window that allows you to peep into the internals. These look lovely – it's all solid-state, so no glowing valves or anything like that, but there are two glowing LEDs that indicate things like power and connection status and bitrate and sample rate.

The chips inside don't just look fancy, as they include the flagship ESS ES9281AC DAC, which feeds into two amplification modules, both of which have dual amplifier engines. So really, it's a classic Questyle overkill moment, using four amplifiers for a product that can easily fit inside the small coin pocket that most jeans have.

This allows for playback of anything up to DSD256, and even MQA unfolding if you're into that sort of thing. The LED lights inside cheerfully remind you of the sample rate you're listening to. Unfortunately, there's no way of turning these off, so I had to try to conceal my M15 when listening in the cabin of a full red-eye flight.

There's no volume knob either; it's all driven internally via the source device. Gain is manually switched, instead of the automatic switching module found on the younger, cheaper, Questyle M12 unit. You can use a standard 3.5mm plug, or 4.4mm TRSS balanced output if you're planning to go crazy on the train.

THE LISTENING

Consistency is crucial for a portable DAC, and the M15 doesn't disappoint. I appreciated its consistent nature when swapping between sources. The interface would change when I plugged it into a phone, tablet or computer, but the listening experience didn't…

Using my trusty Sennheiser IE600s, via a balanced 4.4mm TRRS connector, I fired up the subtle stylings of Quiet City by Alison Balsom. Even with the low gain setting, there was enough headroom to build a house. This didn't deter the excellent dynamic range and razor-flat, neutral response that the M15 produces. This had me thinking; surely this can't drive big, thirsty planar magnetics? I was wrong. The Audeze LCD2 sings comfortably, regardless of music genre. I can only imagine what this would be doing to the battery life of my source device. Still, Questyle says that the dual CMA amplification systems inside the device mean that power consumption is minimal.

During IEM and large planar magnetic headphone testing, the unit never once became hot and didn't have any glitches, stuttering or technical issues. It was just music, as expected, from start to finish. Almost as if I didn't use a dongle at all! And it was great to see that even with all of the technology packed into this unit, there was no explicit colouration of the frequency balance or noticeable distortion. It also seems to have a low enough output impedance not to cause any wonky issues with sensitive IEMs, but I'd recommend using these through the 3.5mm output to be safe.

THE VERDICT

It's a real shame that the headphone jacks are rapidly disappearing from our smart devices, but it's good to see that there are still output options for those of us who refuse to accept Bluetooth headphones. If you need audio output, you can always go for the cheap and cheerful options on the market. But this unit is most worthy of your consideration for the discerning, dedicated portable headphone user who needs their portable DAC to pack a punch.

For more information visit Questyle