Stoner Acoustics UD130 amp/DAC – on a sonic roll

STONER ACOUSTICS UD130 amp/DAC

+ Precise imaging; ease of use, portable; that sweet, sweet midrange; neutral presentation; very clean headphone output.
– Not the most beautiful amp out there; none at this price.
Sound: 8/10
Value: 9/10

The UD130 is a new portable DAC/amp from Stoner Acoustics, just released as a replacement for the UD125, which was already very competent. Perhaps what sets the UD130 and its predecessors apart is the absence of a battery. The unit draws power from the equipment upstream. This might sound a little intimidating at first, but throughout the review period, the UD130 ran fine, even if it did reduce the phone battery’s life noticeably.

The UD130 is very small, measuring roughly 85 x 58 x 18mm. There’s nothing much going on with the unit, with only one micro USB input at the back and a USB Audio class 1/2 toggle switch. In front, there’s a mini-jack for your earphones, an LED indicator, a pushbutton switch to select the gain, and a volume control – which we will get to in a minute.

Overall the unit is very light and box-like. It won’t win any beauty pageants, but by keeping the looks of the unit simple, Stoner Acoustics has managed to produce it at a price that’s even lower than the UD125.

“Most of the architecture blocks were lifted from the UD125, with inspiration from the UDX. We would even go as far to say that the UD130 is quite the mini-UDXA,” says Stoner Acoustics designer and founder Ooi Tze Yang.

“In terms of sound quality, we have a few architecture blocks that worked very well with our customers. Many were particularly happy with the UD125’s output stage arrangement. You could say that for the UD130, we chose all the best things our customers liked and put them in a very effective arrangement,” he adds.

Inside, the UD130 sports the flagship newly-released AKM AK4493 DAC chipset which replaces the previous generation AK4490 chip. Not only boasting the top of the line DAC chip, the UD130 also runs on a 255-step digital volume control with 0.5dB adjustments, allowing you to use even the most sensitive in-ear monitors.

Although the Pico Slim inspired volume curve took a while for me to get used to, it proved to be an amazing ally that accommodated my sensitive JVC HA-S500 and the harder-to-drive Sennheiser HD525 and Hifiman Sundara. The gain switch also allows you to bump up the gain, which helped the Sundara sing.

The headphone section uses a Texas Instruments TPA6120, an impressive headphone amplifier chip giving the unit a THD of <0.001% at 20Hz-20KHz and a dynamic range of 128dB. With the exception of very hard-to-drive headphones, the UD130 will be adequate for virtually any of your cans.

LISTENING
I spent a lot of time with the unit, probably too long, I might add. Because of the diminutive size, it followed me everywhere – from home to coffee shops to the office. While most of my listening was done at the office, the UD130 was also my bedside rig.

With USB audio class 1, the unit plugs and plays without any drivers. The driver for it can be downloaded from the product page and with USB audio class 2, it will support up to DSD 256 and DoP 128. Aside from that, the unit supports USB OTG so it paired well with my phone. I can’t express how delighted I was at the support for even Tidal’s MQA files.

The headphone out is very clean and quiet. With sensitive cans, there’s no hiss at all, and there was a proper black background. I also spent some time listening to it at low levels, where the UD130 retrieved detail well, although some busy songs like Guilty All The Same by Linkin Park and Hail to The King by Avenged Sevenfold still needed the extra volume to shine.

Diana Krall’s Live in Paris is always a welcome album for me to test equipment with. The UD130 reminded me of the imaging shared by its predecessors – focused and sharp, a definite step up from the headphone out from most phones. It’s easy to realise the value of an external DAC and amp when you compare them side by side.

Moving onto something more modern with a retro-futuristic twist, Muse’s Simulation Theory sounded perfect on the UD130. The treble energy was never overbearing with the right amount of extension, and the transition between lower treble and upper mids was smooth, lending a lot of enjoyment to track number six – Something Human.

I think the sound impression wouldn’t be complete without some pop music because, let’s face it, pop music nowadays is getting better and I am not ashamed to say I listen to a lot of Billie Eilish, Joji, Cuco, Ariana Grande, and more with the UD130.

Idontwannabeyouanymore [sic] by Eilish sounded ethereal with genuine emotion. Her prominent voice revealed the quality of mids from the unit. The UD130 has a neutral presentation with a slight tendency to be warm. Slow Dancing in The Dark by Joji has some very low notes but these were easily reproduced by the unit. Suffice to say, when it comes to pop music, nothing really fazes the UD130. Presentation was always clear and effortless.

THE LAST WORD
Perhaps what’s most important for me from a portable device like this is the cleanliness of the output and the ease of use. With that regard, the UD130 checked all the boxes. I was wowed by the clean power delivery it could provide to both my sensitive and harder-to-drive cans. All this from a unit that has no battery, requiring only one cable, making it my favourite companion when I’m out and about.

Stoner Acoustics seems to be on a roll, churning out one good product after another using premium components in the signal path. The UD130 continues providing good sound for very little money but since this was designed as a portable component in mind, you might want to look elsewhere for a desktop set-up.

Gear
Sources: Acer Aspire V5 573PG, Tidal Master, Spotify Premium / DACs: Matrix Mini-i, Chord Hugo v1 / Amp: Lovely Cube Premium / Headphones: Sennheiser HD525, Final Audio Pandora Hope VI, JVC HA-S500, Hifiman Sundara

Price: US$80
Malaysian price: RM300
Review sample courtesy of Stoner Acoustics.