Does your dongle dangle daily?
I've been a Digital Audio Player user all the way back to the iPod days, but last year started using dongles with my Macbook & even conducted a
dongle shootout recently.
So when Penon offered to send their new
OS133 dongle in exchange for a review I agreed, and was surprised upon glancing the price - just $34.90.
The OS133 isn't the least inexpensive dongle but can't be far off, sitting at the opposite end of the spectrum from most sources I review. Its' shape is also a bit different, closer to a cable adapter than the usual rectangular dongle.
It'll be interesting to see how much bang-for-buck Penon crammed into this tiny gadget.. now let's get the show underway!
Tech Specs & Ergonomics
Penon's USD $34.90
OS133 USB-C DAC uses a Conexant CX31993 DAC chip with an Analog Devices MAX97220 amplifier to deliver PCM playback up to 32bit/384KHz - amazing for such a tiny device.
The USB-C connector and your choice of 4.4 or 3.5mm jack are linked with black nylon sheathed silver-plated OFC wire Penon use for their
OS133 cable, with 133 cores per wire.
The OS133 is heavier than you'd expect thanks to its solid connectors, weighing similarly to fully-fledged dongles at 27 grams. What differentiates the OS133 is its' form factor - which feels like a heavy cable adapter, rather than a metal rectangle that dangles awkwardly from your phone.
That's one reason I've stuck with DAPs instead of dongles over the years: I don't like how they hang from my phone, always concerned they'll bump into it and scratch the glass. Whereas the OS133 feels more like a natural extension of the IEM cable.
Sound Impressions
Sonically the OS133 is quite v-shaped with an excited tuning that’s going to suit modern music. It isn't dramatically powerful so I wouldn't recommend it for headphones, but delivers ample volume with IEMs. Background noise levels are on the higher side by dongle standards, but not so loud as to be distracting during quiet passages of music.
The OS133 is quite bassy with sub bass in particular being satisfyingly elevated. Bass texture isn’t the most impressive I’ve heard but the extra quantity helps make up for it to generate a fun, bouncy sound that’ll suit modern Pop & EDM nicely.
Being a Penon product the midrange is fairly forward as you’d expect and decently engaging, definitely not recessed which is always a dealbreaker for me, though vocals can be a little dry at times.
Treble's quite elevated, but could use more refinement. I don’t find it distracting but treble notes are a bit one-note & lacking the smoothness you get from expensive DAPs, but this is a $34 dongle after all.
Technical Performance
I find OS133 technical performance respectable for its' extremely modest price & form factor, just don't expect to be blown away here.
The soundstage is decently wide by dongle stands but doesn't have much depth. Resolution's better than expected from something so tiny, but lags well behind more expensive dongles & budget DAPs. It's not so fuzzy that it becomes distracting though, and everything vital for musical enjoyment comes through.
There's a bit of congestion particularly during busy passages when instruments can struggle to remain separated, you won't get much reverb & decay on individual notes nor are they rendered with the delicacy of a decent DAP, but that's no surprise either.
Dynamics are average which creates a smoother sound (which the v-shaped tuning helps 'wake up') and imaging is not the sharpest. Given the form factor I'm not sure how reasonable it'd be to expect more.
Dongle Comparisons
Using my M3 Macbook Air I compared the OS133 with other dongles to get a feel for how it stacks up.
Penon Tail (USD $74.90)
The Tail is vastly more powerful and even comes with a hi-gain switch, making it the better option if you use headphones. Even with IEMs the Tail delivers a far more dynamic, powerful sound.
Tail bass goes deeper and it feels more bass-driven, its' midrange is more forward with greater engagement, and its' stronger amplifier controls & separates instruments better during busy passages.
The Tail's soundstage is deeper and its' resolution especially through the midrange is higher, delivering performance closer to that of a full-fledged DAP. I recommend spending the extra on the Tail if you prioritise performance, but the OS133's form factor is still unbeatable in daily use.
Cayin RU7 (USD $289)
Sonically the RU7's superior refinement is reflected in its' vastly higher price.
The great strength of the RU7's 1bit DAC great is its' remarkably organic, vividly textured midrange which makes the OS133 sound quite digital. The OS133 is bassier in quantity but the RU7 has better bass texture, and is more musically engaging whereas the OS133 can feel flat & uninvolving by comparison.
The RU7 also features lower background noise, better dynamics and a blacker background, greater control during busy passages and a slightly wider stage, along with higher resolution delivered with greater nuance & delicacy.
Conclusion
For $34.90 the
OS133 dongle sounds way better than listening straight out of a phone or laptop.
What really surprised me is the build quality - both wire & connectors wouldn't feel out of place on a cable worth a few hundred dollars. I have no idea how Penon can make them for this price.
Sonically the OS133 is probably good enough for a noisy train ride, and more convenient than a conventional dongle which will bang up against your phone. Using the OS133 feels like plugging IEMs directly into your phone through an adapter, ergonomically it's tough to beat and when price is taken into account is very easy to recommend.
I'd love to see Penon offer a few different wire choices as drop-down menu options, perhaps allowing a downgrade to cheaper wire or upgrading to pure silver for a different flavour.
The OS133 is perfect for max portability without the hassle of carrying & charging a separate device.