This is a review and detailed measurements of the Cowon Plenue 2 portable Digital Audio Player (DAP). It is on kind loan from a member. The Plenue 2 costs US $599 with Prime shipping. The owner took advantage of a 20% sale so price may be lower.
EDIT: List price seems to be US $1599.
The Plenue 2 feels quite chunky and heavy and is in typical style of other DAPs:
The exception is two rotary controls. The top one is dedicated to volume control. The other is a multi-function one that can be assigned to different purposes.
I am not a fan of either control. The knobs are too small to rotate even though I have rather narrow fingers. Worse yet, there is no acceleration in volume control. By default it sets the level to mid-point and you have to crank it forever to get up to max value of 140.
Cowon does not list this player in their support page so I could not get a manual for it there. I found it elsewhere but formatting was poor, often overlaying chinese characters on top of text. There is not much that is intuitive in the interface.
For testing, I connected the unit over USB to my Windows 10 system. It prompt me the option of acting like a DAC or "MSC." I happen to know that MSC stands for Mass Storage Class driver but I suspect most people don't. Why not say "file storage" or some such thing that makes sense to people? There is plenty of space on the unit.
Going into settings menus, I was greeted with a bunch of Chinese characters. I am not sure if there is a language selector or not. If you look above, my sample audio signal also has some chinese characters below it. Why?
Anyway, let's get into testing.
DAC Audio Measurements
As noted above, I started my testing the unit while connected to Windows 10 PC using USB cable. I put the unit in DAC mode and started my dashboard measurement:
View attachment 32122
This is actually pretty reasonable output with 2 volt RMS and pretty low level of distortion and noise in a portable package. SINAD of 105 dB is decent. However, when I started the test, the SINAD was jumping between 98 (or was it 92?) and 102. Distortion products were not changing but the noise level would constantly jump and down. Strangely that started to settle down after a few minutes. My guess is that when it first "boots" there are background processes that are causing CPU activity that is bleeding into the DAC.
Using the "warmed up SINAD" we are securely in second quarter of all DACs tested which is good:
View attachment 32123
Dynamic range at full volume is good but drops a fair bit when measured at just 50 millivolts for sensitive IEMs:
View attachment 32124
View attachment 32125
Intermodulation distortion versus level was excellent:
View attachment 32126
There are some variations though and that was what I was seeing in a more magnified way when the unit had just booted.
Low level of distortion contributes to low intermodulation distortion with 32 tones:
View attachment 32127
That is 120 dB or 20 bits of distortion-free dynamic range which is very nice.
Jitter test shows some interference in the output of the DAC but is not of any audible concern:
View attachment 32128
Filter response is "slow" as is fashionable (but incorrect) these days:
View attachment 32129
There are different filter settings though and if I could manage to navigate the unit, I could have changed it.
THD+N versus frequency shows high level of noise and distortion due to wide bandwidth of this test, extending to 90 kHz:
View attachment 32130
We can dig into the cause by looking at the 90 kHz bandwidth of a 1 kHz tone:
View attachment 32131
Our 1 kHz tone is hugging the left side of the x axis. We see the distortion products which are all less than 110 dB which is good. But then we see a pair of tones around our sampling rate of 44.1 kHz, indicating aliasing products due to slow filter. Translating in English, the actual distortion products are very low as our SINAD indicates. What pushes the above graph high is ultrasonic products which should be benign at those levels. A sharper filter setting would eliminate most of it.
DAP Mode Audio Measurement
To make sure performance was the same in DAP mode versus PC connected, I ran the dashboard without USB connection and local playback from internal memory:
View attachment 32132
Distortion products are the same. Noise level improves without connection to the PC (bottom of the distortion spikes) but is of no audible consequence.
So you can trust the rest of the measurements to be representative of local playback.
Headphone Amplifier Measurements
Let's measure power versus noise and distortion into a 300 ohm load:
View attachment 32133
Wow, that is very low level of noise and distortion, essentially matching the excellent Topping DX3 Pro in low gain. At peak power distortion is down 106 db which is very nice. Won't get super loud though at just 11 milliwatts.
Switching 33 ohm load to emphasize current delivery, makes the unit sweat a lot more:
View attachment 32134
The Plenue 2 has balanced output using 2.5 mm jack so let's compare that and the 3.5 mm jack using 50 ohm load:
View attachment 32135
The balanced mode provides not only more power but also a lot less noise and distortion. So it seems the process of conversion to unbalanced is adding good bit of distortion and noise.
Output impedance is a very good 2 ohm:
Note: the original review had this wrong at 16 ohm. Corrected above.
Headphone Listening Tests
There was sufficient power and good fidelity to drive the Sennheiser HD-650. With recordings at lower level than 0 dB, I had to ride the volume control to max but that was good enough.
Switching to Hifiman HE-400i, I had even more volume and a very nice experience.
Overally, there was not much to fault the subjective performance of Cowon Plenue 2.
Conclusions
You probably don't want to listen to me ranting about the lack of usability testing on these devices. They could use some serious testing and refinements of the control. I suspect though once you get used to them, you can figure out your way around.
From performance point of view, the Plenue 2 delivers. It acts as a desktop class DAC when connected to the PC, with little to fault it. It generates the same performance when playing locally which is excellent. Power level in unbalanced mode is just enough with every low distortion figures for 300 Ohm load. For lower impedance headphone, better use the balanced connection for most power and least distortion and noise.
Subjective performance was positive as well as measurements would predict. It just won't blow your head off as some battery operated portable DACs can do.
Overall,
based on measurements and listening test performance, I am happy to recommend the Cowon Plenue 2 DAP.
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As always, questions, comments, recommendations, etc. are welcome.
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