JDS Labs O2 – OL-DAC

Before starting this review, I would like to share the technical aspects and package details.

Also, I am so thankful to Jude from JDS Labs for giving me this opportunity.


 Objective 2

Frequency Response +/-0.1 dB (20Hz-20kHz)
THD 1 Khz 150 Ohms 0.0016%
IMD CCIF 15 Ohms 0.001%
IMD SMPTE 0.002%
Noise (ref 400 mV) -105 dB
Max Output (33 Ohms) 613 mW
Max Output (150 Ohms) 355 mW
Max Output (600 Ohms) 88 mW
Output Impedance 0.54 ohms
Crosstalk (15 ohms) -65 dB
Channel Balance (50% volume) 0.6 dB
Battery Run Time 6-8 Hours


Package Contents
Objective2 Headphone Amplifier

15VAC Power Adapter

2x Tenergy 9V NiMH, Low-Self-Discharge Batteries

Rubber Feet



Frequency Response 10Hz-20kHz+/- 0.15dB
THD+N 20Hz-20kHz< 0.001%
IMD CCIF 19/20 kHz -6.03 dBFS0.00033%
IMD SMPTE -6.03 dBFS0.00031%
Noise (A-Weighted)-109 dBu
Dynamic Range (A-Weighted)114 dB
Linearity Error -90 dBFS+/-0.01 dB
Crosstalk -10 dBFS 100K RCA-108 dB
USB Jitter Components 11025Hz-116 dB
PCB Stackup4 Layers
Maximum DAC Line-Output, 100K2.00 VRMS


Package Contents

OL DAC v1.10

15VAC Power Adapter

3ft USB Type-A Cable



Surprisingly, JDS Labs devices are designing and producing in USA. I think that JDS Labs can request higher prices easily with regard to audiophile product prices in the market recently.

Objective O2 and OL DAC is quite portable for desktop usage in terms of its size. O2’s capable of being used on-the-go but not as good as like Hugo or Mojo. Both O2 and OL-DAC are same size. Their height and width measures are small and it only needs a tiny space. Both devices are made of high quality aluminium material, finish points are clean and smooth, material and workmanship quality are extremely successful and durable.

Both devices require A/C adaptor however you can use O2 with battery. Portability is not so necessary even but, in some cases it is quite useful. Battery life is somewhere between 6 hours to over 8 hours but it depending on use. Volume knob is very soft and can be adjusted easily, it does not feel cheap and cheesy; in that kind of amp’s, volume knobs might be unbalanced and slack. You do not hear hiss while adjusting volume knob. Almost all of the functions and outputs are integrated onto to front panel which I found very practical. At the end, I really like O2 and OL-DAC in terms of design, workmanship and material quality in the overall.


Output Power:

O2’s is powerful than I expected. Probably, it is enough to drive almost all the headphones with authority in the market. O2 is very suitable for IEM which I really like its harmony with the IEMs I have. I also would like to indicate that I did not hear any disturbing hiss with low impedance IEMs. Andromeda is very sensitive earphone and I didn’t hear any disturbing background noise. I listened O2 with all IEMs volume knob 4/1 ratio. I also would like to remind that O2 is so powerful for IEMs and it is better to control your previous sound level for your earphones and ear health before listening it with IEMs.


Sound Type:

I absolutely like the sound quality. O2’s sound character is quite transparent and clean, contrary to my expectation. General presentation of O2 is very neutral and it doesn’t bring anything in front. It presents the sound naturally without colorizing and its relatively light and bright tone. Both bass, midrange and treble were exceptionally fast and sharp. Overall instruments tune is neither thick nor thin, it is in between. It is able to stay partly musical without being boring. There is balance from lower to upper frequencies in overall presentation and none of the frequencies are overlapping. High-resolution files sounded very fine with 24-bit, AIFF, WAV and DSD audio.

It is effortless in overall and it is providing a clean, smooth listening. In this price range, many of the earphones feature the warm musicality instead of delivering technical performance due to the high cost and workmanship of detailed technically successful products. However, O2 surprises me by delivering technically good performance because I used to see this performance in a higher price range. I believe that O2’s and OL-DAC’s performance is above it price and I have to admit, it’s pretty impressive at this price range.



I felt the treble to be well tamed with good extension and it also has a very detailed and naturally textured extension. It’s significant in the overall presentation and they are not sharp and It is very well extended without being sharp or unnatural. Upper frequency presentation is extended, effortless and pretty clean. You do not face any aggressiveness while listening to music. I listened to almost all the treble-dominant IEMs but I did not run across to any diffused or uncontrolled trebles. I really liked these controlled trebles that know where to stop.  It is very successful in terms of instruments distinction and positioning. I can easily define the cymbals’ position in Rock based tracks, cymbals are not unnatural generally. It’s also effortless, so It is not tiring the ears while listening and not getting out of the hand while giving the detail.



Mids are neither front nor behind in the overall presentation, same as the other frequencies. Their quantity is almost same as the trebles and their character is not disturbing. There is no sharp or bright presentation, the character of the mods is linear accompanying to the overall presentation. Bass frequencies do not crush the mids and there is no mid hump in low mids. Instruments plays organic and realistic. Mid presentation is spacious and detailed in general. Vocals are enough detailed and impressive for many listeners, they are centrally located in the overall presentation. You can hear the vocals very clear and bouncy. Vocals and instruments have good and natural textures that make the music enjoyable and musical. It is very easy to understand that there is no veil and it is very close to the realistic tones of instruments. Mids are very easy to listen it and it offers a joyous listening for hours without boredom.




Low end is clean and detailed. The quantity of lower frequencies is quite satisfying, it is not too much, it is detailed and controlled. Bass quantity varies from earphone to earphone but its overall bass quantity and tones are slightly more than neutral, so the bass quantity is enough for many users. Sub-bass is there, but it is rolled off and laid back little bit but somehow sub-frequency is fair enough, relatively the presentation is soft and easy. I really like sub frequencies because the quantity is not more than necessary. General presentation is controlled and do not spread. There is no bloat or overhang and It has good timbre and presence. Punch and speed of the bass is fairly enough. Bass does not loose its control and it’s fast in tracks, so it does not tire the ears in this term.



The soundstage is spacious with an excellent layering and precision. Stage is quite wide located however the depth is relatively good. It spreads the instruments into a spacious and wide area, there is enough distinction space for the instruments. The layering is very well done with a lot of air between them and every instrument. Background is quite silent and instrument distinction is successful. There are not any issues like mixing all instruments. I also found the background of device is clean.




The O2 and OL DAC combo is an exact price/performance combo in terms of size, sustaining IEMs and over the headphones and being a good desktop alternative.  They produces a great deal of clean detailed sound and power from a compact size. Also, it feels solid and aesthetically is top notch at this price. Another reason why I like this combination because the presentation is slightly musical and technically good. I think the harmony will be good with most of the headphones and the main reason of it is the balanced sound frequencies. Would I recommend this combo? Absolutely yes! I can easily recommend this combo to every audiophile and I have no doubt this is a fantastic-sounding dac-amp combo compared to other products of the same form factor at this price range.

I look forward to seeing many products in the JDS Labs for years to come.

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