A High Performer for a Low Cost, but Don't Mind the Front-Panel!

A Review On: JDS Labs Assembled Objective2 Headphone Amplifier

JDS Labs Assembled Objective2 Headphone Amplifier

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Price paid: $156.00
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Pros: Excellent sound quality, great price/performance ratio, battery and/or AC powered, adjustable gain options, no background hiss, packs plenty of power

Cons: Everything is on the front-panel, low-volume channel imbalance, too bulky to be used as a portable amp, finicky with TRRS jacks



Without referring to "He-Who-Must-Not-Be-Named's" (A.K.A. NwAvGuy) blog, and speaking from my own listening experiences, I really do think the Objective 2 is a great headphone amplifier. No, I don't think this is the amp to end all amps, but it's a dang good one and it only cost me $156 USD (which includes the Triad brand WAU12-200 AC adaptor). In fact, it can be found even cheaper nowadays from the same vendor, JDS Labs, for $140 (including the same adaptor).





What's in the Package?

  • JDS Labs Objective 2 headphone amplifier, wrapped in an anti-static bag
  • 2 removable, rechargeable Tenergy 9 V nickel-metal hydride (Ni-MH) batteries (already installed in the O2)
  • 4 adhesive clear-rubber feet
  • 3-foot long Monoprice mini-USB to USB cable, with gold-plated connectors and a ferrite bead
  • User Manual
  • JDS Labs business card/contact information
  • 2-year warranty free of part/manufacturing defects
  • Triad WAU12-200 AC adaptor (if purchased)





Custom Orders

There are also 3 things you can get customised when your order your O2; all you need to do is fill out the "order notes" section before you make your purchase:






This is the only place where I have major complaints about the O2.

  • Everything is on the front-panel, and the front-panel only
    • 12 VAC AC adaptor plug
    • Power button
    • 3.5 mm output
    • Red LED power indicator
    • Volume potentiometer
    • Gain button
    • 3.5 mm output

Yeah...there's a lot stuff going-on on the front-panel, and the cable management is a mess.


Adding to the mess of stuff on the front-panel, the amp itself is too big (for me) to be considered a portable amplifier. Perhaps for those people who carry around a "portable" bomb rig that is 6-inches thick with 4 different components and paired with a 10 pound open-back Audeze LCD-2 headphone with $500 platinum-coated silver interconnect cables (slight exaggeration here), this amp is trivial in size; but I am not one of those people and I prefer to have a tidy, pocketable portable rig instead.


Kidding aside, the other thing that bothers me with the O2 is the channel imbalance encountered at low volume-levels with the potentiometer. When past the channel imbalance region (~8:30 o'clock position on the potentiometer), the output is kind of loud even with 1.0x gain, especially with sensitive headphones. Because of this, I don't really recommend the O2 for such headphones unless you have a custom gain of less than 1.0, or you use an impedance adaptor.


As a small note, at least with the V-MODA Crossfade M-100's cables, my O2 doesn't seem to like TRRS jacks too much. If I plug it in all the way, I get a mono-like sound coming out of the O2. Pulling out the jack slightly seems to remedy this issue and all is good.


All things considered, the layout of the O2's front-panel is messy and the potentiometer's channel imbalance can be a bit of annoyance for some headphones.


The O2 outside of its case:







From switching between different amps, headphones, and sources I have at hand, the O2 has a very clean-sounding signature as a whole.

  • Bass extension is good with decent texture
  • Midrange is a bit laid back in presentation, but not lacking in detail
  • Treble is well-extended with no roll-off from what I can detect
  • Soundstage is pretty spacious, having both good width and depth
  • Related, but not necessarily correlated to the soundstage, imaging is also very good and I can easily imagine where instruments are in my head
  • Instrument separation is excellent; instruments are well-defined and never muddled together
  • Related, but not necessarily correlated to the instrument separation, instruments have very good detail and nothing sounds muffled
  • There is no background hiss from what I can hear with 1.0x and 2.5x gain options at reasonable volume levels


Q: Is this what neutral sounds like?

A: I have no idea. I'm not a musician, nor do I play any instruments, so I can't say if it sounds coloured or not.


Q: Is this what a "wire with gain" sounds like?

A: Maybe. This relates to the previous question.


Q: Is this what "boring" or "sterile" sounds like, as some have suggested?

A: Not in my book. Different genres of music of all different kinds of mastering sound fine with me. I have yet to encounter a track and exclaim: "wow this amp is so boring! my music sounds so dull and lifeless!" All I can say is that music in general sounds spacious, well-defined, and clear. Though "involvement" in music is purely subjective, I never find myself being uninvolved in my music unless I'm listening to music as background noise.


Q: Will it power X headphone adequately?

A: Yeah most likely. I really enjoyed the LCD-2 with the O2 over other amps I've heard, even though the LCD-2 isn't my favourite headphone of choice. From a pure synergy perspective, I didn't like the HE-500 with the O2 as it had a pretty tizzy treble that made rock tracks not enjoyable for me to listen to. That might be due to the HE-500 itself though, not the O2.


Q: Does it sound bright?

A: Not at all. I don't know where people got that idea from.


 bright, brilliant The most often misused terms in audio, these describe the degree to which reproduced sound has a hard, crisp edge to it. Brightness relates to the energy content in the 4kHz-8kHz band. It is not related to output in the extreme-high-frequency range. All live sound has brightness; it is a problem only when it is excessive.

Comparing different headphones with the O2 and comparing the O2 to different amps, the O2 is definitely not bright to me. It's definitely not dark either for that matter. Maybe with an HD800 or K 701 they sound bright, but the those headphones are bright by nature, so it's not the O2 sounding bright.






All in all, if you can get past the messy front-panel and the channel imbalance at low volume-levels, then I truly think the Objective 2 is a terrific-sounding amp. I like its sound more than other amps I've tried, both desktop and portable amps, and everything just sounds so dang clear and clean to me. As such, the O2 is my current reference amplifier. For $140 USD, I think the O2 is a no-brainer if you're looking for a clean-sounding amplifier and you don't want to spend OVER 9000!!!!! (read: a lot of) dollars on an amp. You might not like the sound of some headphones out of it, but I think it's due to the headphones themselves and not necessarily the O2.





Thank You!

Thank you for taking the time to read or glance over my review! I hope this review helps you in some way or another and if you have any questions, feel free to leave a comment below.


Happy Listening!



Hey miceblue, great review as usual and very informative. I like your style man!
 Great review! 
 Liked your review, will totally steal some of that for my own Amp reviews :D [gathering a song list for amps, not gonna do song by song break down for an amp, but pictures and how it pairs with headphones personally]
So BRILLANT IDEA'S STOLEN <3 Thank you :D [and I did enjoy it ]
Thanks for the review. I've been loving mine since I got it. I'm convinced it's very transparent, but it does seem to have a hint of brightness in the treble with some headphones (not coming from the headphone). Less so than the Magni I previously had. Barely audible and only shows up with bad tracks. I still think it sounds transparent. The real test is spending years with it and seeing if it doesn't alter the stock signature of any of my headphones.
So far I haven't disliked a headphone with the O2 yet (due to the amp) but maybe sometime?
Good review. I've found mine very transparent and excellent, but the rechargeable cells used in mine (made by the now-defunct Epiphany Acoustics) are rubbish and degraded significantly after a few months. I could easily replace them (the housing just pulls apart) but for how often I actually want to transport this thing, there's just no point. This is probably an issue that varies from assembler to assembler, as I doubt the original specs detailed an exact brand/model of rechargeable cells to use.