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Head-Fi.org › Head Gear › Headphone Amplifiers › Desktop Amps › JDS Labs O2+ODAC


100% Positive Reviews
Rated #92 in Desktop Amps


Pros: Transparent, Powerful, Compact, Audibly Silent, Reference Grade Performance

Cons: Aesthetically challenged in some respects, No RCA in or out,

JDS Labs O2 2


The JDS Labs O2 + ODAC combo (and just about every other version) is built into a simple metal enclosure (mine is black) and all of the inputs and outputs, save for the USB input are located on the front of the device. Aesthetically, I don’t love that design decision but I understand it’s one that was likely made due to the O2 being designed originally as a portable (sort of) amplifier, not a dedicated desktop amp.


So the aesthetics aren’t that great but functionally; I don’t take issue with it. In fact, I’m more than pleased with its performance. Besides, I’m not buying audio equipment based on aesthetics; I’m buying it based on performance. And oh boy can the O2 perform. There are certainly prettier amps out there but amps that can perform as the same level as the O2? Well, probably not in the same price range.


First off, this amp is dead silent. Even with my Creative Aurvana 3 IEMs, the most hiss-prone of all the IEMs I own, the O2 is completely silent. Very impressive.


But the best thing about the O2 + ODAC is how they don’t offer any of their own color to the sound. The two of them disappear completely from the signal chain, allowing you to hear your headphones like you’ve probably never heard them before. If you plug in a pair of HD 600s, the O2 + ODAC will sound like the HD 600. The same goes for the ATH-M50, Triple.Fi 10, RE-262 and just about every other pair of headphones and earphones you can think of. The O2 + ODAC are entirely colorless and transparent, allowing for the sonic characteristics of the headphone that’s plugged in to shape the sound.


And that’s what a good amplifier should do, in my opinion, tube amps obviously exempted due to added coloration inherent to their design. A good amplifier should provide ample amounts of power or current to power hungry earphones without altering the sound itself. That’s what the O2 + ODAC does.


JDS Labs O2 1


But before you rush out to buy an O2 + ODAC, thinking they’ll make your headphones sound better, keep in mind what I said before about them being transparent. The O2 + ODAC aren’t going to magically make your iPod earbuds sound amazing but they will allow for just about any headphones or IEMs to reach their full potential. Though some earphones and headphones are easy enough for an iPod to drive on its own, high impedance ‘phones like the 150 ohm RE-262 and 300 ohm HD 600 need the extra power provided by a dedicated amplifier to sound best. That’s what the O2 does. It doesn’t make headphones sound better; it helps them sound as good as they’re supposed to.


A word of warning though. I keep harping on the transparency of this setup for a reason. Namely, the old adage of “garbage in, garbage out” still applies. If your music collection is filled with crappy 128kbps MP3 files you’ve…”obtained” over the years, this amp will not make them sound better. If anything, it will make the flaws even more obvious. Provided you have good enough headphones, of course. But then again, if you’ve got good headphones, I’d imagine you’d be cognizant enough to make sure your music collection is up to snuff.


But I’ve been wrong before.


Anyway, this is a well built, well thought out and high performing amplifier. I’ve got to hand it to He Who Must Not Be Named on Head-Fi (Not Voldemort), as he talked the talk and proved he’s got the engineering chops to walk the walk. The O2 + ODAC is about $300 fully assembled and shipped or $150 each individually (and the stock O2 has the ability to function as a battery powered “portable” amplifier) so they’re a bit pricey for most people but for music lovers, this is an investment that will pay off in spades every time you hit play.


Pros: Small, Transparent, Open Source, DIY Capable

Cons: Outdated

Intro:  JDS Labs, Is an American company based in Collinsville, Illinois. They make headphone amplifiers & DAC’s. Mr. John Seaber is the man behind JDS Labs. We might remember JDS Labs when they produced the popular cmoy-BB amp & later on, their Objective2 which was a game-changing amplifier. JDS Labs also have their own products: C5/D Portable amplifier/DAC, Element desktop Amp/Dac along with their Cmoy BB amp. My profound thanks to Mr.John for arranging a sample unit for my evaluation.


JDS Labs O2 was my first ever headphone amplifier in early days of my Head-Fi days. Enjoyed it a lot, had a wonderful time with it. O2 holds a special place in my ears.


About O2/ODAC:  The Objective2 as we all know, is a very famous beginner level amplifier, has a very neutral sound signature. Few years ago there were not many amps available under a budget. The one’s available didn’t perform good. O2 was designed by a U.S electric engineer “NwAVGuy” in 2010-2011. The O2 amp standalone is portable & battery operated. But take out the battery & you can fit a tiny DAC inslide the same enclosure called ‘ODAC’.


ODAC is the DAC counterpart of the famous O2 amplifier, & was released in 2012. The ODAC was jointly developed by NwAvGuy and Yoyodyne Consulting . Yoyodyne generated ODAC’s  circuit board, and NwAvGuy provided performance analysis. Yoyodyne has remained responsible for all production engineering & distribution. ODAC was certified as Objective by NwAvGuy; Yoyodyne generated the design and controls its manufacturing. The new Rev.B uses SA9023 & PCM5102A, and the Low dropout regulator has been updated to a ceramic stable Analog Devices ADP151 equivalent part. Fixes include: Added 16x vias to USB support pads to improve mechanical strength of mini-USB jack, new improvised circuit board & locked EEPROM to prevent IC failures, fixed USB supply stability, & minor performance improvements. Rev.B now puts out 2.1VRMS power.


Packaging & Accessories: The unit comes packed in JDS Labs stamped strong black cardboard box. It withstood a rough journey across the globe, yet remained in perfect shape. That explains everything. Included accessories:


Power Adapter:  15V AC-AC adapter. The AC-AC adapters help in minimizing flux leakage in the circuit.


USB Cable: Mini USB cable with ferrite bead, Monoprice brand, has very good quality with 28+1P/24+2C AWG gauge, matches very well with ODAC.



Design and Build:  It has an aluminium case, & the unit which I am reviewing is the RCA version (with RCA connection for ODAC) The RCA jacks being connected to ODAC via soldered wires.  The device itself is very small, nimble & has small footprint. Can also be used as portable DAC, as it is self powered. It does not require any drivers & works on low current draw, which is a plus for compatibility with portable android smartphones. Another advantage of O2/ODAC is, you can build one right in your home using basic soldering tools. It's DIY Friendly.




Sound: Both O2 & ODAC are well documented with scientific proofs about the accuracy of sound delivery, so no questions about that. It delivers whatever is fed into it’s system. Using neutral headphones like HD800 or K702 makes the experience bitter due to harsher treble, but with darker sounding headphones like LCD-2, O2/ODAC does a good job. Driving power is fine, though not as powerful as desktop amplifiers. Op-amps can be swapped for a different hearing experience. Take out the 2068D & install a compatible op-amp of your  choice.




Comparison:  I would like to compare the O2/ODAC with Schiit Magni2/Modi2 which costs under 200$. Schiit has improved the original Magni & Modi, now the reliability & sound quality is noticeably better than the original version. Both Magni2 & Modi2 outperform their counterparts O2 & ODAC Rev.B respectively. Modi2 is much more accurate than ODAC plus an added advantage of 24/192 capacity. Modi2 also sounds much cleaner, clearer than ODAC. Magni2 is more powerful than O2 and also delivers higher transparency. As combo, Magni2/Modi2 outperforms O2/ODAC. Schiit combo costs 200$ with additional features & better sound quality, hence Its a value for money deal.



Affordability:  The truth is, O2/ODAC is losing its charm it had few years ago. This is due to tough competition from modern & advanced products with latest designs. Had been NwAVGuy still around, he would have definitely continued developing the O2/ODAC . But sadly he has disappeared from audio community since long back. So I have to conclude that O2/ODAC is now outdated, and as a replacement, Schiit stack serves the purpose under 200$ budget. The O2/ODAC costs about 275$, which is significantly higher than the Schiit combo.

Conclusion:  O2/ODAC though once a benchmark for performance, is outdated. But it still delivers what it was designed for: “Objective Approach with no BS”. O2 & ODAC created tough competition & compelled audio companies to develop affordable devices with much more value to customer’s money. O2/ODAC will slowly fade away, but will always be remembered as the Game Changer.


My tribute to NwAvGuy: The Man behind the Change.




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