[ostewart]

[size=medium] JDS Labs Assembled O2 Black Edition Review[/size]
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[size=medium] I would like to thank JDS Labs for sending me this sample for review, and to use as my reference amp.[/size]
[size=medium] I will write as honest a review possible, supposedly this amp needs no burn-in as there are no capacitors in the output stage, even so it has quite a few hours on it.[/size]
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Photos by Felix Speller:
www.felixspeller.com
www.flickr.com/felixspeller
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[size=medium] Gear Used:[/size]
[size=medium] IPod Classic 160gb (rockboxed) > DIY Silver LOD > JDS Labs O2 > lots of different headphones[/size]
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[size=medium] Packaging, Build Quality and Accessories:[/size]
[size=medium] Packaging, well JDS are a more DIY company, so what you get is the amp, instructions and some rubber feet. I didnt get an AC adapter as i'm in europe, so i had to buy one. I think the package is simple but effective, the package was well protected by bubble wrap and the amp comes in an anti-static bag. Dont expect fancy packaging, but do expect great value and customer service.[/size]
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[size=medium] Build quality is excellent, the metal enclosure feels very solid, the on/off and gain switches are spring loaded, the volume pot is smooth to operate and the input and output jacks are stiff and good quality, the amp is hand assembled in America, and you can tell by the quality of it, I did open it up to see the board, and the solder joints are great, and it is very neatly made.[/size]
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[size=medium] I got the new black edition which looks better than the standard version in my opinion, i also got custom engraving which they provide free of charge with any order, and the engraving is expertly done. The edges of the amp are slightly rounded so it feels good in your hands.[/size]
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[size=medium] Design:[/size]
[size=medium] I will say a little about the design, this was not really made to be portable, more transportable as the size is a bit big to fit in your pocket but it does have 2 rechargable 9v batteries inside so it works without being plugged in, and the battery life is supposed to be around 8-10 hours.[/size]
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[size=medium] The amp has all inputs and outputs on the front, and I think that in the future they may make a full desktop version, as this only has 3.5mm input and output, I would like to see RCA inputs on the back, with the AC jack on the back too, with only volume, gain and headphone out on the front.[/size]
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[size=medium] This amp comes with variable gain, the standard is 2.5x and 6x, however you can customise this when you order it, I find the stock gain to be almost perfect, I think 1x and 6x would be good.[/size]
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[size=medium] It has a built in headphone protection circuit which stops it outputting too much power into your headphones, also you can leave it plugged in and it does not get hot amd the batteries get trickle charged so no need to worry about damaging the batteries or the amp. When turning the amp on there is a slight audible click and when powering down there is a slight thud, but not loud or anything capable of damaging the drivers of the headphones.[/size]
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[size=medium] I really think a lot went into the design of this amp, its a really nice shape and size, the only thing I would change is the layout of input/outputs, but that means more design and tweaking.[/size]
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[size=medium] Sound:[/size]
[size=medium] A lot has already been said about the O2, so I can't really add much. What I will say is that this amp is incredible, it is transparent, what goes in comes out clean and purely amped, not modified in any way.[/size]
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[size=medium] You can plug any headphone in and its just so clean and clear, this amp is also very powerful, I had the chance to test it with the HD650, HD700, T1, HE6 and more... It managed to drive all of them, the T1 sounded excellent out of the O2, the HE6 was powered nicely with the O2 but I did prefer the HE6 out of a nice tube amp, the HD700 also sounded great out of the O2 and it had no problems with power.[/size]
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[size=medium] With the T1 I had to use high gain, and the volume was about 10 o'clock on the pot, but it had plently of power and the sound produced was incredible.[/size]
[size=medium] I was impressed by the power such a small amp can produce, and also the clean sound it produced, I really think this amp can drive most headphones quite well, and pairs well with most headphones as it let's the music shine through, not the amp colouring the sound.[/size]
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[size=medium] I think that anyone looking for a budget amp, or even just a great transparent amp that can power nearly all headphones should check this out, it really is excellent value for money, the build quality, the sound, the power, everything is just very well thought out.[/size]
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[size=medium] Thank you for reading[/size]
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Tracks Used:
Skrillex – First Of The Year (Equinox) (320kbps MP3)
Paramore – Franklin (320kbps MP3)
Diana Krall – The Girl In The Other Room (FLAC)
Deolinda – Passou Por Mim E Sorriu (live) (ALAC)
Suicide Silence – Unanswered (FLAC)
Massive Attack – Angel (ALAC)
Eat Static – Dzhopa Dream (ALAC)
The XX – Crystalised (FLAC)
Funeral For A Friend – Bend Your Arms To Look Like Wings (ALAC)
Mumford & Sons – Little Lion Man (FLAC)
The Scene Aesthetic – Humans (259kbps MP3)
A Hero A Fake – Swallowed By The Sea (254kbps MP3)
Vivaldi – The Four Seasons, Spring Allegro (ALAC)
Johnny Craig – Children Of Divorce (161kbps MP3)
Deadmau5 + Kaskade – I Remember (Caspa Remix) (320kbps MP3)
Black Uhuru – Utterance (ALAC)
We Are The In Crowd – Never Be What You Want (226kbps MP3)
Silverstein – Discovering The Waterfront (320kbps MP3)
Concept Of Thought – Our Thought (FLAC)
Nirvana – Something In The Way (Unplugged) (ALAC)

 

[wolfetan44]

You got rubber feet with your O2? I didn't.

 

[TheKillerPiglet]

Randomkid,
I see you also own the C421, could you contrast the two, especially with the T1?
 
KP

 

[ostewart]

T1 is driven better with O2 as the O2 has more power and also the C421 is not as transparent as the O2, it sounds slightly warm in comparison. C421 wasn't made to drive the T1 really.

 

[antberg]

Nice thoughts Random,finally my second shipping may come home in a week or less,i hope.My HD650 will be very happy,haha!
Quote:

You got rubber feet with your O2? I didn't.

Well,maybe they did send them as gift,i did ordered one pair for the O2 and another pair for the ODac.But i did paid for them nonetheless,just a 2 dollars each,though.

 

[TheKillerPiglet]

Quote:

T1 is driven better with O2 as the O2 has more power and also the C421 is not as transparent as the O2, it sounds slightly warm in comparison. C421 wasn't made to drive the T1 really.

Thank you. I am considering a"'tweener" amp to carry with my laptop and will keep this in mind.
 
KP

 

[ostewart]

I got rubber feet with my O2 and C421, I thought they came as standard, but I did put different feet on my O2, slightly bigger as it's not really portable so it doesn't matter.

KP the O2 would be perfect as a transportable for your laptop

 

[ostewart]

I didn't like the HD650 out of anything, but the O2 drives them fine and actually brings out some detail in them.
What sounds good is the music being amplified not the amp colouring the sound

 

[spaark]

Quote:

I had the O2 & the HD650's at one point and I found that the O2 was terrible with them. I don't know why but people love to claim that this amp sounds great with everything without really explaining what "sounds great" means. Anyhow, I did like how the O2 drove my HD448's. It's a decent amp for some kinds of headphones.

What's important to remember is that the O2 is transparent. It let's you hear headphones the way they were meant to be heard.

 

[AKG240mkII]

Quote:

I had the O2 & the HD650's at one point and I found that the O2 was terrible with them. I don't know why but people love to claim that this amp sounds great with everything without really explaining what "sounds great" means. Anyhow, I did like how the O2 drove my HD448's. It's a decent amp for some kinds of headphones.

 


Since the amp is 'Transparent' ..
Don't you think it's the sound-signature of the HD650's causing your 'problem' ??

 

[HamilcarBarca]

Quote:

Quote:

I had the O2 & the HD650's at one point and I found that the O2 was terrible with them. I don't know why but people love to claim that this amp sounds great with everything without really explaining what "sounds great" means. Anyhow, I did like how the O2 drove my HD448's. It's a decent amp for some kinds of headphones.

 

Since the amp is 'Transparent' ..
Don't you think it's the sound-signature of the HD650's causing your 'problem' ??

 
Either that or the source material. I don't know why people complain that a transparent amp sounds bad. They can't even hear it.

 

[MrMateoHead]

Great Review -
 
I have the black O2 and now the Black ODAC as well. It costs a bit more, but I like the idea that I can use them as separate components in the future if I wish. It would be nice to move the jacks around, and maybe even redesign the amp so that the ODAC could easily "dock" when its mating to the O2.
 
I can confirm that the battery life is pretty close to all-day long, but I don't like how the amp just stops playing when the batteries quit - a low battery indicator wouldn't be a terrible thing. A power light on the ODAC would also make sense, should one have an issue with it (like, forgetting to change their settings in windows, but assuming that their ODAC is "broken").
 
I can also confirm that the sound quality is just above and beyond what I expected. There is ZERO noise emitted from the pair, at max volume, nothing playing. Total black background. That said, it took a few minutes to get used to the new sound, as my on-board audio, while noisier, might have been a touch on the "warm" side. That and, the 2V output of the ODAC is noticeably stronger than the 1V computer. There was a "thinness" to my ears which reminded me of hearing my HE-400s for the first time. Now the spaciousness and black background are just awesome.
 
If you spring for the pair, I would recommend considering a gain of 1X and 6.5X (for non-ODAC sources like phones or Mp3 players). Given the relative variety of source inputs that you might use with the O2, it is a good idea to have fairly low, and fairly high gain modes. 2.5X is probably higher than needed with the ODAC, but not high enough for weaker sources.

 

[ostewart]

Thanks for the comment, yes it takes a while to get used to if your used to a warmer source.

Look out in February for more from me on JDS labs products, including the ODAC

 

[wolfetan44]

Wait, what do I have to do in windows to make my ODAC work? I thought it was just plug in and use.

 

[ostewart]

It should be plug and play, but sometimes you need to open your audio devices controls and select ODAC as the default audio driver/device instead of pc speakers or normal headphones out.