Quick review of Objective 2
May 31, 2012 at 12:13 AM Thread Starter Post #1 of 26

mechgamer123

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Hello fellow Head-Fier's, this is my first review, so please be nice :)
Sources used in review:
Ipod Classic 6G 80GB
Fiio L9 LOD
Headphones:
Brainwavz B2
Yamaha EPH-100
Sennheiser HD600
 
I opened my iPod a few weeks ago to replace the scratched up casing and the battery. I also replaced the headphone jack, which started only making sound out of 1 channel about a month later. So I used this excuse to buy myself an amp so I could listen to my music again through my iPod Classic. 
smily_headphones1.gif

 
First Impressions:

The Amp definitely feels good in the hands, and as you can see, it has no trouble powering the B2s without moving the dial above 9 o'clock.
On low gain, I usually have the volume somewhere between 10 o'clock for "loud" music and 12 o'clock for "quiet" tracks with my HD600s, which really aren't that hard to drive either.
 
Build Quality: 
The enclosure is made out of Aluminum and the front panel is made out of bamboo (This seller has many different customization options available, this is just what I chose.)
The enclosure looks very durable and professional for something that was handmade.
 
Portability:
Not as bad as I thought it would be. The amp is about 1.7 iPod classics (The width of the iPod) wide and about 1.1 classics (The length) long. Still not really portable though unless you have cargo shorts.
Also, the L9 cable really sucks to use with the O2 because the cable is terminated out the right of the iPod dock, when it should be terminated out the Left to work well with the O2.
 
Sound Signature:
First of all, here is NWAVguy's frequency response graph for the amplifier:

 
This is the part of the review I want to update. I thought it made my music sound a bit thin, but I have since then attributed this to changing tips from comply foam to silicone.
This amp is very neutral. It does not emphasize any frequency range, nor does it mask any frequency range. This is exactly what I looked for when choosing an amplifier and this does the job nicely.
With a neutral source (like the classic) and neutral amp (like this) it allows for all frequency emphasis (or the lack thereof if you want a truly "neutral" setup) to be done through the headphones.
For this reason, I would not recommend these with a flat or bright headphone because of the fact that it will make the treble regions seem too bright for people used to "warm" amplifiers.
S.Q: 10/10
Tl;DR: I won't be buying another amp for a while now.
 
Amplification power:
Obviously, it's able to power my IEMs with ease. I feel that they do make the B2s sound better than being driven straight from an iPod.
It also powers my HD600s without struggling whatsoever.
 
Recommended Headphones: 
Due to the flat sound sig of the O2, I would guess based off my experiences with the B2s, which have significant treble spikes, that a lot of headphones with large treble spikes, or general emphasis on the treble will not sound as full and balanced as they would coming from a warm amplifier.
 
Final Notes: I consider amps to be an intermediate step in being able to power bigger and better headphones, and going from no amp to this is a huge improvement. Also, in my opinion, an amplifier should not add distortion. Only amplify sound to allow you to use headphones with higher power requirements.
Finally, here's a video of the O2 powering 1 PA/Concert Speaker. I didn't feel like setting up the other one in parallel, and I didn't have any 6.3mm mono cables either.
http://www.youtube.com/watch?v=WwD0unmTZ-Y
I'm out.
 
May 31, 2012 at 6:49 PM Post #5 of 26

mechgamer123

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May 31, 2012 at 7:31 PM Post #6 of 26

KimChee

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Thanks for the review, I've been looking into getting one of these.  
 
Jun 2, 2012 at 2:16 PM Post #8 of 26

MattTCG

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Thanks for the impressions. I'd consider the combo unit due out soon. Curiosity kinda has the best of me on this one.
 
Jun 3, 2012 at 3:38 AM Post #9 of 26

the search never ends

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Pretty good review, I don't own one but have had enough time with it for my own impressions.  For this being your first amp in a while you hear it like I do, it's fairly transparent, but a little dry, and sounds more like a portable amp than a desktop amp. The dac used  your classic isn't as good as a dedicated unit like the one that will be out soon to fit in the amp. I just hope the dac isn't as cold sounding as the amp. I know nwav guy is always defending his amp, and I think it's fine for it's cost, but he's proven that measurements aren't the holy grail, at least in absolute terms. Like his measurements, all science is theoretic.
 
I am looking forward to his desktop amp, hoping it improves some on the soundstage and body from the mids down, and keeps that dead silent background.
It will be a huge boom for budget minded people if his desktop amp combined with his dac hit the mark and I hope they do.  As it stands, I prefer the sound out of the 180 dollar Audinst MX1  over the O2 with a HRT 2, the 2+ closes the gap, but I can't see people spending 300 on a dac for a 150 dollar amp, just my 2 cents. your review was more objective than my comments here. My preferences impede me from being any less subjective.  Owning/hearing a bunch of audio gear is a mixed result, not many can resist the urge to keep on buying gear once they get on the slope.
 
Thank you for the review
 
Jun 3, 2012 at 10:40 AM Post #10 of 26

stv014

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Quote:
Originally Posted by the search never ends /img/forum/go_quote.gif
 
I am looking forward to his desktop amp, hoping it improves some on the soundstage and body from the mids down, and keeps that dead silent background.

 
As far as I know, the desktop version will be mostly the same (other than the power supply), and the changes will be focused mainly on improving the usability as a desktop amplifier. But I guess that will not stop people from hearing differences
normal_smile%20.gif

 
Jun 3, 2012 at 8:33 PM Post #11 of 26

the search never ends

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I can't argue that people will hear differences no matter what, but if that stays true, I won't want a listen, I'll continue to refer the budget minded to the Audinst
Quote:
 
As far as I know, the desktop version will be mostly the same (other than the power supply), and the changes will be focused mainly on improving the usability as a desktop amplifier. But I guess that will not stop people from hearing differences
normal_smile%20.gif

 
Sep 5, 2012 at 12:14 AM Post #13 of 26

antberg

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Guys just a question:I am looking to buy a O2 units for myself as i am (as always) tight on budget and it seems that this great amp could be a good start ,even if a basic one,to drive a pair of HD650 that i will try to buying soon.So i have been looking in my town for an adapter and the only one i found was 14Vac with 500 Mah.
 
Does someone with a similar power adapter have experienced some overheating of the unit,taken the amperage?or it is best to find one with 200/300 Mah?
Thanks for the input guys.
PS:To be honest i am in doubt if i have to get more patience in waiting the awaited ODA....
 
Sep 5, 2012 at 6:40 AM Post #14 of 26

stv014

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Quote:
So i have been looking in my town for an adapter and the only one i found was 14Vac with 500 Mah.

 
Do you mean 500 mA (AC RMS) maximum current ? If yes, it should be fine for your HD650's.
 
Sep 5, 2012 at 7:13 AM Post #15 of 26

MattTCG

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After a days audition, I have found the following:
 
1. The o2 is bested by both the Fiio e09 and ld1+. 
 
2. The sound on the o2 becomes somewhat thin and bass looses impact and texture.
 
3. It had no problem with power and drove my he400, he500 (borrowed) and modded fostex well.
 
I had high hope for this little amp. Sound stage was similar to the other amps but the treble was also somewhat bright and fatiguing to my ears. I also didn't like the location of the connection on the front of the unit. All of my testing was done with an odac by Audio Poutine. It has RCA jacks on the back of the unit which I like. Not for me...
 

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