mechgamer123
Headphoneus Supremus
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.
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.
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.
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.
