[otinkyad]

Has there been a comparison of O2 to Violectric V200?  I've seen some comments where both are mentioned, and some discussion that someone was going to do a comparison (Naim.F.C...?) but haven't been able to find an actual comparison.  Sorry if I've overlooked a review somewhere, I did search a fair amount.

 

[lukeahale]

I see no reason this should be in the Sound Science forum whatsoever.  There was a short discussion that if taken by itself might be, but other than that, I see very little difference in this thread than any other amp review thread. Does 1% of "sound science" override 99% of headphone amp review discussion?. . . not trying to cause a fuss, just not understanding the logic.

 

[everlong]

How does the T50rp(with simple mod) pair with the O2? Will it lack in power for the T50rp?

 

[mikeaj]

Quote:

How does the T50rp(with simple mod) pair with the O2? Will it lack in power for the T50rp?

It should get something like 5-6V cleanly into something with about 50 ohms impedance.  That should be way plenty of power even with plenty of mods.  IIRC maverickronin (or who else was it?) has some modded T50RP and the O2, so maybe you can ask him.

 

[wje]

Quote:

How does the T50rp(with simple mod) pair with the O2? Will it lack in power for the T50rp?

I'm using my T50RPs (modified) with the O2 amp - as well as some other amps, too.  However, the O2 pairs really well with the Fostex headphones after modifications (which tend to make the T50RP less efficient than when stock).

 

[upstateguy]

Quote:

I love the O2 amp.  However, last evening, I had been using my HifiMAN EF-2A for about an hour and getting acclimated to the sound - with my Fostex T50RPs.  I then took the headphones up to bed, so I could go to sleep.  I noticed quite a difference in the sound signature.  Considering the O2 is an amp designed to not color the sound (as is the intent of most amps), I realized that some color can be good.  In that case, the HifiMAN had me quite impressed for a hybrid.  I need to run it this weekend with my HifiMAN headphones and see how it compares to the O2.  I still won't pull my O2 amps from use, though.  They do a great job, too.

Here's an experiment for you.
 
See how closely you can EQ your O2 to the sound signature of your EF-2A. 

 

[wje]

Quote:

Here's an experiment for you.
 
See how closely you can EQ your O2 to the sound signature of your EF-2A. 

That's a good idea.  I'm assuming that you mean using the EQ on the iTunes side to set the EQ into the song, or set one of the EQ defaults and save it to the player and see I can change the sound more like the O2.  I'm capable of doing that, but for the moment, I'm just appreciating the differences between the two - as I think they are good at complimenting each other.  I also have the C&C BK portable amp that I could try again, too.  It would be interesting to see / hear how it compares in the mix with the O2 and EF-2A amps.  The C&C amp does have some adjustments that can be applied on the amp itself - a bass boost, and a spatial adjustment, where you can use the switch to slightly open up the sound stage of your music a bit.
 
It's all fun, though.
 
 

 

[maverickronin]

Quote:

How does the T50rp(with simple mod) pair with the O2? Will it lack in power for the T50rp?

It should be fine.  My source and gain configuration currently give a maximum of 5Vrms and even with ReplayGain and some EQ the O2 still has plenty of headroom.
 
When watching movies with a 5.1 to binaural DSP I turn the LFE channel up a ton to try and make up for the fact that I can't use a sub or speaker system and can sometimes crank the O2's volume to the max that way but with normal music I never come close to doing that.

 

[upstateguy]

Quote:

That's a good idea.  I'm assuming that you mean using the EQ on the iTunes side to set the EQ into the song, or set one of the EQ defaults and save it to the player and see I can change the sound more like the O2.  I'm capable of doing that, but for the moment, I'm just appreciating the differences between the two - as I think they are good at complimenting each other.  I also have the C&C BK portable amp that I could try again, too.  It would be interesting to see / hear how it compares in the mix with the O2 and EF-2A amps.  The C&C amp does have some adjustments that can be applied on the amp itself - a bass boost, and a spatial adjustment, where you can use the switch to slightly open up the sound stage of your music a bit.
 
It's all fun, though.
 
 

 

Actually I was thinking you would be using the EQ on something like foobar and adjusting the O2 until it approximated  the sound signature of your EF-2A.
 
I doubt you could successfully adjust any of the other amps to sound like an O2 because they lack the transparency and resolution.
 

 

[Satellite_6]

With stock tubes the EF2A is rather bright and distorted. . . a solid state amp should sound noticeably clearer. 

 

[Zsubbo]

I had both, (the O2 and the EF2A), the O2 is noticeably better, they are not in the same league IMO, but you can start tube rolling, and can find out, if it's your thing or not. (BTW, some cheap Chinese amp from eBay, like the Indeed or the Bravo would be better for this IMO)

 

[wje]

 
Quote:

Actually I was thinking you would be using the EQ on something like foobar and adjusting the O2 until it approximated  the sound signature of your EF-2A.
 
I doubt you could successfully adjust any of the other amps to sound like an O2 because they lack the transparency and resolution.
 

 
Ahh, I see.  Yes, that would be a good option.  Though, I don't think too highly of the built-in DAC on the EF-2A.  It will really take quite a bit of EQ work to get it corrected.

 
Quote:

With stock tubes the EF2A is rather bright and distorted. . . a solid state amp should sound noticeably clearer. 

I'm assuming I'm running the stock tubes, or so it was indicated to me by the seller.  I haven't found the EF-2A to be bright at all.  I used to be a big fan of the Grado house sound, so I do realize when I'm listening to something with a lot of detail -- above and beyond the natural detail of the O2 amp.  I haven't pushed the EF-2A to the point where my ears could detect distortion - then again, by the time it reached that level, it might be too late to prevent damage.
 
 
Quote:

I had both, (the O2 and the EF2A), the O2 is noticeably better, they are not in the same league IMO, but you can start tube rolling, and can find out, if it's your thing or not. (BTW, some cheap Chinese amp from eBay, like the Indeed or the Bravo would be better for this IMO)

I think it depends on a lot of variables.  The EF-2A can be found at some pretty great prices that can be a bit less than the O2 amplifier itself.  It also depends on one's listening desires.  Some may prefer the tube sound over the solid state sound of the O2. 
 
I'm not here trying to defend the EF-2A because I own one, but rather, point out my personal experiences with it by purchasing one that was used and has some time logged on it.  Also, I feel my observations are also objective regarding the Objective2 amplifier, because I own (2) of them.  So, I have no reason to be hatin' on the O2. 

 
 

 

[essencez]

Objective2 is a very special amp. I am currently awaiting the adapter to see if it'll dominate my long time favourite portable, RSA P-51 Mustang. Sure the O2 isn't as portable but the fact it can run on batteries alone is a huge plus. Mainly the reason why I got it.
 
Using it with diyMod LOD + DT48e showed even on a 1x gain setting the amp packs a lot of punch for its size. I am testing with so far, uncharged version of the amp straight from JDS Labs too. Hopefully within the next few months the Objective DAC gets released and meets the high expectations set by the O2 amp. And google Android developers can finally fix the lack of support for native audio DAC devices. Then HiFi portable setups won't be monopolized by Apple and the limited amount of digital out devices.

 

[gkanai]

Hi everyone,
 
I'm based in Japan (100 V, 50 Hz / 60 Hz) and am interested in an O2.
 
I asked Voldemort what power adapter I should get and he said:
 
Quote:

If you can find a 120 VAC to 18 VAC adapter you can use an adapter plug and run it on 100 volts and you will get 15 VAC output. Even a 16 VAC will work OK like the ones in the parts list.

 
I want to be sure I get what I need. Can someone help me identify exactly which Mouser part number is the one I want? Thank you in advance!

 

[sonitus mirus]

In Japan, you need an adapter plug so the US power adapter can get juice from the wall.  
 
Something like this will suffice:
 
http://www.amazon.com/Adapter-America-Japan-Grounded-Polarized/dp/B001FDC72A
 
You can then use an AC adapter from Mouser (model number 412-218054) that will output 18VAC with .5A with a nominal input voltage of 120VAC.
 
http://www.mouser.com/ProductDetail/Xicon/412-218054/?qs=DSkiUaeR7Kd3FFc9bqoJoQ%3d%3d
 
With 100VAC, you should get 15VAC output and just over 400 mA, right in the wheelhouse for the O2.
 
Any similar adapter will work, just be sure the output of the adapter is AC and not DC.  DC output is much more common, and it would be easy to make the mistake.
 
(Edit: removed poor suggestion)