[snakesoul]

As you would need to plug the O2 into the SB-Z's headphone output jack, you would be doubling amping (may or may not affect audio quality).
Where as if you sold off the HD558s, you could get some AKG K612 Pro headphones, 114 GBP.

I just feel that once you have the SB-Z, it's a waste of cash to buy the EPH-02, unless you plan on buying low impedance headphones, like 32-Ohms or less.

Hi PurpleAngel,
Thanks for your patience and help.
I'm really leaning for O2 + Asus xonar dx, since i think it's a better option for long term use, and also O2 will provide me a better experience with its lowest output impedance (feel free to correct me if I'm wrong.)
Hmm selling 558's it's not a chance for now, since I only have them for less than a week..If only I knew I could have bought a new superlux 681 from a friend of mine (I know I can't compare comfort between these two but since it has lower ohms maybe it was a better bet? )
Thanks in advance,

 

[cel4145]

The EHP-O2 is down to £77.99 now (not sure what shipping would be for you). Not a heck of a lot more than the Soundblaster Z. I think it would be worth the wait to save up for the O2 since you already have the DX. It's a fantastic headphone amp for the price

 

[PurpleAngel]

Hi PurpleAngel,
Thanks for your patience and help.
I'm really leaning for O2 + Asus xonar dx, since i think it's a better option for long term use, and also O2 will provide me a better experience with its lowest output impedance (feel free to correct me if I'm wrong.)
Hmm selling 558's it's not a chance for now, since I only have them for less than a week..If only I knew I could have bought a new Superlux 681 from a friend of mine (I know I can't compare comfort between these two but since it has lower ohms maybe it was a better bet? )
Thanks in advance,

 
I think the O2 & Xonar DX are a great combo.
O2 is a good choice for driving the HD558s.
The HD558s come with a black rubber tape on the insides of the cups that cover 40% of the air holes.
Removing the black rugger tape should improve surround sound and treble, but it might void the warranty.

 

[snakesoul]

   
I think the O2 & Xonar DX are a great combo.
O2 is a good choice for driving the HD558s.
The HD558s come with a black rubber tape on the insides of the cups that cover 40% of the air holes.
Removing the black rugger tape should improve surround sound and treble, but it might void the warranty.

Well i also think it will be a great combo. Thanks for your help.
Meanwhile, until i get it (i already e-mail them to ask how much it will cost to deliver it to my country), can i still use the DX+558's? I know i can use them, but my question is, does it somehow damage the headphones? So far i can only stand the volume low (sound about 18% to 25% on windows\asus driver)
My settings are:
Windows playback devices - 7.1 -
Asus xonar audio center:
channels - 8
Sampling rate - pcm 44.1Khz
Headphones
EQ - default
 
I'm not sure if i like so much dolby headphone with this headphones, since it becomes louder and sometimes confusing...
Are my settings correct for gaming?
Also on windows playback options, should i put 5.1 for sorround sound or let it be like it is already?
Or should i set it to 2 channels only and apply dolby headphone with this option?
 
Thanks in advance and all for your help,

 

[PurpleAngel]

 
Well i also think it will be a great combo. Thanks for your help.
Meanwhile, until I get it (i already e-mail them to ask how much it will cost to deliver it to my country), can i still use the DX+558's? I know i can use them, but my question is, does it somehow damage the headphones? So far i can only stand the volume low (sound about 18% to 25% on windows\asus driver)
My settings are:
Windows playback devices - 7.1 -
Asus Xonar audio center:
channels - 8
Sampling rate - pcm 44.1Khz
Headphones
EQ - default
I'm not sure if i like so much Dolby headphone with this headphones, since it becomes louder and sometimes confusing...
Are my settings correct for gaming?
Also on windows playback options, should i put 5.1 for sorround sound or let it be like it is already?
Or should i set it to 2 channels only and apply dolby headphone with this option?

Plugging the HD558 directly into the Xonar DX will not damage the HD558, your ear will get damaged long before the HD558s.
The Xonar DX's high impedance will just give the HD558s a bloated (louder, less detailed) bass.
I would say to leave the sample rate at 24-bit/48Khz.

 

[snakesoul]

So i've been reading some more and doing some research, and before i order, i would like you to help me please:
 
1 - So from what i've been reading, sennheiser hd 558, are between 50 (can go) to 80 Ohms, so from my math it would be: 50/8= 6,25 Ohms to 80/8= 8Ohms, is this correct?
If so i would benefit from O2 amp since output impedance is >0.5.
Creative output impedance are +/- 22Ohms, so there's a big difference between the output impedance from my cans and the output from the card (around 15.75 Ohms) is this what people call damping? Correct me if i'm wrong using this terms...
What this difference values do the sound to sound\headphones? 6,25 vs 15,75
2- As i'm leaned to order O2, do i have to buy some cables to connect to my sound card? or is it provided in the box?
3- Since i'm going to use it almost for gaming in my pc, can i have it always plugged in to the wall, or i have to disconnect it when i turn pc off? (sorry for this dumb question, but i had to ask..)
4 - I read creative cards are better for gaming (sound itself is more pleasant), but xonar's are better for music.. is this correct? I know i can't have both worlds, but since i do 80% gaming, 20% videos on youtube and music, i don't want to have a good gaming card and a bad for everything else...
Any help will be appreciated
5- Is there a reason why dolby headphones sound to me like i'm in a tunnel?

 

[kraken2109]

Keep the Xonar DX as a DAC and add an amp like the Magni for £100
http://www.electromod.co.uk/product-detail.asp?P=42

 

[snakesoul]

  Keep the Xonar DX as a DAC and add an amp like the Magni for £100
http://www.electromod.co.uk/product-detail.asp?P=42

Hi kraken,
 
From you POV which one is better? Magni or O2?
Wow as much as i love the looks of magni, it's too expensive to send to my country (£40?\66$)...

 

[PurpleAngel]

  So i've been reading some more and doing some research, and before i order, i would like you to help me please:
 
1 - So from what I've been reading, Sennheiser hd 558, are between 50 (can go) to 80 Ohms, so from my math it would be: 50/8= 6,25 Ohms to 80/8= 8Ohms, is this correct?
If so i would benefit from O2 amp since output impedance is >0.5.
Creative output impedance are +/- 22Ohms, so there's a big difference between the output impedance from my cans and the output from the card (around 15.75 Ohms) is this what people call damping? Correct me if I'm wrong using this terms...
What this difference values do the sound to sound\headphones? 6,25 vs 15,75
2- As I'm leaned to order O2, do i have to buy some cables to connect to my sound card? or is it provided in the box?
3- Since I'm going to use it almost for gaming in my PC, can i have it always plugged in to the wall, or i have to disconnect it when i turn pc off? (sorry for this dumb question, but i had to ask..)
4 - I read creative cards are better for gaming (sound itself is more pleasant), but Xonar's are better for music.. is this correct? I know i can't have both worlds, but since i do 80% gaming, 20% videos on youtube and music, i don't want to have a good gaming card and a bad for everything else...
Any help will be appreciated
5- Is there a reason why Dolby headphones sound to me like I'm in a tunnel?

 
It's preferred to have the headphones to have 8 to 10 times the impedance (Ohms) of whatever source your plugging the headphones into.
( I can plug my 600-Ohm headphones into my O2 amp (.5-Ohms), making the headphones have 1200 times the impedance, which works fine).
With the SB-Z's 22-Ohms, the HD558 (50-Ohms) are only 2.27 times the impedance of the SB-Z, not perfect, but it still sound fairly good (I've tested it).
With the O2 (EPH-02), DX combo, the only cable you would need is a 3.5mm to 3.5mm cable. I did not see a cable listed with the EPH-02.
You can leave the O2 (EPH-02) plugged into the wall 24 hours a day, just use it's power switch (on the front) to turn it off when not in use.
The Creative cards seem to have the edge for FPS gaming (there are a few who prefer Xonars)
Maybe around 5 or 6 years ago Xonars would be considered better for music, but nowadays the Creative Titanium-HD and Z series and Xonars are really about equal for music/sound quality (for a driven price range).
 
These threads are good for asking about gaming
http://www.head-fi.org/t/534479/mad-lust-envys-headphone-gaming-guide-update-3-29-2014-ultrasone-hs-15-added-edits
http://www.head-fi.org/t/593050/the-nameless-guide-to-pc-gaming-audio-with-binaural-headphone-surround-sound

 

[PurpleAngel]

 
Hi kraken,
 
From you POV which one is better? Magni or O2?
Wow as much as i love the looks of magni, it's too expensive to send to my country (£40?\66$)...

 
Personally I see the Magni and O2 as about equal.
The 02 has the advantage that it can also work off it's two 9V batteries.

 

[snakesoul]

   
It's preferred to have the headphones to have 8 to 10 times the impedance (Ohms) of whatever source your plugging the headphones into.
( I can plug my 600-Ohm headphones into my O2 amp (.5-Ohms), making the headphones have 1200 times the impedance, which works fine).
With the SB-Z's 22-Ohms, the HD558 (50-Ohms) are only 2.27 times the impedance of the SB-Z, not perfect, but it still sound fairly good (I've tested it).
With the O2 (EPH-02), DX combo, the only cable you would need is a 3.5mm to 3.5mm cable. I did not see a cable listed with the EPH-02.
You can leave the O2 (EPH-02) plugged into the wall 24 hours a day, just use it's power switch (on the front) to turn it off when not in use.
The Creative cards seem to have the edge for FPS gaming (there are a few who prefer Xonars)
Maybe around 5 or 6 years ago Xonars would be considered better for music, but nowadays the Creative Titanium-HD and Z series and Xonars are really about equal for music/sound quality (for a driven price range).
 
These threads are good for asking about gaming
http://www.head-fi.org/t/534479/mad-lust-envys-headphone-gaming-guide-update-3-29-2014-ultrasone-hs-15-added-edits
http://www.head-fi.org/t/593050/the-nameless-guide-to-pc-gaming-audio-with-binaural-headphone-surround-sound

 
 

   
Personally I see the Magni and O2 as about equal.
The 02 has the advantage that it can also work off it's two 9V batteries.

Thanks for your help PurpleAngel,
 
I'm going to read those links you posted, but i think i'm going to order the O2. I think it's a best bet for me and my needs.
If only i didn't had xonar dx i would order creative's, and i think it would be a good bet also..
I liked how magni looked, but O2 it have also a great look (and i'm more interested in the sound actually, than the looks...)
For the cable, i think i'm going to ask to Oliver if there's some cable to connect to, if not i'll see if i order one.
 
Thanks in advance for all your help

 

[snakesoul]

Sorry for the late reply,
 
 
So i ordered the O2 and just got it.. First impressions, it's a small and well built amp (well can't actually compare to any other since it's my first one).
I did feel the difference between with amp and without it (gaming and music for the 5 minutes i turned it on).
Not a big difference, but i think with time my ears will get used to it.
But know i got some questions i would like you to help me solve:
1- In the package there was a sticker saying i should charge it for 8 to 12 hours before first use, but since i'm going to plug it all the time is there a problem? Is the battery going to damaged in some way if i don't do it?
2- How do i set the volume up pc vs amp? Leave it on 50% in windows and control with amp? or is it just personal preference? 
Thanks in advance,

 

[PurpleAngel]

  Sorry for the late reply,
 
 
So i ordered the O2 and just got it.. First impressions, it's a small and well built amp (well can't actually compare to any other since it's my first one).
I did feel the difference between with amp and without it (gaming and music for the 5 minutes i turned it on).
Not a big difference, but i think with time my ears will get used to it.
But know i got some questions i would like you to help me solve:
1- In the package there was a sticker saying i should charge it for 8 to 12 hours before first use, but since I'm going to plug it all the time is there a problem? Is the battery going to damaged in some way if i don't do it?
2- How do i set the volume up PC vs amp? Leave it on 50% in windows and control with amp? or is it just personal preference? 
Thanks in advance,

 
The O2's AC can be left plugged in 24/7, the O2 is designed to stop charging the batteries once the batteries are fully charged.
Best to have the source (PC) set to as high a volume as possible, setting it to 100% is not always possible, but setting PC volume to ar least 75% should do the job.
So turn the O2's volume all the way down (or off), then turn up the volume control (75%-100%) on the PC, then slowly turn up the volume knob on the O2, until you find the volume level you like.

 

[snakesoul]

Hi PurpleAngel,
 
Thanks you so much for your help and advice.
One more question i forgot to mention, how about the "gain" button? Should i leave it on or off? The sound difference is huge for me, between turning it on or leave it off... The sound becomes much more louder...

 

[PurpleAngel]

  Hi PurpleAngel,
 
Thanks you so much for your help and advice.
One more question i forgot to mention, how about the "gain" button? Should i leave it on or off? The sound difference is huge for me, between turning it on or leave it off... The sound becomes much more louder...

With the O2, there is no "recommended setting for headphones list" for which headphones for which gain setting.
 
For my headphones in the 32-Ohm to 80-Ohm range, I leave the gain set to low
For my 250-Ohm and 600-Ohm headphones I leave the gain set to high
The 80-Ohm DT770s, will work fine with either setting.
62-Ohm AKG 7XX series (which i do not own) like a lot of juice, so using the high gain setting might be better for them
It might be a little better to just leave the O2 set to the low gain setting, unless you get hard to drive (or high Ohm) headphones.