[turokrocks]

Quote:

Oliver is building mine with gain set at 2x and 5x - that should be fine for my undemanding can collection. Thanks for the info though - nwavguy has written so much on his blog that it can be hard to keep on top of it all.

Please update us as you receive your O2 as i ordered  one a week ago.

 

[Willakan]

To put the gain settings into perspective, I find my O2 unbearably loud much past 9 o'clock on the volume control. However, rather than IEMs, I am listening with AKG K702s. I built mine with 3.1X gain - I would seriously consider unity gain for IEMs, at least as one of the settings. Source voltage is 2.1V RMS.
 
I do listen quite quietly, but even so...

 

[Head Injury]

Something like 1x and 3x gain would work if you're planning to use this with IEMs. 1x would be enough for most of them with a 2 V desktop DAC, and 3x would be good for DAPs (which are like 0.5-1 V or something right?) 3x would also work with any full-sized headphones in the future and avoids clipping with normal 2ish V sources.

 

[bada bing]

Quote:

To put the gain settings into perspective, I find my O2 unbearably loud much past 9 o'clock on the volume control. However, rather than IEMs, I am listening with AKG K702s. I built mine with 3.1X gain - I would seriously consider unity gain for IEMs, at least as one of the settings. Source voltage is 2.1V RMS.
 
I do listen quite quietly, but even so...

I just built my second O2 board. The first was built with the default gain, my second with 1X and 3x. I listen just about exclusively to HD650 and HD800 at my desk and use a couple ~2v desktop sources. 1x has all the volume I need for the HD650 & HD800, I listen with the knob about 10:00 at 1x gain with HD650. I would consider anything above 3x gain to be usable only for some very difficult & unusual headphones or for use as a pre-amp. Later this week I will break out my K1000's and see if they can make the O2 choke.   
 

 

[LizardKing1]

I'm sorry, but I must ask this: the gain multiple (3X, 4X,...) refers to how much the source's voltage will be amplified, right? So not all DACs output the same? I'm just trying to know so I can tell if my E7's DAC output will be enough coupled with the O2, as soon as I can find out how much the output is which is hard, since almost no one uses it as a DAC only.

 

[Willakan]

I *think* the Fiio's output voltage is about 1.3V RMS, but don't quote me on that. The most any USB power-only DAC is going to pump out is about 1.4V RMS.
 
@bada bing:
 
I think the O2 choking on headphones designed to be driven from a speaker power amp is a foregone conclusion.

 

[khaos974]

Quote:

I'm sorry, but I must ask this: the gain multiple (3X, 4X,...) refers to how much the source's voltage will be amplified, right? So not all DACs output the same? I'm just trying to know so I can tell if my E7's DAC output will be enough coupled with the O2, as soon as I can find out how much the output is which is hard, since almost no one uses it as a DAC only.

DACs voltage outputs vary wildly, the output of a CD player is supposed to be 2 Vrms, but a lot of sources ohave outputs that vary between 1V and 3V especially some more exotic audiophile sources. Portable sources usually don't exceed 1V.
 
 

 

[katzer1]

I got my O2 from another diyaudio builder called aerohoff.
He lives close to me so I got to meet him in person. He is a very nice fellow who does an excellent job yet maintains zero attitude about it.
 
I like this amp a lot: it drives my HD580, ER4P/S and DT880 (600ohm) wonderfully.
It just takes the signal from my DAC (rega dac) and adds a volume knob on top.
The soundstage feels very wide, the separation is excellent and it is neutral, it just amplifies the source signal without any fusses. Good recordings sound good, poor recordings sound poor.
 
 

 

[turokrocks]

Quote:

I got my O2 from another diyaudio builder called aerohoff.
He lives close to me so I got to meet him in person. He is a very nice fellow who does an excellent job yet maintains zero attitude about it.
 
I like this amp a lot: it drives my HD580, ER4P/S and DT880 (600ohm) wonderfully.
It just takes the signal from my DAC (rega dac) and adds a volume knob on top.
The soundstage feels very wide, the separation is excellent and it is neutral, it just amplifies the source signal without any fusses. Good recordings sound good, poor recordings sound poor.
 
 

Thanks for the update, can you be more elaborate ?
 
 

 

[estreeter]

sobbingwallet does a pretty good job of summing it up in the other thread - if your O2 is working properly, you will be hearing your source/the recording and any coloration introduced by your phones. Theoretically, the amp should be invisible - mine hasn't arrived yet, but I believe that is the ideal for a neutral amp.

 

[everlong]

Was thinking of building this, but it need to end up in a nice enclosure, and I would like to build a DIY DAC(USB) too, that ends up in the same enclosure type(not the same box). So both the amp and dac will look like it comes of the same brand.
 
Any ideas on that? And what DIY DAC would be a good match for the amp?

 

[upstateguy]

Quote:

sobbingwallet does a pretty good job of summing it up in the other thread - if your O2 is working properly, you will be hearing your source/the recording and any coloration introduced by your phones. Theoretically, the amp should be invisible - mine hasn't arrived yet, but I believe that is the ideal for a neutral amp.

Hi estreeter
 
Do you have a link for the other thread?
 
 

 

[shadow419]

Quote:

Hi estreeter
 
Do you have a link for the other thread?
 
 

http://www.head-fi.org/t/577535/o2-build-complete-let-the-objective-subjective-listening-tests-commence/165
 
Post #176

 

[estreeter]

Thanks, shadow419 - I have to be careful what I link to given the sensitivity of the subject matter here - there were rules somewhere, but I just err on the side of caution cowardice. 

 

[Yoga Flame]

Quote:

Was thinking of building this, but it need to end up in a nice enclosure, and I would like to build a DIY DAC(USB) too, that ends up in the same enclosure type(not the same box). So both the amp and dac will look like it comes of the same brand.
 
Any ideas on that? And what DIY DAC would be a good match for the amp?

The O2's enclosure is the same type as the recommended one for the AMB gamma1 (config F). The gamma2 also.