O2 AMP + ODAC
Apr 13, 2014 at 4:58 AM Post #2,581 of 5,671
   
 
 
That, and the ear pads. This is purely an anecdote.
The pads of my old headphone is so worn that it fell off. The effect is immediate. You notice the sound being thin and not musical and all that.
New pads. Voila. Good as new.

I thought I could identify the difference between odac and fiio e10 . These two dacs measures well ( odac is better numerically of course, but e10 fits my applications as well) and I am quite confidently say if you do a proper double blind test on me, I would not be able to differentiate the both of them consistently with my current headphone.
The pads on the other hand though, you have to be deaf to not be able to tell if it is working or not.

 
I agree most of the difference that can be improved or become worse is in the headphones. There is only so much improvement that can be done on amp/source. A crappy headphone remains crappy regardless of source. Although a very good sounding headphone can sound bad if not sufficiently amped. I think this can be easily rectified without costing much.
 
Apr 13, 2014 at 5:45 AM Post #2,582 of 5,671
O2 + odac or teac ud h01? Both usd 250
 
Apr 13, 2014 at 7:28 AM Post #2,584 of 5,671
 
i saw their specs page. they seems to be doing THD with -1dbfs... that's not very nice is it?

I'm surmising (but will happily stand corrected if someone has other info) that it has some technical (other than pimping the results) reason. The ODAC's designer also lists his THD+N specs at 20Hz and 10kHz at -1 dBFS.  He/she's btw also mentioning Violectric as one of the few manufacturers who provide meaningful measurement data.  About the USB implementation I quote the following, hoping that this is allowed as a direct link is not according to Head-FI TOS:
 
"There are only a few USB interface chips capable of 24 bit operation. The best option we could find is the Tenor TE7022. It’s used in the Violectric USB 24/96 and several other commercial 24 bit USB DACs. Notably, it does not require proprietary drivers to work with any popular operating system including Windows because, like the Benchmark DAC1, it’s a USB Audio Class 1 interface. It also has respectably low jitter."
 
If James-UK is still interested:  best not to clutter the thread with methodology discussion so feel free to pm me on this.  
 
Apr 13, 2014 at 2:37 PM Post #2,586 of 5,671
thank you for the clarification. I might be double up the investment now just go for nad d3020 as my local store bundle a free pair of psb speaker ....
 
Apr 13, 2014 at 3:19 PM Post #2,587 of 5,671
The one aspect of the sound I am getting from my system, iPhone 5S, O2,HD600 that I would like to improve is "presence". Which component would most affect this?
 
Apr 13, 2014 at 5:45 PM Post #2,589 of 5,671
Is jitter something to be concerned about with present day USB DACs? I have been told that it is a non-issue as far as audio use is concerned.
 
Apr 13, 2014 at 6:28 PM Post #2,590 of 5,671
Is jitter something to be concerned about with present day USB DACs? I have been told that it is a non-issue as far as audio use is concerned.

The way I understand it is that if properly implemented any jitter differences between modern DACs should be below the threshold of audibility, the gains that ultra-precision DACs bring are mathematical, not audible.  But I guess this is one of those contentious topics that makes DACs such as the Calyx femto sell (no negative reflection on the Calyx btw, it looks built like a very high end tool and has many other features, it's just that I doubt femtosecond precision makes a difference).  
 
Apr 14, 2014 at 9:28 AM Post #2,591 of 5,671
  I'm surmising (but will happily stand corrected if someone has other info) that it has some technical (other than pimping the results) reason. The ODAC's designer also lists his THD+N specs at 20Hz and 10kHz at -1 dBFS.  He/she's btw also mentioning Violectric as one of the few manufacturers who provide meaningful measurement data.  About the USB implementation I quote the following, hoping that this is allowed as a direct link is not according to Head-FI TOS:
 
"There are only a few USB interface chips capable of 24 bit operation. The best option we could find is the Tenor TE7022. It’s used in the Violectric USB 24/96 and several other commercial 24 bit USB DACs. Notably, it does not require proprietary drivers to work with any popular operating system including Windows because, like the Benchmark DAC1, it’s a USB Audio Class 1 interface. It also has respectably low jitter."
 
If James-UK is still interested:  best not to clutter the thread with methodology discussion so feel free to pm me on this.  


I am also curious about the reason behind using different input for different Hz test signal.
odac guy used 0 dbfs for 100hz but -1 for 20 and 10k. Is there a reason for such difference?


In a certain blog post about a crap dac, a certain guy who must not be named used -1 dbfs test signal which gave better results than 0 dbfs , since at 0 dbfs there is a power supply issue with that dac and the distortion is massive.
Would it be the same case here?
 
Apr 14, 2014 at 2:43 PM Post #2,592 of 5,671
I'd like to upgrade my USB cable. Not for sound (not possible) but something better built and a bit swisher looking would be nice. What's the purpose of the ferrite bead (?)? I've never seen one on after-market cables so does it matter?
 
Apr 14, 2014 at 3:59 PM Post #2,593 of 5,671
Does anyone have any recommendations on gain settings (1x I expect?) for O2 when paired with some Sennheiser momentums? (18ohm, 110db/v, 200mw max)

I'd like to upgrade my USB cable. Not for sound (not possible) but something better built and a bit swisher looking would be nice. What's the purpose of the ferrite bead (?)? I've never seen one on after-market cables so does it matter?


The purpose of the ferrite bead is to prevent RF picked up in the cable shield flowing, often referred to as a choke. PC often a good source of electrical noise and RF emissions, so there to stop any currents induced on the shield reaching the DAC.

If you just want something pretty there is a UK site, think it's called pexon or something like that which is popular with keyboard moderns as they make custom USB cables with para cord sleeves if looks are important. Think he does short audio cables as well made to order but disclaimer never used them and not affiliated in any way! Digital USB is USB, probably be just as ok as original cable, something from maplin or something out of china for few quid from farnell or somewhere!

Found this thread quite informative, can see there is a lot of passion on this forum and not just for music :wink: I just want something half decent for PC to replace digital out to amp and speakers I no longer have space for since downsizing home office so o2&odac seem ideal.
 
Apr 14, 2014 at 4:52 PM Post #2,594 of 5,671
Thanks for the USB info. I can help you too. I own the O2 with gains of 1x / 3x. It drives every set of phones I own on 1x. From the insensitive Q701 to the 300Ohm HD650. Any genre you like. I don't even know for a fact that 3x gain works, lol. It will drive your Momentums no sweat.
 
Apr 14, 2014 at 8:09 PM Post #2,595 of 5,671
I read here somewhere that the SQ of the O2/ODAC depends on the quality of the USB you are using.
What does that mean? aren't all USB sockets the same quality? and how can you tell if your laptop's USB is any good?
Thanx.
 

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