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O2 AMP + ODAC - Page 93

post #1381 of 5263
Quote:
Originally Posted by adamlr View Post

wow. urm, alright. considering all you have written, including the spoiler, i would consider an upgrade like this: noticeably audibly "more transparent" than the objective set and still being able to drive 95% of all headphones just like the O2. excluding build quality, looks, features, exotic\prestigious components. just soundwise, presenting a flat, linear response and having enough power to drive allmost all headphones, but doing so better than the O2.

in all honesty, i wasnt really considering getting any other amp anyway. but could it be that getting another amp (for the same purpose as the O2, i.e - not more portable or whatever) would simply be redundant? looks like i made the right choice of amps... somehow i still dont buy it though. maybe im too brainwashed confused_face.gif

 

Personally, and it is just my opinion based on my reading of what's out there, I would stockpile different headphones rather than different amps, if I wanted something new (though some amps make no attempt at transparency and so on, definitely sound different, etc.).

 

Also, a very important point to make is that many many amps and DACs, not just the O2 and ODAC—and for many situations and headphones, plenty of options cheaper than the two as well—have pretty excellent measurements in the areas that people test and ostensibly care about, that matter.  O2 and ODAC aren't particularly special, just two more specimens that do a pretty decent job.  Take that as you will.

 

 

 


Quote:

Originally Posted by JakeJack_2008 View Post
 

[...saving space]

long, so I'll put the quote in spoiler (Click to show)

I'd like to buy a new pair of preferably open back headphones: $190 - $299 and use them (only) with the ODAC and O2.

As I mentioned in this thread (and in the ODAC thread) I am using my DT 880 (250 Ohm; 2005 Edition) or  sometimes my Sennheiser HD 595 with the JDS Labs ODAC and O2 as two standalone units.

I am super happy. No complaints. .....but I would like to explore more.

 

I thought about buying the UHA-6S MKII, or iBasso D12, or the Dragonfly, or the latest Merridian Explorer, or the DacPort LX, etc.

but after reading all those discussions in this thread and in the relevant threads about the ODAC, UHA-6S MKII,    ,... DacPort LX, etc

I came to the conclusion that I do not need another dac or amp since the ODAC and O2 are excellent.

Furthermore since  headphones have the biggest impact on the sound  therefore I should focus on buying a better than the DT 880 pair of headphones instead of buying another DAC and headpnone amp. (At least for now.)

I'd like to buy something like AKG K701/702 or Q701, AT ATH-AD900X, Sony MA-900, also closed back AKG K 550, etc.

 

My music: rock/hard rock, mainstream metal and obviously some pop.

I do not  listen to rap/hip-hop, electronic, extreme metal, etc.

(For classical music I can use my Sennhesier HD 595.)

I am not aiming at headphones that, say, reproduce female vocals better than my DT 880s and  I don't care about this at all.

Also, I do not need bass-heavy headphones. Obviously some bass is needed for rock/metal.

 

I know that at least three factors are important in matching a headphone amp with a pair of headphones:

- impedance

- max input power

sensitivity

 

I would prefer higher impedance headphones because of the channel imbalance at low volume levels of the O2. (I haven't tested my O2 for the channel imbalance yet.)

 

 

Recently, I read on this site that the sensitivity factor is more important for

higher-impedance-headphones than the impedance itself.

 

Since this is the thread about ODAC & O2 - although there many  philosophical discussions going on here - this is the best place to ask for an advice regarding matching the O2 with very good headphones (under $300) with the proper impedancemax input power and  above all sensitivity.

 

Thanx in advance.

 

 

Based on the output power, the noise, distortion, and so on... Almost everything should be okay.  O2 should handle most headphones in a similar manner.  Electrostatics: no.  K1000: no.  HE-6 and maybe some vintage K240 and some others: no if you listen loudly.

 

Many people will tell you otherwise, or say they don't like certain pairings (as for the reasons, they vary).  That's fine.  They're just talking about what they perceive when listening for themselves, for what that's worth.  Is there some phenomenon that people haven't discovered yet, that the O2 lacks or does differently than something else?  Or a different way to test things?  I think not; other people think it's out there.

 

Rather than have channel imbalance, you can turn down the volume in software if you're looking at really sensitive IEMs.  For fullsize headphones, O2 channel balance should mostly be in the "okay" or better range (yes, you can do better).  Typical 1 dB off at -55 dB, increasingly better at the higher rotations.  Many headphones are matched worse than that.  Anyway, it doesn't look like you're looking at sensitive IEMs.

 

This is more a question about headphones than amps or anything else, so maybe a different forum is more appropriate.


Edited by mikeaj - 5/5/13 at 7:07pm
post #1382 of 5263
Quote:

Originally Posted by RustA View Post
 

O2 and ODAC are definitely not the last word... Don't believe it. O2 is brilliant on unity gain as it is completely dead silent and offers great soundstage for the price. But it doesn't work great with high impedance headphones, at least from my experience. ODAC is no less great for the price but even my StageDAC has more detail... And if I take its crossfeed and all the different filters in consideration, Meier's DAC is in another league \(or even several leagues above) in terms of transparency.

 

Are the ODAC and O2 the last word? No, but they're audible neutral and thus price, small or large, is immaterial. Some or many or most listeners find other products more pleasing to the ear; but an added filter, including crossfeed, is either inaudible or it makes the product non-neutral.

 

Personally, I'm not interested in filters, but that's nothing more than my preference. Others obviously have different preferences which are no less valid than mine.

post #1383 of 5263

thanks everyone for your detailed replies. this thread is always educational =]

post #1384 of 5263
I have been lurking the thread and it has been great. Learned a lot and got the ODAC on loan.
Looking forward to hearing and seeing the difference.
post #1385 of 5263
Quote:
Originally Posted by RustA View Post

 

O2 and ODAC are definitely not the last word... Don't believe it. O2 is brilliant on unity gain as it is completely dead silent and offers great soundstage for the price. But it doesn't work great with high impedance headphones, at least from my experience. ODAC is no less great for the price but even my StageDAC has more detail... And if I take its crossfeed and all the different filters in consideration, Meier's DAC is in another league \(or even several leagues above) in terms of transparency.

 

Don't get me wrong, I love this Objective stuff and have owned them several times, even had more units at the same time...

Can you share which high impedance headphones it "didn't work great with"? I am curious to know their impedance and power requirements.

post #1386 of 5263

I really don't get the soundstaging comparisons between amps. Staging, as has been mentioned, is all about the positioning of loudspeakers to the listener. The rest is up to the recording.

 

I've sat in about a dozen different cars with aftermarket and OEM stereos, and swapped amps in my own car several times. About the only things that ever matter in the amps are power and distortion. The former should err on 'too much', the latter on 'too little'. Where staging was good in a car it was usually a combination of speaker placement and dedicated electronics like time alignment. In my own car I 'pull' my center stage slightly to the left, but treat myself as if I am not centered in front of the stage. Even with that, some recordings are feeding stuff so much into the left or right channels only that the 'illusion' is destroyed.

 

Headphone staging, to me, is something that can only be done best with electronics and good recordings. Amps just aren't, not matter what people say, a major determining factor of sound reproduction.

post #1387 of 5263
Quote:
Originally Posted by MrMateoHead View Post

. Amps just aren't, not matter what people say, a major determining factor of sound reproduction.

 I disagree. In accordance to your theory the following factors would play no part in sound reproduction?

 

  • Input Sensitivity : The signal level required to obtain full power at the amplifier's output. This is determined by the gain and power rating of the amp. 
  • Total Harmonic Distortion (THD) * : This is a measure of the amount of distortion (modification) of the input signal, which adds additional signal frequencies to the output that are not present in the input signal. THD is commonly measured as a percentage
  • Transient Intermodulation Distortion (TIM) * : Also sometimes called slew induced distortion, this is a form of distortion said to occur when the input signal changes so fast that the output cannot keep up with it. When this happens, feedback ceases to be effective, since the output signal is delayed too long.
  • Frequency Response * : The amount of frequency versus amplitude distortion in an amplifier. A perfect amplifier will amplify all signals equally, regardless of frequency. .
  • Phase Response : This indicates the amount of time that the input signal is delayed before reaching the output, based on the signal frequency.
  • Output Power : This is most commonly measured into a non-inductive resistive load. This is not done to improve the figures or disguise any possible shortcomings, but to ensure that measurements are accurate and repeatable.
  • Output Current # : Not often measured, but sometimes quoted by manufacturers, this represents the maximum current the amplifier can supply into any load.
  • Power Bandwidth : This is usually taken as the maximum frequency at which the amplifier can produce 1/2 of its rated output power
  • Slew Rate # : Closely related to power bandwidth, the slew rate is the maximum rate of change (measured in Volts per microsecond) of the amplifier output. 
  • Output Impedance * : This is the actual output impedance of the amplifier, and has no bearing on the amount of current that can be supplied by the output stage.

 

These all play a part in how our brain perceives factors such as sound stage, bass treble response and etc.


Edited by Fearless1 - 5/6/13 at 8:09am
post #1388 of 5263

emphasis added:

Quote:
Originally Posted by MrMateoHead View Post

Headphone staging, to me, is something that can only be done best with electronics and good recordings. Amps just aren't, not matter what people say, a major determining factor of sound reproduction.

Quote:
Originally Posted by Fearless1 View Post

 I disagree. In accordance to your theory the following factors would play no part in sound reproduction?

 

Come on, now...

 

I don't think you're that much in disagreement.  As for the factors in the list, they're almost all related to power and distortion (which were mentioned): nonlinear and linear.  Though I guess usually people don't lump all that much, including frequency response variations (linear distortion), into the "distortion" umbrella.

 

But anyhow, the majority of amps are pretty good at all of the things in the list.  You can make ones that aren't, but the baseline for comparison is an environment where most do their jobs, with respect to those parameters and more.  I mean, for example how often is slew rate a limiting factor these days, even more so if you're talking typical headphones-level voltages?

post #1389 of 5263

That output impedance one is one of the ones that is very important.....and with the advent of the O2 many vendors are now finally stating what their amps output impedance is and has fixed some to be "better''...or become low enough so this doesnt affect the source in any way.

 

Alex

post #1390 of 5263
Quote:
Originally Posted by adydula View Post

That output impedance one is one of the ones that is very important.....and with the advent of the O2 many vendors are now finally stating what their amps output impedance is and has fixed some to be "better''...or become low enough so this doesnt affect the source in any way.

 

Alex

There has been whole lotta scandal regarding the Meridian Explorer's output impedance which measured about fifty, yes 50  Ohm.

When the Meridian released the Explorer (DAC/amp) they were hiding the output impedance of their Explorer. ...

and you know why,  because it was embarassingly  high.

I think the the first guy who revealed  his measurements was purrin and shortly after Tyll from the InnerFidelity did confirm that

the Explorer's output impedance was about 50 Ohm (48.7?). After this '50 Ohm-revelation' the Meridian, in the next batch/version, 

considerably lowered the output impedance.

All those who had bought their 50 Ohm-Explorers earlier demanded a newer version with much lower impedance.

To find more go to the thread about the Meridian Explorer.

 

The bottom line is: scandal & shame!

 

EDIT

Here's the relevant threads:

http://www.head-fi.org/t/652910/meridian-explorer-dac-amp-stream-of-consciousness-review-warning-not-good/90

and

http://www.head-fi.org/t/650680/news-meridian-releases-the-explorer-pocket-sized-usb-dac

 

The output impedance  of the current model of the Explorer is (about) 5 Ohm.


Edited by JakeJack_2008 - 5/6/13 at 5:48pm
post #1391 of 5263
Quote:
Originally Posted by Fearless1 View Post

Quote:
Originally Posted by MrMateoHead View Post

. Amps just aren't, not matter what people say, a major determining factor of sound reproduction.

 I disagree. In accordance to your theory the following factors would play no part in sound reproduction?

 

  • Input Sensitivity : The signal level required to obtain full power at the amplifier's output. This is determined by the gain and power rating of the amp. 
  • Total Harmonic Distortion (THD) * : This is a measure of the amount of distortion (modification) of the input signal, which adds additional signal frequencies to the output that are not present in the input signal. THD is commonly measured as a percentage
  • Transient Intermodulation Distortion (TIM) * : Also sometimes called slew induced distortion, this is a form of distortion said to occur when the input signal changes so fast that the output cannot keep up with it. When this happens, feedback ceases to be effective, since the output signal is delayed too long.
  • Frequency Response * : The amount of frequency versus amplitude distortion in an amplifier. A perfect amplifier will amplify all signals equally, regardless of frequency. .
  • Phase Response : This indicates the amount of time that the input signal is delayed before reaching the output, based on the signal frequency.
  • Output Power : This is most commonly measured into a non-inductive resistive load. This is not done to improve the figures or disguise any possible shortcomings, but to ensure that measurements are accurate and repeatable.
  • Output Current # : Not often measured, but sometimes quoted by manufacturers, this represents the maximum current the amplifier can supply into any load.
  • Power Bandwidth : This is usually taken as the maximum frequency at which the amplifier can produce 1/2 of its rated output power
  • Slew Rate # : Closely related to power bandwidth, the slew rate is the maximum rate of change (measured in Volts per microsecond) of the amplifier output. 
  • Output Impedance * : This is the actual output impedance of the amplifier, and has no bearing on the amount of current that can be supplied by the output stage.

 

These all play a part in how our brain perceives factors such as sound stage, bass treble response and etc.

 

Would you elaborate on how each of these affects sound stage, bass treble response and etc.? Thanks.

post #1392 of 5263
Quote:
Originally Posted by JakeJack_2008 View Post

There has been whole lotta scandal regarding the Meridian Explorer's output impedance which measured about fifty, yes 50  Ohm.

When the Meridian released the Explorer (DAC/amp) they were hiding the output impedance of their Explorer. ...

and you know why,  because it was embarassingly  high.

I think the the first guy who revealed  his measurements was purrin and shortly after Tyll from the InnerFidelity did confirm that

the Explorer's output impedance was about 50 Ohm (48.7?). After this '50 Ohm-revelation' the Meridian, in the next batch/version, 

considerably lowered the output impedance.

All those who had bought their 50 Ohm-Explorers earlier demanded a newer version with much lower impedance.

To find more go to the thread about the Meridian Explorer.

 

The bottom line is: scandal & shame!

 

EDIT

Here's the relevant threads:

http://www.head-fi.org/t/652910/meridian-explorer-dac-amp-stream-of-consciousness-review-warning-not-good/90

and

http://www.head-fi.org/t/650680/news-meridian-releases-the-explorer-pocket-sized-usb-dac

 

The output impedance  of the current model of the Explorer is (about) 5 Ohm.

Sounds to me like a 'design by ear' product gone terribly wrong

post #1393 of 5263

Hi

 

I've got an ODAC+O2 and need some advice. The gains are 2.5x low and 5x high. I'm looking at buying the Beyerdynamic DT880 to add to my HD650's and K701's. At low gain does anyone have any experience of this set up with the 600 ohm version? Low gain should give 5V output. The 250 ohm looks fine for the low gain setting. Does anybody have any experience of how the 250 ohm sounds relative to the 600 ohm version with this set up?

 

I've also got a technical query. Does this combination of ODAC+O2 work at the higher gain setting or is this higher gain solely for low voltage line level sources? I read on NwAvGuy's blog about overloading input stages and was left confused. The high gain multiplied by the ODAC's output of 2V gives a notional 10V which is greater than the max 7V output of the amp. Does this mean the amp will simply distort when the volume pot asks for more than the 7V available as it runs out of power. Or more worryingly does this mean the input stage is always overloaded at any volume setting so the 5x gain (and any gain over 3.5x for that matter) is unusable with the ODAC supplying it?

 

I'm leaning towards getting the 250 ohm version as I will never have to worry about accessing a voltage over 5V which might be an issue with the 600 ohm version.

 

Thanks in advance

 

Mag

post #1394 of 5263

Hi guys, a quick question by a total newbie: I just got an O2/ODAC combo and I'll use it with my HD598 (I'll switch to HD600 in the future). To use the amp/DAC I have to set something in my PC, like drivers or some audio settings? I'm on Windows 7 x64, my player is Foobar2k, the O2/ODAC is the one from Epiphany.

 

Thanks.

post #1395 of 5263
Quote:
Originally Posted by MagR View Post

Hi

 

I've got an ODAC+O2 and need some advice. The gains are 2.5x low and 5x high. I'm looking at buying the Beyerdynamic DT880 to add to my HD650's and K701's. At low gain does anyone have any experience of this set up with the 600 ohm version? Low gain should give 5V output. The 250 ohm looks fine for the low gain setting. Does anybody have any experience of how the 250 ohm sounds relative to the 600 ohm version with this set up?

 

I've also got a technical query. Does this combination of ODAC+O2 work at the higher gain setting or is this higher gain solely for low voltage line level sources? I read on NwAvGuy's blog about overloading input stages and was left confused. The high gain multiplied by the ODAC's output of 2V gives a notional 10V which is greater than the max 7V output of the amp. Does this mean the amp will simply distort when the volume pot asks for more than the 7V available as it runs out of power. Or more worryingly does this mean the input stage is always overloaded at any volume setting so the 5x gain (and any gain over 3.5x for that matter) is unusable with the ODAC supplying it?

 

I'm leaning towards getting the 250 ohm version as I will never have to worry about accessing a voltage over 5V which might be an issue with the 600 ohm version.

 

Thanks in advance

 

Mag

I am using:

 

laptop ---> ODAC ---> O2 ---> Beyerdynamic DT  880 (250 Ohm; 2005 Edition)

 

The sound is superb. tongue_smile.gif  Although, I believe that purists would find some something here and something there, etc.

 

I've never heard the DT 880 600 Ohm.

 

 

 

 

By the way, there's a very interesting  guide to  Sonic Differences Between DT770-DT990 Models with various impedances: 32 ohm, 250 Ohm and 600 Ohm.

[GUIDE] Sonic Differences Between DT770-DT990 Models & More

http://www.head-fi.org/t/513393/guide-sonic-differences-between-dt770-dt990-models-more


Edited by JakeJack_2008 - 5/7/13 at 9:20am
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