or Connect
Head-Fi.org › Forums › Equipment Forums › Headphone Amps (full-size) › O2 AMP + ODAC
New Posts  All Forums:Forum Nav:

O2 AMP + ODAC - Page 200

post #2986 of 5248
Is anyone using the O2 with HD800 as their main amp?
post #2987 of 5248
I alternate between the O2 and hdvd800. They sound identical but I use the latter more because it has 2 amps inside so I can run the 800s and 600s simultaneously and swap to suit the album. I often go back to the O2 just to keep things in perspective when I see new gear!
post #2988 of 5248
Thanks!
I was worried because i read here somewhere that the HD800 has no bass with 02 , because it's not powerful enough.
post #2989 of 5248
It's plenty powerful enough. Normal listening I have the pot set to about 10-11 o'clock and occasionally 12 with quiet recordings.
post #2990 of 5248
Quote:
Originally Posted by Xenophon View Post
 

Tube amps are great at voltage and hence at higher impedance loads.  For optimal theoretical damping with dynamic headphones you'd need a 7-8 factor difference between the output of the amp and the cans' nominal impedance (which might be < 50% of max impedance at certain frequencies), if it's much less then you  get a typical 'loose' bass due to lack of control over the diaphragm.  Planars are reasonably insensitive to this phenomenon though.  My 38 ohm HE-500 plays very nice with tube amps.

 

 

Majority of headphones are insensitive to that. I don't hear absolutely any difference between a <1 ohm output impedance 1000 dollar headphone amp and a 400 dollar integrated amplifier headphone output with 220 ohms output impedance when it comes to bass tightness, not even with 32 ohm headphones. Only with in-ears there's an audible difference.  People think too much of the damping factor, nobody even cared about it or talked about it before the whole O2 story started blowing it out of proportion and everyone suddenly started talking about it as if it's the most important spec when it comes to headphone amplifiers, and as if only amps with very low output impedance sound good.

post #2991 of 5248

Output Impedance is a very important and a critical part of a good headphone amps design....

 

Many headphones are designed to be used best with near zero output impedance.

 

There is a lot of data published by vendors and the designer of the O2 as well about this topic and damping etc.

 

I would much rather have an amp the has a near zero output impedance period.

 

Things that can go bad with high output impedance is voltage swings to the headphones. As headphone impedance changes with frequency these variations can be very noticeable and huge and thus very audible. 

 

But to some depending on the headphone and source material could possibly like this "sound".

 

If someone wants more technical details send me a PM.

Also: http://www.head-fi.org/t/583798/low-output-impedence-headphone-amps

 

The great thing about the O2 is its near zero output impedance in a low cost headphone amp.

 

Also the new 'ODA" takes all this in account and even offers a selectable damping selection if desired. This way you can play with this specification to see for yourself etc...

 

There are headphones that have designed for higher output impedances than zero...The AKG 550's according to AKG were designed best to be used with a output impedance of 32 ohms +/- 20 ohms. So there are exceptions etc.

 

All the best

Alex


Edited by adydula - 5/30/14 at 6:12am
post #2992 of 5248
Quote:
Originally Posted by adydula View Post
 

Output Impedance is a very important and a critical part of a good headphone amps design....

 

Many headphones are designed to be used best with near zero output impedance.

 

There is a lot of data published by vendors and the designer of the O2 as well about this topic and damping etc.

 

I would much rather have an amp the has a near zero output impedance period.

 

Things that can go bad with high output impedance is voltage swings to the headphones. As headphone impedance changes with frequency these variations can be very noticeable and huge and thus very audible. 

 

But to some depending on the headphone and source material could possibly like this "sound".

 

If someone wants more technical details send me a PM.

Also: http://www.head-fi.org/t/583798/low-output-impedence-headphone-amps

 

The great thing about the O2 is its near zero output impedance in a low cost headphone amp.

 

Also the new 'ODA" takes all this in account and even offers a selectable damping selection if desired. This way you can play with this specification to see for yourself etc...

 

There are headphones that have designed for higher output impedances than zero...The AKG 550's according to AKG were designed best to be used with a output impedance of 32 ohms +/- 20 ohms. So there are exceptions etc.

 

All the best

Alex

 

 

 

Majority of headphones were designed like that K550.   I guarantee you if you sent emails to each and every manufacturer out there to give you a recommendation on output impedance that's perfect for their headphone models, maybe 2 out of 10 would say close to zero ohms. In my experience only a few headphones (mostly in-ears and small portables with 16 ohms of impedance) were affected and showed any difference in sound when comparing them with low and high output impedance amps. Almost no Beyerdynamics or Sennheisers, and most AKG's definitely don't need low output impedance, and most are tuned to work with higher value, Beyer even makes their own amps with high output impedance, so does Sennheiser, not because they don't know how to make ones with low output impedance, which is really simple, but because they tune their headphones and amps to match together as good as possible and to sound as good as possible. Also to match as much equipment out there as possible, and believe it or not, most people don't use separate headphone amps at all, not even with higher end headphones, they just plug them into their integrated amplifiers in their main hi-fi systems, which all have high output impedance.  None of the professional studio equipment has low output impedance either, even really expensive consoles, interfaces, etc. have over 50 ohms of output impedance.

 

Yes, with low impedance headphones low impedance output it is better in theory, but doesn't mean it is always better in practice, some headphones can sound better with some of that "loose" bass added, but it ultimately comes down to personal preference. But it's just wrong to imply that headphone amps with low output impedance are better than those with high output impedance, or that they will sound better, are better engineered, etc. Because it's simply not true, there are many factors other than output impedance alone that matter far more. I mean, my Musical Fidelity M1HPAP is better than Beyerdynamic A1 on paper, it has less than 1 ohm output impedance vs. 120 on the A1, yet, the T1's definitely sound better on the A1, so does the DT990, DT880 and even an 80 ohm DT770.

post #2993 of 5248

Understand what your stating and agree on most of it.

 

I still would like to have an amp that has close to zero output impedance and start from there. Yes there are headphones that will sound "better" at higher output impedances and these can be accommodated with resistors etc, switches etc.

 

All you really need to know is most headphones work best when the output impedance is less than 1/8th the headphone impedance. If you want to be assured a source will work well with just about any headphone, simply make sure the output impedance is under 2 ohms.

 

What is fact is an amp with a very low output impedance impacts the sound in the least manner.

 

If a headphone is designed to work best with a high output impedance amp there usually us a reason for that...

 

there are 3 areas that output impedance matters:

 

1. The greater the output impedance the greater the voltage drop with lower impedance loads. This drop can be large to enough to prevent driving low impedance headphones to sufficiently loud levels.

 

2. Headphone impedance changes with frequency. If the output impedance is much above zero this means the voltage delivered to the headphones will also change with frequency. The greater the output impedance, the greater the frequency response deviations. Different headphones will interact in different, and typically unpredictable, ways with the source. Sometimes these variations can be large and plainly audible.

 

3. As output impedance increases electrical damping is reduced. The bass performance of the headphones, as designed by the manufacture, may be audibly compromised if there’s insufficient damping. The bass might become more “boomy” and less controlled. The transient response becomes worse and the deep bass performance is compromised (the headphones will roll off sooner at low frequencies). A few, such as those who like a very warm “tube like” sound, might enjoy this sort of under damped bass. But it’s almost always less accurate compared to using a low impedance source.

 

The 1/8 rule comes into play here to mitigate the "possible" issues in these areas.

 

If you pick a high dollar amp made by a firm that makes headphones it may be that that amp may very well work better with those cans, but may not work well with others.....

 

Even the designer of the O2 states some headphones will sound better with a higher output impedance.

 

Back in the old days stereo receivers and professional gear had high output impedance jacks for sure.There is a lot of history here and the 120 ohm 1996 standard that Stereophile scoffed at....

 

But even Sennheiser has stated they design their audiophile and portable headphones for zero ohm sources.

 

With all this rambling output impedance is still very important thing to consider and damping etc...several amps since the advent of the O2 have started to spec this out clearly so consumers are aware. This IMO is a good thing.

 

Alex

post #2994 of 5248

Here is a post from another Headfi person sometime back...

 

"

It's largely a matter of perspective:  If certain headphones don't pair well with a neutral, low output impedance amp, I think xxxGuy would point out that it's not the amp's fault.  I would agree here, since designing around such an amp is really the only way to get a stable reference point for headphone performance:  The concept of amp neutrality is objectively well-defined, but coloration spans a huge multidimensional spectrum.  Similarly, 0 ohm output impedance is well-defined, whereas banking on pretty much any other output impedance is totally arbitrary.  For the sake of standardization and keeping consumers from going crazy and broke, headphone designers should really be designing around 0 ohm output impedance amps.  If certain headphones are depending on a high output impedance amp to roll off certain frequencies that the headphones go overboard on, I'd personally consider that a design flaw in the headphones.

 

In a perfect world, all headphones would be designed around neutral, low output impedance amps, but this is the real world...and sometimes maybe they aren't.  Even if they are, headphones are impossible to make perfect with our current technology, so even some headphones technically designed around low output impedance amps might have flaws that some higher output impedance amps could alleviate by happenstance.  (Or maybe you just prefer muddy bass? wink.gif)  At that point, you pretty much have to search for a Goldilocks zone...but what if a particular amp DOES compensate perfectly for a headphone's flaws?  In that case, the amp and headphone combination becomes much more than the sum of its parts.  Independently, I'd consider both flawed...but together, they could be a perfectly viable or formidable choice for great audio.

 

Ultimately, no amp will be the best choice for all headphones.  However, I think a powerful, objectively well-measuring, neutral, low output impedance amp is inherently more versatile than colored amps:  It may not compensate for any sonic flaws in the headphones, but it also won't introduce any of its own that will exacerbate them or otherwise make things worse.  Neutral amps may not sound great with ALL headphones, and saying they do would be an overstatement...but they're a good middle ground between warm and bright, and they're really the only stationary targets for designing headphones around.  The same applies to low output impedance, since the effect of high output impedance is an arbitrary sort of frequency response rolloff, which would count as a source of coloration.

 

That's a big reason why I went for the O2:  I'll just restrict my headphone purchases to the ones that work well with it, which means "no stats, K1000's, Sextets, or headphones that need extra coloration to sound good."  The last part means I'm sacrificing a few opportunities in favor of simplicity:  No headphones are perfect, and there may be a particular amp that matches a particular pair of headphones better than the O2 will ever match anything.  For instance, the FA-002W High Editions can be really great headphones according to LFF, but they're picky about amps, and the O2 (and presumably any other neutral amp) doesn't make the cut.  Nevertheless, I want the versatility to try (and judge) a bunch of cans without worrying about amp coloration as a variable or trying n*m combinations of headphones and amps, so the O2 is perfect for me.  I'd recommend it (or another inexpensive and neutral amp, such as The Wire) to anyone in the same boat.  If I need to tweak, I'll go for an EQ or DSP.  (It is interesting though that you could add a switched output resistor to it.  That would definitely increase the versatility aspect further.)

 

However, if you're set on a particular flagship headphone, you may get more mileage finding the perfect amp for that particular headphone model.  If you're a serious headphone hobbyist (deep pockets wink.gif), you may get more mileage just playing with amp options too.

 

Here is the link to this discussion: http://www.head-fi.org/t/583798/low-output-impedence-headphone-amps/15

 

Enjoy

Alex

post #2995 of 5248

Just for an exercise in getting the truth from the source:

 

Here is a note to Senn Support:

 

Message:
HD800 What is the amplifier output impedance for the best sound from the HD800's? Amps have different output impedances from near zero ohms to several hundred?

Thanks in Advance

Alex

 

Reply, which was very quick:

 

Good Afternoon Mr Alex

Thank you for contacting Sennheiser Technical Support. The HD 800 headphones have an impedance of 300 Ohms which means that they need to be connected to an amplifier that is outputting at least 300 Ohms. Anything less than 300 Ohms and the headphones will not be able to reach their full potential. For the HD 800 we would recommend our HDVD 800 amplifier.

Have a great day.
 

(name removed).

 

Now the HDVD 800 amplifier is only $1995 and its output impedance spec is listed as 16 ohms?

 

Now how is that going to work?

 

Alex


Edited by adydula - 5/30/14 at 1:47pm
post #2996 of 5248
Quote:
Originally Posted by adydula View Post
 

Just for an exercise in getting the truth from the source:

 

Here is a note to Senn Support:

 

Message:
HD800 What is the amplifier output impedance for the best sound from the HD800's? Amps have different output impedances from near zero ohms to several hundred?

Thanks in Advance

Alex

 

Reply, which was very quick:

 

Good Afternoon Mr Alex

Thank you for contacting Sennheiser Technical Support. The HD 800 headphones have an impedance of 300 Ohms which means that they need to be connected to an amplifier that is outputting at least 300 Ohms. Anything less than 300 Ohms and the headphones will not be able to reach their full potential. For the HD 800 we would recommend our HDVD 800 amplifier.

Have a great day.
 

(name removed).

 

Now the HDVD 800 amplifier is only $1995 and its out impedance spec is listed as 16 ohms?

 

Now how is that going to work?

 

Alex

Wonder what that guy was smoking but it sure wasn't a pack of Gauloises....  He's off his rocker about the amp, anyone with eyes can plainly see that those 300R are not exactly constant across the fq spectrum AND iirc the HDVD-800 output Z is about 46 R.......

post #2997 of 5248

:):L3000::beyersmile::blink:

post #2998 of 5248

To be fair I asked Senn about this discrepancy and got this reply:

 

Good Afternoon Mr Dydula,

Thank you for contacting Sennheiser Technical Support. The HDVD 800 is capable of producing a range out output levels going all the way up to 600 Ohms.

Have a great day.

 

FYI

 

Alex
 

post #2999 of 5248
Quote:
Originally Posted by adydula View Post
 

Just for an exercise in getting the truth from the source:

 

Here is a note to Senn Support:

 

Message:
HD800 What is the amplifier output impedance for the best sound from the HD800's? Amps have different output impedances from near zero ohms to several hundred?

Thanks in Advance

Alex

 

Reply, which was very quick:

 

Good Afternoon Mr Alex

Thank you for contacting Sennheiser Technical Support. The HD 800 headphones have an impedance of 300 Ohms which means that they need to be connected to an amplifier that is outputting at least 300 Ohms. Anything less than 300 Ohms and the headphones will not be able to reach their full potential. For the HD 800 we would recommend our HDVD 800 amplifier.

Have a great day.
 

(name removed).

 

Now the HDVD 800 amplifier is only $1995 and its output impedance spec is listed as 16 ohms?

 

Now how is that going to work?

 

Alex

 

I guess that he wanted to say that you need an amplifier that is rated to drive at least a 300 ohms headphone . (wich allready don't mean anyting : / ) .

 

1th level support , are from marketing / secretarial departement? :o


Edited by HaVoC-28 - 5/30/14 at 2:36pm
post #3000 of 5248
That kind of poor communication and engagement is enough to make me want to sell my HD800s!!! If you make the most advanced headphone ever at least have the confidence to be transparent with your information and employ someone to respond with facts rather than random bull**** and lack of understanding !
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: Headphone Amps (full-size)
Head-Fi.org › Forums › Equipment Forums › Headphone Amps (full-size) › O2 AMP + ODAC