[Bill-P]

  From level matched listening tests using the HE-560 driven by the O2+ODAC and higher wattage Hifiman EF5, I'm not getting any distortion from the O2.  If anything, the  EF5, being a tube hybrid, subtly smears the detail more due to the tube input stage.  This is on tracks that I know well and what details to listen for. 

I was impressed with the detail level on the EF5 already, but the O2 is just cleaner. The gain on the O2 should be matched with the input voltage, of course, and the EF5 has more headroom on the volume knob. 

Since you mention it, I also switch between to a STAX electrostat from time to time, and as far as this 'inaudible distortions that smears the micro details' are concerned, it really seems you like to cherry pick your arguments, providing technically plausible but one-sided explanations that have no basis in actual usage an experience. 

I'd personally put much more weight on extended listening experiences of people who actually have the equipment on hand, over your soap box musings. 

 
Where did you get that the Hifiman EF5 is higher wattage?
 
It uses an OPA275 op amp for its output stage, as far as I know... (unless Hifiman doesn't know their specifications well), the datasheet recommends that the OPA275 be current-limited to 30mA (peak to peak) swing. Even when the designer decides not to do that limitation, the op-amp itself has an internal 30-Ohm resistor that limits its current swing to +40mA and -90mA, so if anything that's actually worse current specs than the O2's theoretical +200mA and -200mA.
 
Here is the datasheet in question:
http://www.analog.com/static/imported-files/data_sheets/OP275.pdf
 
So in fact, you just supported my argument that when you have less headroom, distortion would smear details way before the brick wall is reached.
 
But please feel free to correct me if you find anything else.

 

[mandrake50]

   
 
 
 
Because most headphones (non-planar) actually have varied impedance and varied distortion figures depending on frequencies as well. It's absolutely impossible to list such a thing and have it applied universally across all headphones, or even to a very specific headphone. In fact, it would make almost no sense at all.
 
Or in other words: a headphone that is rated at 100 Ohm impedance may have an impedance of 250 Ohm at bass frequencies. It's not linear. Planar magnetic headphones like the HE-560 are close to being linear, but in practice, they still have some variation... even if not due to the headphone itself, it's due to the cable.
 
Manufacturers would need to list a whole table of values in that case, but then how many people would actually look at these tables, right?
 
So the specs of the amp would be there only as a ballpark figure, and then the user will have to do the rest of the calculations for his or her specific headphone. But as I explained above, even the method of measuring the headphone is not standardized, so one would have to dig pretty deep down the rabbit hole in order to understand anything meaningful out of this. And that's why measurements for headphones typically are there as an estimate rather than an actual depiction of how the headphone actually sounds like.
 
Fastest way to know is still to plug the headphone into the amp and listen, I'd say.
 
 
Well, like I said, they'd need to publish a whole table for it to be truly "clear", which is pretty excessive, and not a lot of people would take that as being anything meaningful, since... if one is a consumer, one would only care about short and concise lists, and if one is a technician or engineer who understands a thing or two, then it'd be faster to measure the headphone and amp directly rather than referencing such an insane table.
 
As for something with only 10W of power but it's listed (in an ad) as 200W, I'd agree... that some crazy marketing is involved.
 
But honestly, the problem is... in an age where everyone else is quoting 4-6-10W of "power", I don't think a company would want to quote 1W of power. A tech-head or engineer would see that and pay it no mind, but a consumer would go: "not enough power" and skip the product. In a sense, it's not like Schiit or other amp makers are selling these amps exclusively to tech-heads and engineers.

 

 

My point was, if they can quote power output at specific impedances, they could quote the rest of the specs, even if only for those specific impedances. No reason to carry it to the extremes of logic! One can always get carried away, as it is the Headfi tradition, in logical absurdities, but it is not required for additional clarity in published specifications.
 
I agree with the "just listen" concept, however it is impractical for many to do that. Of course, power output, as discussed so much here, is just part of the equation. Maybe a small one, but many tell people to give it up if the amp does not meet minimum power requirements. Knowing that going in would possibly eliminate lots of the trial and error part of the selection process.
 
This is disturbing:
"But honestly, the problem is... in an age where everyone else is quoting 4-6-10W of "power", I don't think a company would want to quote 1W of power. A tech-head or engineer would see that and pay it no mind, but a consumer would go: "not enough power" and skip the product. In a sense, it's not like Schiit or other amp makers are selling these amps exclusively to tech-heads and engineers."
 
So the marketing aspects are more important than accurately reporting the facts. More than likely it is absolutely true, but that reality sucks!!
 
Yes "Caveat Emptor", but that is how the receiver and power amp (cheap) guys got regulated years ago. It would be nice to have uniformity and transparency  in reporting specifications! Notwithstanding marketing pressures!

 

[Bill-P]

  My point was, if they can quote power output at specific impedances, they could quote the rest of the specs, even if only for those specific impedances. No reason to carry it to the extremes of logic! One can always get carried away, as it is the Headfi tradition, in logical absurdities, but it is not required for additional clarity in published specifications.
 
I agree with the "just listen" concept, however it is impractical for many to do that. Of course, power output, as discussed so much here, is just part of the equation. Maybe a small one, but many tell people to give it up if the amp does not meet minimum power requirements. Knowing that going in would possibly eliminate lots of the trial and error part of the selection process.
 
This is disturbing:
"But honestly, the problem is... in an age where everyone else is quoting 4-6-10W of "power", I don't think a company would want to quote 1W of power. A tech-head or engineer would see that and pay it no mind, but a consumer would go: "not enough power" and skip the product. In a sense, it's not like Schiit or other amp makers are selling these amps exclusively to tech-heads and engineers."
 
So the marketing aspects are more important than accurately reporting the facts. More than likely it is absolutely true, but that reality sucks!!
 
Yes "Caveat Emptor", but that is how the receiver and power amp (cheap) guys got regulated years ago. It would be nice to have uniformity and transparency  in reporting specifications! Notwithstanding marketing pressures!

 
Well, I guess I should make it clear. Output at one specific impedance won't necessarily reflect the actual capability of the amplifier itself.
 
For instance, at higher impedances, the amp would be voltage-limited, but not current-limited. In fact, current requirement drops with impedance rising, so low impedance would be current-limited but not voltage-limited. They'd then have to quote 2 different impedances at the extremes at the very least to be clear. This is different from the speaker market where impedance is already standardized, so there's no such interaction like this.
 
If it's a planar, then impedance would be fixed all throughout the frequency range, so they'd only need to quote power figure once and it'll apply to the whole range.
 
If it's a dynamic headphone, though, due to their phase shifts that occur at different frequencies, it'll be hard to quote distortion figures, and also equally hard to quote power figures at different frequencies due to shifting impedances. So that's one possible reason they don't want to do it.
 
But yeah, marketing plays into it, too. It's disgusting, but that's how the industry works.
 
If amp makers were absolutely honest about their works, then others who aren't so honest would just exploit that in a power game.
 
Though it is true that more headroom would be good, I'd agree that at some point, it'll just be moot to quote massive power specs. The problem is... even when they reach that point, manufacturers will still have to keep pushing and keep posting some crazy high max specs (or RMS) just to make their products stand out in a market full of sharks.

 

[Mike In Bama]

Just to chime in another thought, I find $20 a month reasonable for this reason. To buy one CD or SACD a month you will near or exceed this price.

No one has access to everything out there to listen to. If something comes recommended to me, I'll give it a listen. That price will save me much more in expensive mistakes in purchases.

Even I ❤ Radio has some merit there. I have discovered many new and interesting artists by intentionally looking outside of the box. Forget SQ for a second. The music is what we are all here for.

Discovering a good unknown-to-me band is a great joy! Hell, I'm old. I'm not on the bleeding edge of what's going on anymore. I don't have the time. Remember 1981 when MTV kicked off? No one had ever heard of the bands on display. We sat mesmerized by seeing the people we heard on the radio but couldn't spot in a police lineup.

This is turning into an LP vs CD p*****g contest!

 

[mandrake50]

   
Well, I guess I should make it clear. Output at one specific impedance won't necessarily reflect the actual capability of the amplifier itself.
 
For instance, at higher impedances, the amp would be voltage-limited, but not current-limited. In fact, current requirement drops with impedance rising, so low impedance would be current-limited but not voltage-limited. They'd then have to quote 2 different impedances at the extremes at the very least to be clear. This is different from the speaker market where impedance is already standardized, so there's no such interaction like this.
 
If it's a planar, then impedance would be fixed all throughout the frequency range, so they'd only need to quote power figure once and it'll apply to the whole range.
 
If it's a dynamic headphone, though, due to their phase shifts that occur at different frequencies, it'll be hard to quote distortion figures, and also equally hard to quote power figures at different frequencies due to shifting impedances. So that's one possible reason they don't want to do it.
 
But yeah, marketing plays into it, too. It's disgusting, but that's how the industry works.
 
If amp makers were absolutely honest about their works, then others who aren't so honest would just exploit that in a power game.
 
Though it is true that more headroom would be good, I'd agree that at some point, it'll just be moot to quote massive power specs. The problem is... even when they reach that point, manufacturers will still have to keep pushing and keep posting some crazy high max specs (or RMS) just to make their products stand out in a market full of sharks.

I agree with everything you said. Still, if there were uniform reporting at set impedances that everyone adhered to, it would be a great starting place for comparison.
It could not reflect absolute performance for every phone across it full operating frequency, true! But as you very well said, that is pretty much impossible. Stating full power specs with frequency used for the measurement and distortion levels at specific loads, could be easily done.
 
The marketing solution is to build a better amp!

 

[Mike In Bama]

mandrake50: The marketing solution is NOT to build a better amp.

The marketing solution is to take advantage of the confusion and make money off of THAT.

The LOGICAL solution is to build a better amp. (IMO, of course)

 

[mandrake50]

mandrake50: The marketing solution is NOT to build a better amp.

The marketing solution is to take advantage of the confusion and make money off of THAT.

The LOGICAL solution is to build a better amp. (IMO, of course)

Precisely ... pretty much what I PMd to BillP. A really "better" amp will sell itself . As long as the real info is recorded, and the rest of the products adhere to the same reporting standards...
Which just is not happening!

 

[money4me247]

The above amplifier discussion is quite interesting. the he-560's sound can noticeably change with different amplifiers from personal experience. However, I have never experienced any audible sonic imperfections/distortions/noise/clipping even using my crappy cheap low-powered Bravo V3. The bass presence was lacking for sure, and the final sound signature was not to my liking. 
 
So I personally think that the power requirement claims and the he-560's difficulty to drive is quite exaggerated. Hifiman specifically stated that they engineered the HE-400i and HE-560 to be easier to drive than their older generation planar magnetic headphones.
 
I think that many people here are looking for a very certain specific sound signature that they enjoy & anything else is unacceptable for them. They will spend a lot of time trying to match amplifiers & feel like the he-560s are not performing optimally for their personal tastes with certain equipment matches. I think that a personal preference is playing a larger role here than the actual amplifier capabilities or performance.
 
You can definitely get great performance from the HE-560s using an inexpensive amplifier. The actual calculated power requirements are about half a watt, so 4+ watts is definitely supreme overkill. Nothing wrong with having that much power, but that much power is definitely not necessary to enjoy these headphones. I think 1-2 watts is more than enough with ample extra juice for 'headroom.'

 

[DarrenLays]

  The above amplifier discussion is quite interesting. the he-560's sound can noticeably change with different amplifiers from personal experience. However, I have never experienced any audible sonic imperfections/distortions/noise/clipping even using my crappy cheap low-powered Bravo V3. The bass presence was lacking for sure, and the final sound signature was not to my liking. 
 
So I personally think that the power requirement claims and the he-560's difficulty to drive is quite exaggerated. Hifiman specifically stated that they engineered the HE-400i and HE-560 to be easier to drive than their older generation planar magnetic headphones.
 
I think that many people here are looking for a very certain specific sound signature that they enjoy & anything else is unacceptable for them. They will spend a lot of time trying to match amplifiers & feel like the he-560s are not performing optimally for their personal tastes with certain equipment matches. I think that a personal preference is playing a larger role here than the actual amplifier capabilities or performance.
 
You can definitely get great performance from the HE-560s using an inexpensive amplifier. The actual calculated power requirements are about half a watt, so 4+ watts is definitely supreme overkill. Nothing wrong with having that much power, but that much power is definitely not necessary to enjoy these headphones. I think 1-2 watts is more than enough with ample extra juice for 'headroom.'

 
I agree.
 
I have a friend that did some research on "hard to drive" rumours, and half of them were SEVERELY over-exaggerated.  He even took into account of peaks etc, still no where near what people recommend.

 

[Ron12]

  The above amplifier discussion is quite interesting. the he-560's sound can noticeably change with different amplifiers from personal experience. However, I have never experienced any audible sonic imperfections/distortions/noise/clipping even using my crappy cheap low-powered Bravo V3. The bass presence was lacking for sure, and the final sound signature was not to my liking. 
 
So I personally think that the power requirement claims and the he-560's difficulty to drive is quite exaggerated. Hifiman specifically stated that they engineered the HE-400i and HE-560 to be easier to drive than their older generation planar magnetic headphones.
 
I think that many people here are looking for a very certain specific sound signature that they enjoy & anything else is unacceptable for them. They will spend a lot of time trying to match amplifiers & feel like the he-560s are not performing optimally for their personal tastes with certain equipment matches. I think that a personal preference is playing a larger role here than the actual amplifier capabilities or performance.
 
You can definitely get great performance from the HE-560s using an inexpensive amplifier. The actual calculated power requirements are about half a watt, so 4+ watts is definitely supreme overkill. Nothing wrong with having that much power, but that much power is definitely not necessary to enjoy these headphones. I think 1-2 watts is more than enough with ample extra juice for 'headroom.'

 
Of course it is exaggerated... I don't even bother to discuss this myself again. I have found in general that with Hifiman headphones (HE-4 and HE-500 in my case), you can get a bit tighter and deeper bass + improved transients using amplifiers capable of powering them in a more optimal way but the difference is small, not night-n-day. You would have to listen to demanding music (like classical) with headphones like HE-6 to spot a difference that would be worth this generic 'you are not powering your headphones optimally, you have no idea what they are capable of' type of discussion that arises from time to time.
 
I can see why someone would want to invest time and resources into finding an optimal amplifier for their headphone but the thing is this is much more about getting the tonal synergy right than freaking out about amps' power specs.

 

[4Real]

Out of curiosity has anyone tried "Replay Music" with Tidal? as I know it now supports FLAC as well as WAV.
 
So, Audio Driver > FLAC/WAV
 
I used it with Spotify to get music onto my portable rig, set up correctly it identifies and tags your music.

 

[preproman]

 
it approaches the HE-6 in terms of power hunger.
 

I'm not sure where you got this information.  However,  that's not the case at all - not even close, which is a good thing to some.  I now have both and have played them on both of my amps.  There not even close to the HE-5LEs as being power hungry.  

 

[preproman]

  The above amplifier discussion is quite interesting. the he-560's sound can noticeably change with different amplifiers from personal experience. However, I have never experienced any audible sonic imperfections/distortions/noise/clipping even using my crappy cheap low-powered Bravo V3. The bass presence was lacking for sure, and the final sound signature was not to my liking. 
 
So I personally think that the power requirement claims and the he-560's difficulty to drive is quite exaggerated. Hifiman specifically stated that they engineered the HE-400i and HE-560 to be easier to drive than their older generation planar magnetic headphones.
 
I think that many people here are looking for a very certain specific sound signature that they enjoy & anything else is unacceptable for them. They will spend a lot of time trying to match amplifiers & feel like the he-560s are not performing optimally for their personal tastes with certain equipment matches. I think that a personal preference is playing a larger role here than the actual amplifier capabilities or performance.
 
You can definitely get great performance from the HE-560s using an inexpensive amplifier. The actual calculated power requirements are about half a watt, so 4+ watts is definitely supreme overkill. Nothing wrong with having that much power, but that much power is definitely not necessary to enjoy these headphones. I think 1-2 watts is more than enough with ample extra juice for 'headroom.'

+1
 
Good post

 

[hifimanrookie]

mandrake50: The marketing solution is NOT to build a better amp.

The marketing solution is to take advantage of the confusion and make money off of THAT.

The LOGICAL solution is to build a better amp. (IMO, of course)

YEP!!! Thats how it works

 

[Bill-P]

I'm not sure where you got this information.  However,  that's not the case at all - not even close, which is a good thing to some.  I now have both and have played them on both of my amps.  There not even close to the HE-5LEs as being power hungry.  

I'd agree that older Hifiman headphones may end up being harder to drive than the HE-560, but it has been my experience, with both the first HE-560 and the one that replaced it, that the HE-500 is noticeably easier to drive, and the HE-560 is just a small bit behind the HE-6 on the volume knob in terms of equal loudness.

This has been confirmed by some reviewers as well, that they feel the HE-560 is harder to drive than the HE-500 despite Hifiman's claim to it being otherwise.

Granted, though, I'd agree it won't require more than 4W of power. In fact, I'm sure about 2W per channel or so would be plenty for both the HE-6 and HE-560 even with high dynamic range music, provided that 2W is clean, stable, and sustainable.