[cjl]

I believe I could plug some HD 800s into my motherboard and have no difference between that and a $2000 amp.

I can say with quite a bit of confidence that this isn't always true - a lot of motherboard audio outputs will not have a large enough voltage swing for a high impedance headphone like HD800s, and often, they will have a lot of noise with a high sensitivity headphone. These are pretty easily diagnosed (and clearly audible) problems though, and you wouldn't need a $2k amp to fix them.

 

[jcx]

its hard to definitively draw a box around human hearing with easy to make and interpret signal measurements - hearing is complicated - which is different from the audiophile meme of hearing being "infinitely" more resolving than any measurement
 
for example there is "hearing below the noise floor" often cited - but that ignores full descriptions of "noise" - ignores our frequency discrimination that lets us hear other bands of low amplitude sounds even when there is a lot of noise in other frequency bands
 
a engineer would look at the human hearing noise floor in quiet over the whole range of hearing frequencies - and use that one strong limit on the ability to hear "errors" - harmonic, IMD, phase distortions of the waveforms that produce sounds below the limit in each frequency band are certainly inaudible
 
its possible for some electronics to keep errors below that limit - but no sound transducers like speakers or headphones can when simultaneously creating enjoyably "loud" SPL as is experienced in even live acoustic music performance
 
but the human hearing threshold vs frequency in quiet curve is an extreme over bounding limit - clearly the existence of better perceptual lossy codecs like AAC, Vorbis which may only use 6-7 bits "mantissa" per critical band (the ~20% wide frequency bands which our hearing seems to use) argues that practical thresholds for many waveform error's audibility is about 1% in each critical band considered separately, allowing for logarithmic ranging
 
 
but if we consider intermodulation distortion products it is possible to construct 2-tone test signals that allow detecting a IMD difference product lower than -80 dB re the pure tones level with a wide enough separation of the test tones frequencies from the IMD distortion product frequency
 
however you can't point to any tonal musical instruments that even taken together can make waveforms with the properties of those test signals
 
 
there are some attempts to make relatively simple links between engineering properties of waveforms, distortion and hearing - Dr Geddes and his Wife have credentials, have done some tests - http://www.gedlee.com/distortion_perception.htm
 
for electronics Geddes does propose hugely weighting low amplitude errors - you really, really don't want any crossover distortion in your amplifier output but he measured a number of cheap "chip amp" based consumer amps and found one of them did meet his low level distortion requirements - he has demoed his $4k? each speakers with a < $300 amp from Costco

 

[safulop]

Well I can name a couple of things that headphone amps can do which your soundcard can't.  Tube amplification, for one.  Definitely colors the sound in ways some folks like.  Another thing, although it is defunct now (sniff), is the channel crossfeed processing that was used by the geniuses at Headroom in all of their headphone amps.  I have two of them and I dearly love them, and I just found out today that they stopped making their own amps a couple of years ago.  I hate the idea of going back to headphone listening with no channel crossfeed.
 
But another concern when it comes to computer hardware is basically trust.  I, for one, don't trust Dell as far as stone's throw to make a laptop that has properly spec'ed parts and capabilities.  I mean, my keyboard bounces double letters and skips half of what I type, my wifi card is 1/3 of the proper speed.  What confidence could I put in their headphone jack?  And, despite being a scientist, I don't always live life to scientific "double-blind" standards.  Years ago when I finally splurged on an "audiophile" DAC to fix a CD player whose DAC died, I began to enjoy my CDs for the first time ever.  I don't require a double-blind test to experience increased enjoyment of sounds. Now I think the standards for basic DACs are more consistently implemented than they were in older CD players, but I still wouldn't trust the one in a cheap laptop.

 

[prot]

Well I can name a couple of things that headphone amps can do which your soundcard can't.  Tube amplification, for one.  Definitely colors the sound in ways some folks like.  Another thing, although it is defunct now (sniff), is the channel crossfeed processing that was used by the geniuses at Headroom in all of their headphone amps.  I have two of them and I dearly love them, and I just found out today that they stopped making their own amps a couple of years ago.  I hate the idea of going back to headphone listening with no channel crossfeed.

But another concern when it comes to computer hardware is basically trust.  I, for one, don't trust Dell as far as stone's throw to make a laptop that has properly spec'ed parts and capabilities.  I mean, my keyboard bounces double letters and skips half of what I type, my wifi card is 1/3 of the proper speed.  What confidence could I put in their headphone jack?  And, despite being a scientist, I don't always live life to scientific "double-blind" standards.  Years ago when I finally splurged on an "audiophile" DAC to fix a CD player whose DAC died, I began to enjoy my CDs for the first time ever.  I don't require a double-blind test to experience increased enjoyment of sounds. Now I think the standards for basic DACs are more consistently implemented than they were in older CD players, but I still wouldn't trust the one in a cheap laptop.

Dont think anyone is talking about cheap laptops .. or +5 years old ones. Those will prolly sound quite bad.
But the 8xx, 9xx and especially the newest 1150 chips from realtek are very good ... highend z97 motherboards from 2014-15 should sound very good .. e.g. see https://www.asus.com/ROG_ROG/MAXIMUS_VII_GENE/

 

[daleb]

  I can say with quite a bit of confidence that this isn't always true - a lot of motherboard audio outputs will not have a large enough voltage swing for a high impedance headphone like HD800s, and often, they will have a lot of noise with a high sensitivity headphone. These are pretty easily diagnosed (and clearly audible) problems though, and you wouldn't need a $2k amp to fix them.

Well, of course there are lots of horrible foxconn and the like motherboards, especially motherboards made for prebuilts with planned obsolescence in mind, but by "my motherboard," I mean an Asrock H97m Pro4, which has a Realtek ALC892 

 
 

Tube amplification, for one.  Definitely colors the sound in ways some folks like.

I disagree. I have never seen proof that tubes actually have the ability to color sound in any distinguishable way. Though if there is proof, I would love to see it.
 

http://www.tomshardware.com/reviews/high-end-pc-audio,3733.html

I feel pretty validated 

 
Of course, it doesn't have anywhere near the amount of test subjects, nor meets the standard of a peer reviewed article, but I'm happy. Thats the best I've seen on this subject, and thats all right with me. Thank you very much 

 

[safulop]

I had thought that the whole "tube amps sound different" thing was firmly established, supposedly due to the nonlinearity of tubes.  But I have no first-hand experience and no stake in the matter.  It is interesting to learn otherwise.

 

[safulop]

Wait, none of the amps in the article you linked appears to be a tube amp.  So all the ABX results don't address the question of tube amps right?

 

[arnyk]

  Wait, none of the amps in the article you linked appears to be a tube amp.  So all the ABX results don't address the question of tube amps right?

 
Actually the issue of tubed amps was resolved about 30 years ago.  A number of ABX tests of tube amp versus SS amp were run back then.
 
The tubed amps were not the modern abortion SET amps but real hifi gear designed to sound clean and avoid the problems of tubes wherever possible. The last generation of these tests were run in the 90s for Stereo Review Magazine.
 
What we found is that it took a really pretty good tubed amp (high end, very expensive) to duplicate fairly ordinary (mid-fi receiver) SS amps. Keeping the tubed amp running cleanly enough to compare favorably to the SS amps might take some work.
 
Tubes are constantly degrading, needing rebiasing and replacement. This which becomes more apparent when you compare them side-by-side to SS in a real comparison, not the flawed kids-game listening evaluations that the high end ragazines, web sites and most audiophiles diddle themselves (and the naive public) with.

 

[cjl]

   
I disagree. I have never seen proof that tubes actually have the ability to color sound in any distinguishable way. Though if there is proof, I would love to see it.

I think that depends on the design of the amp - you can make a perfectly transparent tube amp, or you can make one with clearly audible distortion. It all depends on what you're going for with your design. Of course, if you make one with audible distortion, it'll show up clearly on the measurements.

 

[arnyk]

Originally Posted by daleb 
 
I disagree. I have never seen proof that tubes actually have the ability to color sound in any distinguishable way. Though if there is proof, I would love to see it.
 
Quote:

  I think that depends on the design of the amp - you can make a perfectly transparent tube amp, or you can make one with clearly audible distortion. It all depends on what you're going for with your design. Of course, if you make one with audible distortion, it'll show up clearly on the measurements.

 
The evidence that tubes have the ability to color sound in any distinguishable way is a matter of scientific fact, demonstrated by any number of tube spec sheets and textbooks about designing tubed amps, further supported by technical tests of what should be highly colored amps in the pages of Stereophile Magazine for one, and easy enough to demonstrate by DBTs involving them.
 
A tubed amp that has as-used frequency response +/- 0.1 dB 20-20 KHz with a normal speaker load is not a slam dunk. If you have one, you probably paid a pretty penny for it!

 

[safulop]

Thanks Arny.  So, if tube amps sound so, how should I say this, distorted, why do so many people like them?  And you're saying that these "modern" tube headphone amps, phono pre-amps and such are really not doing a good job of amplification?  Essentially you're saying there is no good reason to mess around with tube amps.

 

[arnyk]

  Thanks Arny.  So, if tube amps sound so, how should I say this, distorted, why do so many people like them?  And you're saying that these "modern" tube headphone amps, phono pre-amps and such are really not doing a good job of amplification?  Essentially you're saying there is no good reason to mess around with tube amps.

 
I never ever said that all tube amps sound distorted.
 
And, ever since I saw the first truly nasty stupic lazy ugly girl who was married to some guy, I'll never try to explain other people's tastes or lack of it.
 
Are some people so vain that they will run right out to pick up a copy of the Emperor's Audio System, just to show their purchasing power. I think so.