ruthieandjohn
Stumbling towards enlightenment
(Formerly known as kayandjohn.)
Over my years on head-fi, I have had a fascination with high-quality portable audio from an iPhone or iPod, and over the years I have accumulated many portable DAC/amps:
* Chord Hugo (approximate price new $1,500)
* CEntrance HiFiM8 ($700)
* CEntrance HiFi Skyn ($400)
* Sony PHA-1 ($244)
* Sony PHA-3 ($998)
* V-MODA VAMP VERZA ($400)
* Beyerdynamic A 200p ($150).
Since I have all of these at hand together right now, it seemed useful to compare how each alters the sound of the iPhone by comparing sound from the iPhone directly vs. sound from the iPhone and through one or more of these DAC/amps, as well as comparing one DAC/amp to another with both being driven by the iPhone.
I have also developed a set of 10 comparative listening tests that I have used to compare over 50 different headphones, in over 50 three-way comparisons. These tests are described here. My goal was to apply these tests, or something similar, to rank order the improvement that each of these DAC/amps made over direct iPhone output.
I wanted to calibrate my ear to what changes to expect from a really good DAC/amp, so I began my comparison by picking what many acknowledge to be the best of the DAC/amps above, the Chord Hugo (certainly the most expensive as well), to compare with the case of no DAC/amp (i.e., direct from iPhone). I puzzled over which headphones to use for the comparison and started with the near-top-of-the-line Grado PS1000e. Grados are known as "fun" headphones, rather than accurate, and the PS1000e is their most resolving. The Grados are relatively easy to drive from an iPhone, having a sensitivity of SPL 99.8 dB at 1 mW (and a 32 ohm impedance).
My iPhone is a 5S, and the recording I started with was the first of the four I have used in the comprehensive tests above, the song "You're Going To Miss Me When I'm Gone," from the album One Foot In The Ether by the Band of Heathens. The album was played as a CD lossless rip at 44.1 Ksamples/sec, rather than the lossy AAC format that is standard with Apple iTunes. I compared with and without the Chord Hugo.
Well....
There were no night-and-day differences! I had to switch between the two cases (w vs. w/o Hugo) many times before I began to discern that the guitar that appears in the first few seconds seemed a bit farther away with the Hugo than without. I eventually spun that into a perception that the soundstage was a bit larger and more enveloping with the Hugo than without.
A bit more listening caused me to start to perceive that each instrument in the Hugo version might be just a bit more separated in space from other instruments than in the iPhone output directly, and eventually I developed the mental image of the band members being positioned inside the surface a balloon (where I, as listener, was positioned in the interior of the balloon, say a bit further from the band than center). For the Hugo, the distance to the instruments on the surface of the balloon was larger than without the Hugo. Hence, the better the DAC, the larger the balloon around me that had the instruments pasted to its inner wall.
I did not hear any differences in tonality, either in the bass drum, in the high frequency snare and cymbals, or in the guitar or piano (and I listened hard for them!)
It is hard to characterize just how great this difference was, but I can create sort of a hierarchical checklist:
So...
What am I to do to accentuate the differences? What sort of sounds better exploit the advantage offered by the best DAC/amp available to me than the small rock ensemble of lead guitar, rhythm guitar, bass, vocals (2), drum set, and piano? Or should I try different headphones than the PS1000e?
So far I have tried the following, but not found any combination that makes a bigger audible difference than what I had seen so far:
I started a comparison with the least expensive DAC/amp on the list, the Beyerdynamic A 200 p, to find that it indeed lay between the bare iPhone and the Hugo, and closer to the iPhone, in its ability to place the instruments inside a balloon (i.e., the balloon was smaller with the Beyerdynamic).
I will continue to listen to what should be the two extremes of this range of DAC/amps, in hopes of finding more clues to focus on for comparison, so that I might start ranking the effects of the various DAC/amps listed at the beginning of this. I will also listen to some sister models of Grado headphones, as I suspect one way of characterizing this small degree of difference would be something like "It is similar in difference to the difference one hears between the Grado RS1i vs. the RS2i") or some such.
All advice on comparison methods, what to listen for, sample music, or anything else is welcome. If I succeed in perceiving reliable differences, I will post the results, as I have the unique opportunity of comparing 8 portable DAC/amps (including direct from iPhone).
* Chord Hugo (approximate price new $1,500)
* CEntrance HiFiM8 ($700)
* CEntrance HiFi Skyn ($400)
* Sony PHA-1 ($244)
* Sony PHA-3 ($998)
* V-MODA VAMP VERZA ($400)
* Beyerdynamic A 200p ($150).
Since I have all of these at hand together right now, it seemed useful to compare how each alters the sound of the iPhone by comparing sound from the iPhone directly vs. sound from the iPhone and through one or more of these DAC/amps, as well as comparing one DAC/amp to another with both being driven by the iPhone.
I have also developed a set of 10 comparative listening tests that I have used to compare over 50 different headphones, in over 50 three-way comparisons. These tests are described here. My goal was to apply these tests, or something similar, to rank order the improvement that each of these DAC/amps made over direct iPhone output.
I wanted to calibrate my ear to what changes to expect from a really good DAC/amp, so I began my comparison by picking what many acknowledge to be the best of the DAC/amps above, the Chord Hugo (certainly the most expensive as well), to compare with the case of no DAC/amp (i.e., direct from iPhone). I puzzled over which headphones to use for the comparison and started with the near-top-of-the-line Grado PS1000e. Grados are known as "fun" headphones, rather than accurate, and the PS1000e is their most resolving. The Grados are relatively easy to drive from an iPhone, having a sensitivity of SPL 99.8 dB at 1 mW (and a 32 ohm impedance).
My iPhone is a 5S, and the recording I started with was the first of the four I have used in the comprehensive tests above, the song "You're Going To Miss Me When I'm Gone," from the album One Foot In The Ether by the Band of Heathens. The album was played as a CD lossless rip at 44.1 Ksamples/sec, rather than the lossy AAC format that is standard with Apple iTunes. I compared with and without the Chord Hugo.
Well....
There were no night-and-day differences! I had to switch between the two cases (w vs. w/o Hugo) many times before I began to discern that the guitar that appears in the first few seconds seemed a bit farther away with the Hugo than without. I eventually spun that into a perception that the soundstage was a bit larger and more enveloping with the Hugo than without.
A bit more listening caused me to start to perceive that each instrument in the Hugo version might be just a bit more separated in space from other instruments than in the iPhone output directly, and eventually I developed the mental image of the band members being positioned inside the surface a balloon (where I, as listener, was positioned in the interior of the balloon, say a bit further from the band than center). For the Hugo, the distance to the instruments on the surface of the balloon was larger than without the Hugo. Hence, the better the DAC, the larger the balloon around me that had the instruments pasted to its inner wall.
I did not hear any differences in tonality, either in the bass drum, in the high frequency snare and cymbals, or in the guitar or piano (and I listened hard for them!)
It is hard to characterize just how great this difference was, but I can create sort of a hierarchical checklist:
- Do I think that I could reliability tell in blind randomly-selected tests of the two cases (with Hugo vs. straight from iPhone w/o Hugo) that the current iteration was the same as or different than the previous one? Yes, with perhaps 85% certainty;
- Do I think that I could tell which was the Hugo and which was not, again in consecutive blind random tests? Yes, but with only about 67% certainty... I would expect to be wrong maybe 1/3 of the time!
- Do I think I could after leaving the setup and coming back after an hour or more, tell at first listen whether I was hearing with the Hugo or direct from the iPhone without the Hugo? No... no better than 50% (i.e. same as the random choice of flipping a coin).
So...
What am I to do to accentuate the differences? What sort of sounds better exploit the advantage offered by the best DAC/amp available to me than the small rock ensemble of lead guitar, rhythm guitar, bass, vocals (2), drum set, and piano? Or should I try different headphones than the PS1000e?
So far I have tried the following, but not found any combination that makes a bigger audible difference than what I had seen so far:
- Tried the Grado HP1000 HP1 headphone (the original and most linear of the Grados, from 1990);
- Tried the Grado RS2e headphone (brighter, smaller soundstage)
- Tried the Grado GS1000i headphone (I rank this as my best Grado, with the RS2e as second) - the GS series is known for its huge sound stage, and the GS1000i preserves a lot of high frequency content that perhaps would accentuate the effect of the Hugo;
- Tried the Sennheiser HD800 (notoriously hard to drive and hardly ever used alone with the iPhone, though the Chord Hugo is said to be a good source for these headphones -- the prediction was that the HD800 would sound horrible from the iPhone and great from the Hugo, but that was NOT the case!);
- Tried Saint Saens Organ Symphony as a more complicated piece than a rock group;
- Tried Beethoven's Third Symphony as a full orchestral piece rather than an orchestra backing an organ.
I started a comparison with the least expensive DAC/amp on the list, the Beyerdynamic A 200 p, to find that it indeed lay between the bare iPhone and the Hugo, and closer to the iPhone, in its ability to place the instruments inside a balloon (i.e., the balloon was smaller with the Beyerdynamic).
I will continue to listen to what should be the two extremes of this range of DAC/amps, in hopes of finding more clues to focus on for comparison, so that I might start ranking the effects of the various DAC/amps listed at the beginning of this. I will also listen to some sister models of Grado headphones, as I suspect one way of characterizing this small degree of difference would be something like "It is similar in difference to the difference one hears between the Grado RS1i vs. the RS2i") or some such.
All advice on comparison methods, what to listen for, sample music, or anything else is welcome. If I succeed in perceiving reliable differences, I will post the results, as I have the unique opportunity of comparing 8 portable DAC/amps (including direct from iPhone).
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