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DAP-off! Astell&Kern, Sony, HiFiMan, Chord, FiiO, Lotoo, Soundaware, Hiby, Cayin & others
Jun 27, 2014 at 7:48 PM Post #482 of 2,125
@Advert Unfortunately I don't have the HM901 here any longer. However, for the UI, the Calyx would win but for sound, that would be closer I reckon.
 
Jun 27, 2014 at 7:58 PM Post #483 of 2,125
Just in case this would be good info for those that seek it, here is measurements done for AK240 vs DX90 with headphone load and without.  As  you can see, the DX90 numbers are better.
 
Credit to Shigzeo.
 
http://ohm-image.net/opinion/audiophile/rmaa-summary-ibasso-dx90-vs-astell-kern-ak240
 
 
 
Jun 27, 2014 at 8:38 PM Post #484 of 2,125
Opamps measure better than discrete circuits?  You don't say /facepalm
 
Joys of 110dB+ of negative feedback.  That said the DX90 is measuring no where near what the 1611/12 measure in a vacuum.
 
Jun 27, 2014 at 8:53 PM Post #486 of 2,125
silverears said:
  What makes the discrete circuits measure better?  Also, it seems you prefer discrete, what makes them better to you?
 
Can you explain this?  What does this cause?
Click to expand...

 
Opamps measure better... damn near always since they live in a world where you sell specs as performance and not performance as performance.
 
Dumbing feedback way down, it stabilizes the circuit and cranks measured performance by means of correction.
 
Getting good measurements with high feedback just isn't impressive.  Making a stable circuit with very low or no feedback is a much more difficult task.
 
Jun 27, 2014 at 8:56 PM Post #487 of 2,125
solude said:
   
Opamps measure better... damn near always since they live in a world where you sell specs as performance and not performance as performance.
 
Dumbing feedback way down, it stabilizes the circuit and cranks measured performance by means of correction.
 
Getting good measurements with high feedback just isn't impressive.  Making a stable circuit with very low or no feedback is a much more difficult task.
Click to expand...

Can  you post literature on this?  I would like to look into it.
 
Jun 27, 2014 at 9:00 PM Post #488 of 2,125
solude said:
  Opamps measure better than discrete circuits?  You don't say /facepalm
 
Joys of 110dB+ of negative feedback.  That said the DX90 is measuring no where near what the 1611/12 measure in a vacuum.
Click to expand...

Also, why does AK advertise those values then?  The numbers without the load.  Why don't they tell us what makes their players special instead of the numbers without load, and the dumbed down balanced noise rejection diagram of two DACs.  Also, why do they use two DACs if only one can do two channels in differential mode.  From AK100 to 120 as example.  Also, the Cowon P1's single ended does crosstalk better than 240's balanced numbers.
 
Jun 27, 2014 at 10:02 PM Post #489 of 2,125
2 separate DACs benefit from the same philosophy as discrete devices. less dynamic current limiting and cross pollination due to lots of circuitry drawing from the same tiny tracks on the chip. It's a different scenario than and will not show up on a typical steady state test. Using one channel of a stereo chip isn't as uncommon as you may expect. Chips can be great with bandwidth but bandwidth beyond 20k (without phase shift) has no useful purpose in audio other than how it may relate to feedback and even then you can have a fast feedback loop with overall bandwidth limiting. The steady state crosstalk #s your talking about are inconsequential.
 
I wouldn't be surprised if in use, that particular 2 chips in single phase mode setup may sound better than that a single 4ch chip in 2 ch differential mode even if it doesn't measure as well under steady state test conditions. Sort of less refined but more rhythmically realistic.
 
Jun 28, 2014 at 1:47 AM Post #490 of 2,125
Regardless, let me point out some things that are important about measurements (in no particular order and off the top of my head):
 
1. Measurements without comprehensive details about what was used to make the measurements and how it was set up, along with control tests, need to be treated with a huge grain of salt.
2. Even measurements using high-grade analysers require very carefully repeated tests and analysis to mean anything, as the analysers have many settings which can change the results. Even something as simple as a wire crossing nearby a power source or cable can change the results. Likewise, just changing the weighting of a measurement (eg: to A-weighting) will change the results considerably. A single spurious tone at one point in the entire frequency range will change a measurement, even if all it affects is one frequency to a degree that is effectively inaudible.
3. Measurements from RMAA are made using frequency sweeps. IMD distortion is measured using a pre-set pair of tones. Music does not consist of frequency sweeps or a single pair of pre-set tones and very likely the device will be used with components that have very different electrical characteristics than an analyser or sound card. That is: An amp's performance into an analyser with sweeps is often different to how it will perform with headphones with music playing, which provide a completely different load.
4. Negative feedback in circuits gives you better numbers, but increases distortion in the time domain, which required extremely expensive equipment to measure. It does impressive-looking numbers though.
5. Manufacturers don't provide more than basic (and essentially useless) measurements because the numbers can be misleading for the above reasons and don't relate to our experience when listening. Sometimes they provide the most impressive numbers in the most impressive weighting at the most impressive frequency to promote their products (and don't put the less impressive ones).
6. Unless measurements can be connected back to our listening experience, they don't tell us anything very useful. They are more useful in the reverse, when trying to track down the reasons for our experiences when listening with a product, such as why certain music sounds better on some headphones than others because of differences in the frequency response.
 
Jun 28, 2014 at 3:03 AM Post #491 of 2,125
currawong said:
  Regardless, let me point out some things that are important about measurements (in no particular order and off the top of my head):
 
1. Measurements without comprehensive details about what was used to make the measurements and how it was set up, along with control tests, need to be treated with a huge grain of salt.
2. Even measurements using high-grade analysers require very carefully repeated tests and analysis to mean anything, as the analysers have many settings which can change the results. Even something as simple as a wire crossing nearby a power source or cable can change the results. Likewise, just changing the weighting of a measurement (eg: to A-weighting) will change the results considerably. A single spurious tone at one point in the entire frequency range will change a measurement, even if all it affects is one frequency to a degree that is effectively inaudible.
3. Measurements from RMAA are made using frequency sweeps. IMD distortion is measured using a pre-set pair of tones. Music does not consist of frequency sweeps or a single pair of pre-set tones and very likely the device will be used with components that have very different electrical characteristics than an analyser or sound card. That is: An amp's performance into an analyser with sweeps is often different to how it will perform with headphones with music playing, which provide a completely different load.
4. Negative feedback in circuits gives you better numbers, but increases distortion in the time domain, which required extremely expensive equipment to measure. It does impressive-looking numbers though.
5. Manufacturers don't provide more than basic (and essentially useless) measurements because the numbers can be misleading for the above reasons and don't relate to our experience when listening. Sometimes they provide the most impressive numbers in the most impressive weighting at the most impressive frequency to promote their products (and don't put the less impressive ones).
6. Unless measurements can be connected back to our listening experience, they don't tell us anything very useful. They are more useful in the reverse, when trying to track down the reasons for our experiences when listening with a product, such as why certain music sounds better on some headphones than others because of differences in the frequency response.
Click to expand...

Glad someone finally said what I have been trying to say about spec sheets!!! THANKS!
 
Jun 28, 2014 at 7:13 AM Post #492 of 2,125
Which page can I find amos' comparison of these players with the Hugo?
 
Jun 28, 2014 at 8:14 AM Post #494 of 2,125
piercer said:
   
The HUGO is a DAC, not DAP so you can't just compare them directly.
Click to expand...

Yea, I have the Hugo, but the tilte mentions the Hugo but i dont read/see him using it in any of the posts i have read so perhaps I might have missed it. Any idea which page its in?
 
Jun 28, 2014 at 12:10 PM Post #495 of 2,125
joshuachew said:
Yea, I have the Hugo, but the tilte mentions the Hugo but i dont read/see him using it in any of the posts i have read so perhaps I might have missed it. Any idea which page its in?
Click to expand...


Might want to do a search within the thread... :)
 
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