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Review and Measurements of Ayre CODEX DAC & Amp

Blumlein 88

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#61
A bit like my old Ducati then.:p
One of my friends was letting me ride his nearly new Ducati. In the parking lot someone walked up asking about it. What was the question?

"Ooooh, a nice bike. A DUCATI. Have you owned it long enough for that to be a curse word? That's what mine became after a couple years."
 

svart-hvitt

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#62
Over-simplification. I hold JA in some regard for the measurements done. I hold him in some regard for posting those when the results were weak vs praise for the product under test. But he did have a way of papering over those. Often with saying despite measured artifacts the reviewer heard nothing wrong. Times like with the Ayre where he praises the results and you look and wonder wow I'd hate to see bad results if these are good were not common though did happen sometimes.

Back when he started measurements for S-phile he said he thought over time some patterns of what made for good gear would emerge. For myself knowing more about the reliability of sighted biased comparisons I know there was never any chance for that to happen. Whether he knew that or not then or how he thinks of it now I don't know.

I do trust his measurements he never seemed to abridge those. His measurements replicate elsewhere. His conclusions I'd not take without a grain of salt or my own conclusions substituted. So I trust some aspects of Mr. Atkinson, and look askance at others. So it isn't a black or white matter of trust. Trust isn't like being pregnant. I've never found trust to be that binary with most people.


;)
 

Shadrach

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#63
One of my friends was letting me ride his nearly new Ducati. In the parking lot someone walked up asking about it. What was the question?

"Ooooh, a nice bike. A DUCATI. Have you owned it long enough for that to be a curse word? That's what mine became after a couple years."
Yeah, but when they run right there is nothing better.;)
 

Jaimo

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#64
What a load of “Hot Ayre”

I could never understand why JA was such a Linn fanboy. If I remember correctly, he used a Linn Sondek as his reference turntable for many, many years. In fact, I purchased a Linn Sondek based on his reviews and after years of ownership concluded that it was a miserably engineered piece of junk.

Although I have no proof, I remain convinced that many establishment reviewers receive kickbacks from audio manufacturers in exchange for positive reviews.
 

anmpr1

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#65
And if you buy a classic Jaguar, you get electricals by Lucas.:D
Had a colleague with an XJS V12 drop top. Gorgeous car. Nothing electrical worked, and it cost a fortune for him to get it going. I'm not sure he ever did get everything working at the same time. But it looked so nice. Just sitting there. Which it mostly did.
 

restorer-john

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#66
And this is supposed to look like a sine wave:



I don't run this test anymore but when I did, devices like Topping DX7 produced this:

Let's be fair here and disclose your Topping DX7 shot above is 24 bit data.

The Ayre picture is 16 bit data @ -90dB and is behaving exactly as any converter would with so few bits/levels to play with.
1555201597696.png
 

amirm

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#67

March Audio

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#68
Let's be fair here and disclose your Topping DX7 shot above is 24 bit data.

The Ayre picture is 16 bit data @ -90dB and is behaving exactly as any converter would with so few bits/levels to play with.
View attachment 24890
Good point absolutely right, but I have seen these Stereophile plots look much cleaner on other products, sorry don't have one to hand.
 
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March Audio

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#69
Found one. Auralic vega 16 bit - 90.32dB

214Avegafig12.jpg


24bit for reference

214Avegafig13.jpg
 
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restorer-john

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#70
Good point but I have seen these Stereophile plots look much cleaner on other products
Absolutely. I'm not saying it is good, just that a comparison to 24 bit is unfair.
 

PierreV

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#71
Maybe this is a stupid question, but could it be intentional dithering gone... hmmm... not so well in an attempt to get a slightly different "brand sound"? Or is it just unwanted noise due to poor design? In many other cases I have had the impression that high-end stuff often sounded a bit different (and by that I don't mean better) on purpose. Of course, reviewers who would hear a vague difference in a more expensive product would automatically see it as better - they don't need much help there...

But still, looking around, it is amazing the number of devices that measure poorly, in some kind of 60 to 70 dB SINAD "sweet spot", with tons of harmonic distortion (or even not so harmonic one) and seem to have a happy customer base.

I am guilty of that myself as I have a few setups that I am almost sure would measure poorly to very poorly compared to what I see as my reference setups but that I enjoy listening to now and then.
 

trl

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#73
If this is a democratic process, I'd like to vote against it.
The sine wave measurement provides a quick overview of how a device performs, but tells us absolutely nothing as far as audibility is concerned. It's simply redundant with a full set of measurements.
"Perception of complex sound is a process carried out in everyday life situations and contributes in the way one perceives reality. Attempting to explain sound perception and how it affects human beings is complicated. Physics of simple sound can be described as a function of frequency, amplitude and phase. Psychology of sound, also termed psychoacoustics, has its own distinct elements of pitch, intensity and tibre. An interconnection exists between physics and psychology of hearing".
https://www.audiosciencereview.com/...can-we-trust-our-ears.3884/page-4#post-165431
Worth reading the entire article here: https://www.ncbi.nlm.nih.gov/pmc/ar...qWT2VR5QG9TEpUnet0IJYuN1z_iEis6j4ugxlsfXy1hrY.

Also, nice to read too: https://benchmarkmedia.com/blogs/application_notes/audio-rules-of-thumb.

My personal opinion about THD interpretation: if all the harmonics are lower than -90dB away from the fundamental sound, then we might not hear any undesired harmonics, even we can see them in those graphs. As per the signal/noise ratio or mains hum, below -100dB (references to 0dBFS) we should be just fine under most scenarios (now, depends on the internal gain and the sensitivity of our headphones or speakers).

In A/B tests an amp that measures badly (per my above paragraph) vs. an amp that measures perfectly will definitely sound different to our ears, but we can continue here the discussion anytime: https://www.audiosciencereview.com/forum/index.php?threads/can-we-trust-our-ears.3884/.
 

Frank Dernie

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#74
One of my friends was letting me ride his nearly new Ducati. In the parking lot someone walked up asking about it. What was the question?

"Ooooh, a nice bike. A DUCATI. Have you owned it long enough for that to be a curse word? That's what mine became after a couple years."
When I worked for Hesketh Racing we got some 'bikes to evaluate when designing Alexander's pet motorcycle project. It was 1978 and the bikes were a Kawasaki 1000, Yamaha 750 with shaft drive a classic BMW and a Ducati Darmah.
I had to design the frame of the Hesketh and rode all of them, the Ducati was enormously better than all the others.
I was amused by the paperwork. The BMW came with 3 huge comprehensive manuals and technical books. The Yamaha manual had advice such as "don't suddenly open throttle on wet pavement" and the Ducati only came with a wiring diagram!
The Ducati engine stopped when manoeuvering on one lock since the cables weren't quite long enough and the strain pulled out a plug...
 

edechamps

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#75
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#76
I need to voice my opinion, although I'm biased....
Yes, there is a lot of snake oil in the Audio Business, I'm not going to pay more for my speaker cables than my speakers, 2.5mm2 stranded wires are fine. And those that believe in "audio grade" fuses, I would like to sell the eiffel tower...
But there are also things that's hard to measure, simply because there are complex things going on and audio measurements methodes aren't really that advanced, mostly using static signals. The Human ear is an amazing thing, able to hear tiny details.
And negative feedback are not a good thing, but a solution to fix not that linear and usually bandwidth limited designs. Read up on Nelson Pass's Article at https://www.passdiy.com/project/articles/audio-distortion-and-feedback, there are also other good articles there. Anybody rememeber Matti Otala and his work ?
It is possible to design amplifier circuit with low distortion without using negative feedback, just not that easy.... My dac1541 typically get 0.003% THD at full signal level without negative feedback, it just takes 50 transistors per channel, most of them to ensure that the amplifying parts operate optimally....
And btw, if I had the choice between any old Ferrari and a new fancy Japanse sportscar, I'll take the Ferrari without a second of hesitation....
 

svart-hvitt

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#77
I need to voice my opinion, although I'm biased....
Yes, there is a lot of snake oil in the Audio Business, I'm not going to pay more for my speaker cables than my speakers, 2.5mm2 stranded wires are fine. And those that believe in "audio grade" fuses, I would like to sell the eiffel tower...
But there are also things that's hard to measure, simply because there are complex things going on and audio measurements methodes aren't really that advanced, mostly using static signals. The Human ear is an amazing thing, able to hear tiny details.
And negative feedback are not a good thing, but a solution to fix not that linear and usually bandwidth limited designs. Read up on Nelson Pass's Article at https://www.passdiy.com/project/articles/audio-distortion-and-feedback, there are also other good articles there. Anybody rememeber Matti Otala and his work ?
It is possible to design amplifier circuit with low distortion without using negative feedback, just not that easy.... My dac1541 typically get 0.003% THD at full signal level without negative feedback, it just takes 50 transistors per channel, most of them to ensure that the amplifying parts operate optimally....
And btw, if I had the choice between any old Ferrari and a new fancy Japanse sportscar, I'll take the Ferrari without a second of hesitation....
I encourage you to formulate your opinion in a way that makes sense in a way that can be followed up in a scientific way.

Your sportscar analogy would make sense if audio signals were as complex as an autocar in its environs.
 

DDF

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#78
Maybe this is a stupid question, but could it be intentional dithering gone... hmmm... not so well in an attempt to get a slightly different "brand sound"? Or is it just unwanted noise due to poor design? In many other cases I have had the impression that high-end stuff often sounded a bit different (and by that I don't mean better) on purpose. Of course, reviewers who would hear a vague difference in a more expensive product would automatically see it as better - they don't need much help there...

But still, looking around, it is amazing the number of devices that measure poorly, in some kind of 60 to 70 dB SINAD "sweet spot", with tons of harmonic distortion (or even not so harmonic one) and seem to have a happy customer base.

I am guilty of that myself as I have a few setups that I am almost sure would measure poorly to very poorly compared to what I see as my reference setups but that I enjoy listening to now and then.
I think we often fall victim to isolating the playback from the source. Fidelity in our gear should be the top priority so that high quality recordings shine. But so much of recorded music is "challenged" that its perfectly rational to appreciate that sonic flavoring provides a better experience, on average. Its about forsaking the 2 to 3 sigma for the mean.

Don't get me wrong, my Sota Saphire sits unused and I own Hypex, but I "get it" why someone would appreciate and favour secret sauce with their gear, even if they, for the most part, want accuracy. I think its easy to lose the forest for the trees.

Best attempt I've seen at analyzing this situation and doing something a bit more clinical about it:
https://www.innerfidelity.com/content/katzs-corner-episode-25-adventures-distortion
 

flipflop

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#79
But there are also things that's hard to measure, simply because there are complex things going on and audio measurements methodes aren't really that advanced, mostly using static signals.
Funny how a quote, from one of the articles in the post above yours, is still more relevant than ever 25 years later:
no one has ever, ever proved a consistently audible difference between two amplifiers having high input impedance, low output impedance, and low distortion, when operated at matched levels and not clipped
To say measurement methods aren't advanced when, for decades, they have been able to reliable predict whether or not amps (and DACs) can be distinguished from one another, is a bit silly. What more do you want?
 

amirm

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#80
Read up on Nelson Pass's Article at https://www.passdiy.com/project/articles/audio-distortion-and-feedback, there are also other good articles there.
The intro to feedback and distortion is very good there but outside of that, the case he is trying to make of higher order distortions doesn't hold water. Here is the $99 JDS Labs Atom headphone amplifier which has more power than most amps:



The dominant distortion is second harmonic at nearly -118 dB or so. The next harmonic is at -142 dB and nothing after that shows up. And this is with some 35 dB of FFT gain to make these distortions visible from way below noise floor.

Sure, you want to use less feedback and start with more linear circuits? We can have that. What we don't want to have is distortion coming out of our ears:

1555287003052.png


Here we have both low and high order distortion components without feedback. So clearly the case Nelson is trying to make is not correct. Maybe class B amplifiers have that characteristics but who uses those in audio?
 
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