Tuttle et al v Audiophile Music Direct

[The Computer Audiophile]

Just now, Iving said:

 

I don't.

 

imo patronising remark

Not sure why you're taking this personal. 

 

What does provenance tell you that you want to know, if not indicative of sound quality?

[Iving]

1 minute ago, The Computer Audiophile said:

Not sure why you're taking this personal. 

 

I'm not. Hope to die.

 

1 minute ago, The Computer Audiophile said:

What does provenance tell you that you want to know, if not indicative of sound quality?

 

Already explained. I want to understand things so that I can make up my own mind.

 

Especially true wrt purchasing decisions.

[The Computer Audiophile]

3 minutes ago, Iving said:

Already explained. I want to understand things so that I can make up my own mind.

 

What does AAA, ADD, ADA, tell you that you can use to make up your own mind? It certainly helps you understand the process a recording went through, but that's only helpful if your collecting recordings that went through a certain process. It has zero to do with listening. 

[The Computer Audiophile]

If I'm not mistaken, we all want the best sounding recordings. I don't think armchair engineers looking over real engineers' shoulders, helps the cause. 

[PYP]

I'm curious about provenance, just as I am about knowing more about the recording process.  Where was the album recorded and mastered?  Microphones used and even placement.  Just out of (intellectual?) curiosity and the desire to learn more.  

 

For some recordings, you can tell that there is a difference track to track.  With a little digging, you might find out that they were recorded in different location and/or mastered by different people or places.  I find all of that interesting.  And not because it influences what I hear.  I'm streaming all of this stuff and not purchasing any of it, but if I did purchase a download I wouldn't base a purchase on anything else than my ears.

 

 

[Norton]

3 minutes ago, The Computer Audiophile said:

People are mistaking provenance for sound quality. 

But they are not mutually exclusive, you can have both as sources of information.

The trouble is that the format of the distributed product cannot be disregarded  and in the absence of any other information on the recording & production chain, will itself influence perception of SQ.

[The Computer Audiophile]

2 minutes ago, PYP said:

I'm curious about provenance, just as I am about knowing more about the recording process.  Where was the album recorded and mastered?  Microphones used and even placement.  Just out of (intellectual?) curiosity and the desire to learn more.  

 

For some recordings, you can tell that there is a difference track to track.  With a little digging, you might find out that they were recorded in different location and/or mastered by different people or places.  I find all of that interesting.  And not because it influences what I hear.  I'm streaming all of this stuff and not purchasing any of it, but if I did purchase a download I wouldn't base a purchase on anything else than my ears.

 

 

I absolutely love this information as well. 

[Iving]

11 minutes ago, The Computer Audiophile said:

What does AAA, ADD, ADA, tell you that you can use to make up your own mind? It certainly helps you understand the process a recording went through, but that's only helpful if your collecting recordings that went through a certain process. It has zero to do with listening. 

 

I agree quite a lot.

 

I am a lot like @JoshM.

 

I rip, listen and archive to my Library more CDs than most people have had hot dinners.

 

I have my own tagging system for "TBVO", and SPARS codes rarely if ever feature in my thinking.

 

Doesn't mean that:

 

If I buy a record only interested in digits-free ones, I don't want to know provenance to be assured digits-free. I don't care what MoFi or other hobbyists say about DSD records. I just don't want to buy them.

 

If I were in market for non-CD digital products I wouldn't want to know their attributes and the "steps" taken to produce what I am buying. Reasons already explained.

[Iving]

5 minutes ago, The Computer Audiophile said:

I don't think armchair engineers looking over real engineers' shoulders, helps the cause. 

 

All experts produce what they produce with the world watching. Many produce to spec. Real experts aren't worried about inspection. They have justifiable confidence.

 

In most legal systems retail products have to be correctly/adequately described. 

[The Computer Audiophile]

1 minute ago, Iving said:

If I buy a record only interested in digits-free ones, I don't want to know provenance to be assured digits-free. I don't care what MoFi or other hobbyists say about DSD records. I just don't want to buy them.

 

 

Why do you only purchase AAA records? Does AAA tell you something about the sound quality?

[The Computer Audiophile]

4 minutes ago, Iving said:

All experts produce what they produce with the world watching. Many produce to spec. Real experts aren't worried about inspection. They have justifiable confidence.

Not sure I live in the same world as you. 

 

I don't think anyone, other than the engineers working on Beyonce's new album, know how it was made. The world is not watching. The album wasn't produced to any spec. If on the other hand, the world demanded she release an album that was AAA, or they wouldn't purchase it, she would've produced an AAA album even if it sounded worse. 

 

Companies have to sell their goods. If the misguided public likes AAA solely because it says AAA, AAA is what they'll sell. 

[Iving]

9 minutes ago, The Computer Audiophile said:

Why do you only purchase AAA records?

 

Good and fair question.

 

A lot of it is I am a child of my time.

 

Even tho' I wasn't yet born I would rather listen to Dixie, Swing etc off shellac than any digital source.

 

9 minutes ago, The Computer Audiophile said:

Does AAA tell you something about the sound quality?

 

Not especially. Analogue is implicit. That's what I enjoy.

[Iving]

1 minute ago, The Computer Audiophile said:

Not sure I live in the same world as you. 

 

I don't think anyone, other than the engineers working on Beyonce's new album, know how it was made. The world is not watching. The album wasn't produced to any spec. If on the other hand, the world demanded she release an album that was AAA, or they wouldn't purchase it, she would've produced an AAA album even if it sounded worse. 

 

Companies have to sell their goods. If the misguided public likes AAA solely because it says AAA, AAA is what they'll sell. 

 

beyonce a bit hypothetical for me

[The Computer Audiophile]

Just now, Iving said:

 

Good and fair question.

 

A lot of it is I am a child of my time.

 

Even tho' I wasn't yet born I would rather listen to Dixie Swing off shellac than any digital source.

 

 

Not especially. Analogue is implicit. That's what I enjoy.

Understood. It's great that you enjoy them.

 

 

[The Computer Audiophile]

Just now, Iving said:

 

beyonce a bit hypothetical for me

In the real world, she released a new album.

[Iving]

Just now, The Computer Audiophile said:

In the real world, she released a new album.

 

ty i feel educated!

[PYP]

6 minutes ago, Iving said:

 

beyonce a bit hypothetical for me

No worries.  I'm certain Bey won't be offended.  

[Rt66indierock]

1 hour ago, Iving said:

 

All experts produce what they produce with the world watching. Many produce to spec. Real experts aren't worried about inspection. They have justifiable confidence.

 

In most legal systems retail products have to be correctly/adequately described. 

 

You are incorrect as far as United States goes. There is a lot of case law that states repeatedly “no reasonable consumer would believe that.” You can’t even bring this case in my home state of Arizona.

 

I can’t imagine any circumstances where your dixie swing master tapes were stored properly. Heat, humidity floods and hurricanes saw to that decades ago.

[Rt66indierock]

1 hour ago, The Computer Audiophile said:

Not sure I live in the same world as you. 

 

I don't think anyone, other than the engineers working on Beyonce's new album, know how it was made. The world is not watching. The album wasn't produced to any spec. If on the other hand, the world demanded she release an album that was AAA, or they wouldn't purchase it, she would've produced an AAA album even if it sounded worse. 

 

Companies have to sell their goods. If the misguided public likes AAA solely because it says AAA, AAA is what they'll sell. 

 

My only interest in this was when I saw the words audiophile and existential crisis. I was laid up with a badly sprained ankle and had time to look at the case. And of course, if there is an existential crisis my first thought is what can I do to make it worse.

To me the problem with all the angst is this. If you want X album and your only choice is a digital step, or album can’t be reissued. What’s the choice? A reasonable consumer would know this and judge it on sound quality. Or maybe not buy it. A reasonable consumer would not file a lawsuit.

 

Mobile Fidelity’s database is nice. I’m happy Foghat’s Fool for the City still exists on tape. But yesterday I heard Barbara Keith’s All Along the Watchtower cover and Dave Alvin and Jimmy Dale Gilmore’s Downey to Lubbock on the Bose (gasp) Sirrus XM system in my Mazda CX-9. You can either hear the music or you can’t.

[Iving]

2 hours ago, Rt66indierock said:

You are incorrect as far as United States goes. There is a lot of case law that states repeatedly “no reasonable consumer would believe that.” You can’t even bring this case in my home state of Arizona.

 

Thank you

 

What you quote of mine was part of a conversation with Chris where he had just prior said, "don't think armchair engineers looking over real engineers' shoulders, helps the cause. "

 

So what I was saying

All experts produce what they produce with the world watching. Many produce to spec. Real experts aren't worried about inspection. They have justifiable confidence.

 

had more to do with whether it's reasonable from an ordinary (consumer) pov that buyers might be allowed to understand how their (retail) products are built than it had to do with the legal context in USA which I already confessed I know next to nothing.

 

2 hours ago, Rt66indierock said:

I can’t imagine any circumstances where your dixie swing master tapes were stored properly. Heat, humidity floods and hurricanes saw to that decades ago.

 

Quite so. Two words. Joe Bussard.

 

+ why some shellac discs are worth their weight in gold.

[Qhwoeprktiyns]

5 hours ago, The Computer Audiophile said:

If I'm not mistaken, we all want the best sounding recordings. I don't think armchair engineers looking over real engineers' shoulders, helps the cause. 

 

If we make the parallel with equipment, I am sure you would agree that many audiophiles take into consideration design aspects when choosing equipment. Many find it interesting to know what makes a product unique, what problems it's trying to solve, even if we know the proof is in the pudding. At the very least, we want to be reassured that we are getting the best "technology" available. "This sounds good" is never really good enough, many of us are curious to understand what's under the hood. It's rare nowadays for a manufacturer not to share technical information. Why would this be different with recordings (especially those geared towards "audiophiles") ? 

 

I have included at the bottom of this post the product description of the Holo May DAC (which I was recently reading), copied from their website: https://www.kitsunehifi.com/product/holo-audio-may-dac/.

 

You've got to be an armchair engineer to understand any of it! For the many of us who do not understand what all this means, it may still influence us and determine what we pay attention to.

 

They conclude by explaining:

 

Quote

This new DAC “May” is the design of a new generation, it’s HoloAudio’s finest technology all designed by Jeff Zhu, the engineer behind these great products. It’s a full discrete R2R type of audio decoder and does not have off the shelf-DAC chip! This is a bespoke custom-designed core DUAL MONO DAC modules that are truly a breakthrough with technology for any DAC chip today. The May is here to achieve new heights, new dynamics and simply a full spectrum of audio to please the aural senses.

 

 

 

So two questions:

- how would you feel if you found out that the technical description of one of the equipment you purchased was intentionally deceiving/false ?

- would you go as far as suggest that manufacturers don't publish this type of information so as not to influence our choices ?

 

--- May DAC description ---

 

Some noted features:

The May DAC (all three models) will also support DSD1024 native and PCM 1.536MHz output! Theoretically it can do DSD2048 and PCM 3.072Mhz however is untested at this time. Also, we have worked hard to reduce the common click noise with all dacs when switching from DSD to PCM. This sound click sound has been reduced significantly with a special circuit design. The May DAC has the new and exclusive USB Enhanced module (L2 and KTE ONLY) which has our FPGA with the new Titanis 2.0  and custom firmware to improve USB Eye Pattern and reduce latency to near zero as well as reduce jitter to very very low levels. The USB module has completely new code written to optimize performance and reduce latency significantly. Low frequency performance (-40db) is also improved. The “enhanced” USB xmos module is twice as powerful/capable as the one that is used in the Spring2.

New improved power supply circuit with high performance multi stage regulation circuit using Rubycon ZLH caps, Panasonic FC, Vishay Caps or L2/KTE models with our exclusive HoloAudio Branded Caps (KTE model unique custom proprietary caps to replace Vishay caps)

We are no longer using common LVDS chipset and are now using a custom 4way circuit that isolates each line which further improves sound quality. such as the MCLK is isolated from data line and this improves jitter spec. Also there are TWO i2s ports in the May dac. Each one can be individually configured pin outs to support all i2s products on the market.

The May and KTE version of the May DAC also is with a CNC machined aluminum remote control! Standard with all three models.

The KTE version has OCC copper wire replaced with 1.5mm pure silver wire. 1.5mm Silver wire is soldered direct to the pcbs with highest grade audio solder. Silver Rhodium Faston connectors used at IEC input.

The May is a DUAL mono DAC. so there is a dedicated Dac Module for Left Channel and a dedicated Dac Module for Right Channel. Also each channel is individually powered by it’s dedicated Otype FLATWIRE transformer found in all three models. We have found after careful testing this new transformer type outperforms ALL transformers we have ever tested to this date. Near zero leakage, improved dynamics and overall spectacular performance. They are handmade for this dac specifically and delivery world class performance you would expect.

May DAC also has a new screen on the front that appears the same as the Spring2 on initial glance…. Font size is bigger than Spring2 but smaller than Spring1. Also you can see the CD track-time information is displayed when using spdif inputs!!!. This is done by extracting additional data from SPDIF. This a part of CD red book standard but nobody notices this and often forgets this cool feature or doesn’t know how to extract the data!. This will lead a fashion for other DAC developer to support this feature… customers will surely love this feature albeit subtle. The screen is much better contrast and viewing angles and one of the first things one may notice.

The May also has a front power button now! It’s been a request by many customers and gone are the days of a good old reach around to get the dac to be turned on! As mentioned before above… The DAC has a soft start circuit!! So don’t fret, it takes a moment for it to charge up and pull power without blowing the fuse!! It actually uses the same exact value of fuse that our Spring1 and Spring2 has! But two transformers! If we don’t have a soft start a couple issues can happen… one being a blown fuse from power surge, and another simply having possible pop noises. No chance of these things happening. We have carefully designed the circuit to have a zero compromise design.

Technical Information about our Custom PLL circuit:-

Now the May is implemented with femto clocks, and also new discrete ultra high performance voltage regulators. It has an advanced PLL (phase lock loop) circuit that is completely custom built for ultra high performance anti jitter performance. Even the highest levels of jitter are near eliminated which delivers world class performance. Using Crystek VXCO clocks that will take any incoming digital signal an reclock it to perfection! This feature can be enabled or disabled to test and prove it’s performance is truly spectacular. Note: this is NOT an off the shelf PLL, but it’s truly the most powerful PLL found in a DAC. Or at least to our knowledge it’s the most powerful PLL ever.. Spdif usually is a not a good protocol because it’s very old and dated! It was designed in 70s together with CD with Sony and Philips. As you may know, It encodes the data signal together with clock signal so it can be transferred by a one-core cable. It makes the cable easy to source, but to encode the data to clock at the transmit side and decode the clock from data at the receiving side, creates jitter. Toslink is a fiber glass version of Spdif. So Toslink adds even more jitter while doing electronic to photo and photo to electronic translation. So people will see clearly that I2S is usually better than SPDIF because I2S has 4 separate signal, 3 clocks 1 data. So it does not have encoding-decoding stuff thus has a better jitter performance. This is important to know this.

A common technique to improve the clock signal from SPDIF is PLL. A PLL is to use a local clock generator to track the source clock. You know jitter is actually a time deviation problem. For example, the fist period frequency is 44101Hz and the following second period is 44099Hz. Thus it has 2/44100 jitter. A PLL is to smooth the time deviation of clock. So after the PLL, it can be 44100.9-44099.1(this is a weak/poor performing PLL). Or it can be 44100.1-44099.9(this is a strong performance PLL). Usually, a SPDIF chip, like AK4118A, has an internal PLL. AK4118A is good chip compared to other Spdif receiver chip and it marks 50ps jitter. It’s the best we can get from a commercial chip. But it’s far from ideal, and definitely not enough for a HiFi standard we are implementing in the May dac. So we need a significantly stronger performing PLL. If the PLL is strong enough, it can smooth the 44101-44009 source clock to 44100.00001-44009.99999(very close to ideal 44100-44100)

But to make a stronger PLL is not easy, it’s actually incredibly difficult. First you need a powerful local clock source. A fixed clock can’t be used because it need to be adjusted to follow source clock rate. A common solution to use a VCO(voltage controlled oscillator). VCO is made by resistors, capacitor and inductors. The cost is low but performance is not so great. So, a better solution is to use VCXO(Voltage controlled crystal oscillator), it uses crystal as oscillator and crystal is a far better oscillator. The VCXO we used in May is Crystek’s CVHD-957. This the best VCXO we can get now.

The second hard problem is, the data need to be synchronized with clock. For example, the source has 44101-44099 clock from Spdif, that also mean it has 44101 samples in first period and 44099 samples in second period. So a good local 44100-44100 clock will have to throw away one sample in first period and lack one sample in second period. An easy fix to it is to use digital filter to smooth the data and it calls ASRC, but ASRC actually modified the data. So after ASRC, the data is modified thus not bit perfect anymore. And digital filter can also generate time domain problems like ringing artifacts. So, a digital filter is not a good way to solve this problem, or you can say, it solve a problem by introduce another problem.

May uses a fifo buffer to store the extra one sample in first period and release it in second period. So it has no harm to data. The difficulty for this design is how to manage fifo buffer. It can be a problem when you have a long-term jitter. And long-term jitter is actually called low frequency phase noise in a frequency domain point of view. To explain it easily, let’s take a example, a long term jitter can be like this, 44101-44102-44103-44104-44105-44104-44103-44102-44101-44100-44099-44098-44097-44096-44095-44096-44097-44098-44099-44100. So you see, it will have 25 extra sample in first ten periods, so the fifo buffer need to able store enough of them and release it in next 10 periods.

So, as a result, May’s PLL’s corner frequency is set to 0.05-0.1Hz in 3-orders. Than means it can reduce a 10s long term jitter by 90%, 1s period jitter by 99%, 0.1s period jitter by 99.9%…… That maybe the most powerful PLL in this industrial. And the most important is, it won’t lose data, it can still locking the source while huge jitter comes in. When you compared other similar PLL in the industrial, you can see it simply unlock the signal when huge jitter comes in. So, in that way, it simply stop you from listening, it tells you there is a problem but not solve it.

I have attached 2 pictures. The AP equipment generate huge jitters to SPDIF(750ns, 1KHz). If the PLL turned off, you will see an very ugly spectrum that means the jitter distorted the analog signal badly. The other picture turn on the PLL, and you can see it beautifully removed almost all the jitters. Compared to other competitors PLL. They won’t remove the jitter so clean, and simply unlock the signal for more than 10ns jitters.

 

More about the May Dac.

The new generation of linear compensation technology solves the accuracy errors caused by resistor
tolerance, after compensation, reaching a variance of 0.00005% tolerance accuracy.

Proprietary anti-jitter technology that provides a full amplitude of anti-jitter without increasing noise floor
and other undesirable effects.

Based on this new generation of technology May “梅” can provide a SINAD of >115dB and a dynamic range
of >130dB, which represents the performance limit reached by today’s most advanced R2R architecture
DAC.

Using the ultimate performance of PLL+FIFO technology, provides 0.1Hz Third-Order low-pass ability to
inhibit jitter. It also uses a high-performance femtosecond VCXO as the PLL clock source. Under the premise
of being almost immune to the front-end jitter, it can also lock up to 1.5us-2us @ 1KHz signal with high
jitter. (It can lock up to 1.5us-2us @ 1kHz signal with high jitter on the premise of almost being immune
front-end jitter).

Dual Mono DAC L/R channels are independently powered by their own dedicated transformer in the PSU
chassis. This provides better channel separation and more accurate sound stage.

Official Support USB and I2S up to DSD1024 and PCM1.536MHz sample rate.

The USB interface uses proprietary firmware with ultra-low latency, a highly reliable data transmission, ideal
USB eye pattern measurements that contributes to 2-4 times higher performance than official firmware.

Two sets of independent HDMI-I2S input interfaces are provided, and each set of I2S has a four-way
independent circuit, as opposed to standard LVDS chip, making I2S clock signals subject to lower
interference and lower jitter. In addition, each group of I2S inputs can be configured with specific pinout
configuration, making it compatible with most of the HDMI-I2S digital devices on the market.

[The Computer Audiophile]

19 minutes ago, hopkins said:

 

If we make the parallel with equipment, I am sure you would agree that many audiophiles take into consideration design aspects when choosing equipment. Many find it interesting to know what makes a product unique, what problems it's trying to solve, even if we know the proof is in the pudding. At the very least, we want to be reassured that we are getting the best "technology" available. "This sounds good" is never really good enough, many of us are curious to understand what's under the hood. It's rare nowadays for a manufacturer not to share technical information. Why would this be different with recordings (especially those geared towards "audiophiles") ? 

 

I have included at the bottom of this post the product description of the Holo May DAC (which I was recently reading), copied from their website: https://www.kitsunehifi.com/product/holo-audio-may-dac/.

 

You've got to be an armchair engineer to understand any of it! For the many of us who do not understand what all this means, it may still influence us and determine what we pay attention to.

 

They conclude by explaining:

 

 

 

 

So two questions:

- how would you feel if you found out that the technical description of one of the equipment you purchased was intentionally deceiving/false ?

- would you go as far as suggest that manufacturers don't publish this type of information so as not to influence our choices ?

 

--- May DAC description ---

 

Some noted features:

The May DAC (all three models) will also support DSD1024 native and PCM 1.536MHz output! Theoretically it can do DSD2048 and PCM 3.072Mhz however is untested at this time. Also, we have worked hard to reduce the common click noise with all dacs when switching from DSD to PCM. This sound click sound has been reduced significantly with a special circuit design. The May DAC has the new and exclusive USB Enhanced module (L2 and KTE ONLY) which has our FPGA with the new Titanis 2.0  and custom firmware to improve USB Eye Pattern and reduce latency to near zero as well as reduce jitter to very very low levels. The USB module has completely new code written to optimize performance and reduce latency significantly. Low frequency performance (-40db) is also improved. The “enhanced” USB xmos module is twice as powerful/capable as the one that is used in the Spring2.

New improved power supply circuit with high performance multi stage regulation circuit using Rubycon ZLH caps, Panasonic FC, Vishay Caps or L2/KTE models with our exclusive HoloAudio Branded Caps (KTE model unique custom proprietary caps to replace Vishay caps)

We are no longer using common LVDS chipset and are now using a custom 4way circuit that isolates each line which further improves sound quality. such as the MCLK is isolated from data line and this improves jitter spec. Also there are TWO i2s ports in the May dac. Each one can be individually configured pin outs to support all i2s products on the market.

The May and KTE version of the May DAC also is with a CNC machined aluminum remote control! Standard with all three models.

The KTE version has OCC copper wire replaced with 1.5mm pure silver wire. 1.5mm Silver wire is soldered direct to the pcbs with highest grade audio solder. Silver Rhodium Faston connectors used at IEC input.

The May is a DUAL mono DAC. so there is a dedicated Dac Module for Left Channel and a dedicated Dac Module for Right Channel. Also each channel is individually powered by it’s dedicated Otype FLATWIRE transformer found in all three models. We have found after careful testing this new transformer type outperforms ALL transformers we have ever tested to this date. Near zero leakage, improved dynamics and overall spectacular performance. They are handmade for this dac specifically and delivery world class performance you would expect.

May DAC also has a new screen on the front that appears the same as the Spring2 on initial glance…. Font size is bigger than Spring2 but smaller than Spring1. Also you can see the CD track-time information is displayed when using spdif inputs!!!. This is done by extracting additional data from SPDIF. This a part of CD red book standard but nobody notices this and often forgets this cool feature or doesn’t know how to extract the data!. This will lead a fashion for other DAC developer to support this feature… customers will surely love this feature albeit subtle. The screen is much better contrast and viewing angles and one of the first things one may notice.

The May also has a front power button now! It’s been a request by many customers and gone are the days of a good old reach around to get the dac to be turned on! As mentioned before above… The DAC has a soft start circuit!! So don’t fret, it takes a moment for it to charge up and pull power without blowing the fuse!! It actually uses the same exact value of fuse that our Spring1 and Spring2 has! But two transformers! If we don’t have a soft start a couple issues can happen… one being a blown fuse from power surge, and another simply having possible pop noises. No chance of these things happening. We have carefully designed the circuit to have a zero compromise design.

Technical Information about our Custom PLL circuit:-

Now the May is implemented with femto clocks, and also new discrete ultra high performance voltage regulators. It has an advanced PLL (phase lock loop) circuit that is completely custom built for ultra high performance anti jitter performance. Even the highest levels of jitter are near eliminated which delivers world class performance. Using Crystek VXCO clocks that will take any incoming digital signal an reclock it to perfection! This feature can be enabled or disabled to test and prove it’s performance is truly spectacular. Note: this is NOT an off the shelf PLL, but it’s truly the most powerful PLL found in a DAC. Or at least to our knowledge it’s the most powerful PLL ever.. Spdif usually is a not a good protocol because it’s very old and dated! It was designed in 70s together with CD with Sony and Philips. As you may know, It encodes the data signal together with clock signal so it can be transferred by a one-core cable. It makes the cable easy to source, but to encode the data to clock at the transmit side and decode the clock from data at the receiving side, creates jitter. Toslink is a fiber glass version of Spdif. So Toslink adds even more jitter while doing electronic to photo and photo to electronic translation. So people will see clearly that I2S is usually better than SPDIF because I2S has 4 separate signal, 3 clocks 1 data. So it does not have encoding-decoding stuff thus has a better jitter performance. This is important to know this.

A common technique to improve the clock signal from SPDIF is PLL. A PLL is to use a local clock generator to track the source clock. You know jitter is actually a time deviation problem. For example, the fist period frequency is 44101Hz and the following second period is 44099Hz. Thus it has 2/44100 jitter. A PLL is to smooth the time deviation of clock. So after the PLL, it can be 44100.9-44099.1(this is a weak/poor performing PLL). Or it can be 44100.1-44099.9(this is a strong performance PLL). Usually, a SPDIF chip, like AK4118A, has an internal PLL. AK4118A is good chip compared to other Spdif receiver chip and it marks 50ps jitter. It’s the best we can get from a commercial chip. But it’s far from ideal, and definitely not enough for a HiFi standard we are implementing in the May dac. So we need a significantly stronger performing PLL. If the PLL is strong enough, it can smooth the 44101-44009 source clock to 44100.00001-44009.99999(very close to ideal 44100-44100)

But to make a stronger PLL is not easy, it’s actually incredibly difficult. First you need a powerful local clock source. A fixed clock can’t be used because it need to be adjusted to follow source clock rate. A common solution to use a VCO(voltage controlled oscillator). VCO is made by resistors, capacitor and inductors. The cost is low but performance is not so great. So, a better solution is to use VCXO(Voltage controlled crystal oscillator), it uses crystal as oscillator and crystal is a far better oscillator. The VCXO we used in May is Crystek’s CVHD-957. This the best VCXO we can get now.

The second hard problem is, the data need to be synchronized with clock. For example, the source has 44101-44099 clock from Spdif, that also mean it has 44101 samples in first period and 44099 samples in second period. So a good local 44100-44100 clock will have to throw away one sample in first period and lack one sample in second period. An easy fix to it is to use digital filter to smooth the data and it calls ASRC, but ASRC actually modified the data. So after ASRC, the data is modified thus not bit perfect anymore. And digital filter can also generate time domain problems like ringing artifacts. So, a digital filter is not a good way to solve this problem, or you can say, it solve a problem by introduce another problem.

May uses a fifo buffer to store the extra one sample in first period and release it in second period. So it has no harm to data. The difficulty for this design is how to manage fifo buffer. It can be a problem when you have a long-term jitter. And long-term jitter is actually called low frequency phase noise in a frequency domain point of view. To explain it easily, let’s take a example, a long term jitter can be like this, 44101-44102-44103-44104-44105-44104-44103-44102-44101-44100-44099-44098-44097-44096-44095-44096-44097-44098-44099-44100. So you see, it will have 25 extra sample in first ten periods, so the fifo buffer need to able store enough of them and release it in next 10 periods.

So, as a result, May’s PLL’s corner frequency is set to 0.05-0.1Hz in 3-orders. Than means it can reduce a 10s long term jitter by 90%, 1s period jitter by 99%, 0.1s period jitter by 99.9%…… That maybe the most powerful PLL in this industrial. And the most important is, it won’t lose data, it can still locking the source while huge jitter comes in. When you compared other similar PLL in the industrial, you can see it simply unlock the signal when huge jitter comes in. So, in that way, it simply stop you from listening, it tells you there is a problem but not solve it.

I have attached 2 pictures. The AP equipment generate huge jitters to SPDIF(750ns, 1KHz). If the PLL turned off, you will see an very ugly spectrum that means the jitter distorted the analog signal badly. The other picture turn on the PLL, and you can see it beautifully removed almost all the jitters. Compared to other competitors PLL. They won’t remove the jitter so clean, and simply unlock the signal for more than 10ns jitters.

 

More about the May Dac.

The new generation of linear compensation technology solves the accuracy errors caused by resistor
tolerance, after compensation, reaching a variance of 0.00005% tolerance accuracy.

Proprietary anti-jitter technology that provides a full amplitude of anti-jitter without increasing noise floor
and other undesirable effects.

Based on this new generation of technology May “梅” can provide a SINAD of >115dB and a dynamic range
of >130dB, which represents the performance limit reached by today’s most advanced R2R architecture
DAC.

Using the ultimate performance of PLL+FIFO technology, provides 0.1Hz Third-Order low-pass ability to
inhibit jitter. It also uses a high-performance femtosecond VCXO as the PLL clock source. Under the premise
of being almost immune to the front-end jitter, it can also lock up to 1.5us-2us @ 1KHz signal with high
jitter. (It can lock up to 1.5us-2us @ 1kHz signal with high jitter on the premise of almost being immune
front-end jitter).

Dual Mono DAC L/R channels are independently powered by their own dedicated transformer in the PSU
chassis. This provides better channel separation and more accurate sound stage.

Official Support USB and I2S up to DSD1024 and PCM1.536MHz sample rate.

The USB interface uses proprietary firmware with ultra-low latency, a highly reliable data transmission, ideal
USB eye pattern measurements that contributes to 2-4 times higher performance than official firmware.

Two sets of independent HDMI-I2S input interfaces are provided, and each set of I2S has a four-way
independent circuit, as opposed to standard LVDS chip, making I2S clock signals subject to lower
interference and lower jitter. In addition, each group of I2S inputs can be configured with specific pinout
configuration, making it compatible with most of the HDMI-I2S digital devices on the market.

That’s mostly marketing. If you think you can make a good DAC with that information, you’re sorely mistaken. It’s about the people designing and implementing it. 
 

A DAC put together with what armchair engineers consider the best parts, won’t get one very far. It takes skill and experience to understand what’s not in the app notes. 
 

We’ve all seen it happen countless times, where someone believes a specific part should’ve been used in an audio component. They then mod the component with that part. However, they have zero understanding of why the part was used in the first place. If designers had to explain their part choices to everyone, they’d just go with whatever people thought was best, because that’s what would sell, rather than fight the crowd. 

[The Computer Audiophile]

Remember the THD+N wars? Turns out when people got that info, they though it mattered. Manufacturers sacrificed other parts of the design just to get lower THD+N. That’s what armchair engineers thought was important. Turns out, it wasn’t what they thought. 

[fas42]

I certainly find it intriguing how many are so deeply concerned about the technical aspects of how the music they consume reaches them, the steps that are taken to create the sausage, . Personally, the only thing that matters is whether the experience of listening to a recording, any recording, is full of positives; the absence of any negatives means that all the boxes are ticked. Which is why I have almost zero interest in OTT, ambitious rigs - if it doesn't deliver the goods that matter to me, then it's a dud.

 

In part I think that the differences in attitude are because there is a spectrum where at one end there are pure collectors, and at the other end the experience, the being in the now, is everything. Where one lies will determine how seriously one takes these sort of matters ...

[The Computer Audiophile]

34 minutes ago, hopkins said:

 

If we make the parallel with equipment, I am sure you would agree that many audiophiles take into consideration design aspects when choosing equipment. Many find it interesting to know what makes a product unique, what problems it's trying to solve, even if we know the proof is in the pudding. At the very least, we want to be reassured that we are getting the best "technology" available. "This sounds good" is never really good enough, many of us are curious to understand what's under the hood. It's rare nowadays for a manufacturer not to share technical information. Why would this be different with recordings (especially those geared towards "audiophiles") ? 

 

I have included at the bottom of this post the product description of the Holo May DAC (which I was recently reading), copied from their website: https://www.kitsunehifi.com/product/holo-audio-may-dac/.

 

You've got to be an armchair engineer to understand any of it! For the many of us who do not understand what all this means, it may still influence us and determine what we pay attention to.

 

They conclude by explaining:

 

 

 

 

So two questions:

- how would you feel if you found out that the technical description of one of the equipment you purchased was intentionally deceiving/false ?

- would you go as far as suggest that manufacturers don't publish this type of information so as not to influence our choices ?

 

--- May DAC description ---

 

Some noted features:

The May DAC (all three models) will also support DSD1024 native and PCM 1.536MHz output! Theoretically it can do DSD2048 and PCM 3.072Mhz however is untested at this time. Also, we have worked hard to reduce the common click noise with all dacs when switching from DSD to PCM. This sound click sound has been reduced significantly with a special circuit design. The May DAC has the new and exclusive USB Enhanced module (L2 and KTE ONLY) which has our FPGA with the new Titanis 2.0  and custom firmware to improve USB Eye Pattern and reduce latency to near zero as well as reduce jitter to very very low levels. The USB module has completely new code written to optimize performance and reduce latency significantly. Low frequency performance (-40db) is also improved. The “enhanced” USB xmos module is twice as powerful/capable as the one that is used in the Spring2.

New improved power supply circuit with high performance multi stage regulation circuit using Rubycon ZLH caps, Panasonic FC, Vishay Caps or L2/KTE models with our exclusive HoloAudio Branded Caps (KTE model unique custom proprietary caps to replace Vishay caps)

We are no longer using common LVDS chipset and are now using a custom 4way circuit that isolates each line which further improves sound quality. such as the MCLK is isolated from data line and this improves jitter spec. Also there are TWO i2s ports in the May dac. Each one can be individually configured pin outs to support all i2s products on the market.

The May and KTE version of the May DAC also is with a CNC machined aluminum remote control! Standard with all three models.

The KTE version has OCC copper wire replaced with 1.5mm pure silver wire. 1.5mm Silver wire is soldered direct to the pcbs with highest grade audio solder. Silver Rhodium Faston connectors used at IEC input.

The May is a DUAL mono DAC. so there is a dedicated Dac Module for Left Channel and a dedicated Dac Module for Right Channel. Also each channel is individually powered by it’s dedicated Otype FLATWIRE transformer found in all three models. We have found after careful testing this new transformer type outperforms ALL transformers we have ever tested to this date. Near zero leakage, improved dynamics and overall spectacular performance. They are handmade for this dac specifically and delivery world class performance you would expect.

May DAC also has a new screen on the front that appears the same as the Spring2 on initial glance…. Font size is bigger than Spring2 but smaller than Spring1. Also you can see the CD track-time information is displayed when using spdif inputs!!!. This is done by extracting additional data from SPDIF. This a part of CD red book standard but nobody notices this and often forgets this cool feature or doesn’t know how to extract the data!. This will lead a fashion for other DAC developer to support this feature… customers will surely love this feature albeit subtle. The screen is much better contrast and viewing angles and one of the first things one may notice.

The May also has a front power button now! It’s been a request by many customers and gone are the days of a good old reach around to get the dac to be turned on! As mentioned before above… The DAC has a soft start circuit!! So don’t fret, it takes a moment for it to charge up and pull power without blowing the fuse!! It actually uses the same exact value of fuse that our Spring1 and Spring2 has! But two transformers! If we don’t have a soft start a couple issues can happen… one being a blown fuse from power surge, and another simply having possible pop noises. No chance of these things happening. We have carefully designed the circuit to have a zero compromise design.

Technical Information about our Custom PLL circuit:-

Now the May is implemented with femto clocks, and also new discrete ultra high performance voltage regulators. It has an advanced PLL (phase lock loop) circuit that is completely custom built for ultra high performance anti jitter performance. Even the highest levels of jitter are near eliminated which delivers world class performance. Using Crystek VXCO clocks that will take any incoming digital signal an reclock it to perfection! This feature can be enabled or disabled to test and prove it’s performance is truly spectacular. Note: this is NOT an off the shelf PLL, but it’s truly the most powerful PLL found in a DAC. Or at least to our knowledge it’s the most powerful PLL ever.. Spdif usually is a not a good protocol because it’s very old and dated! It was designed in 70s together with CD with Sony and Philips. As you may know, It encodes the data signal together with clock signal so it can be transferred by a one-core cable. It makes the cable easy to source, but to encode the data to clock at the transmit side and decode the clock from data at the receiving side, creates jitter. Toslink is a fiber glass version of Spdif. So Toslink adds even more jitter while doing electronic to photo and photo to electronic translation. So people will see clearly that I2S is usually better than SPDIF because I2S has 4 separate signal, 3 clocks 1 data. So it does not have encoding-decoding stuff thus has a better jitter performance. This is important to know this.

A common technique to improve the clock signal from SPDIF is PLL. A PLL is to use a local clock generator to track the source clock. You know jitter is actually a time deviation problem. For example, the fist period frequency is 44101Hz and the following second period is 44099Hz. Thus it has 2/44100 jitter. A PLL is to smooth the time deviation of clock. So after the PLL, it can be 44100.9-44099.1(this is a weak/poor performing PLL). Or it can be 44100.1-44099.9(this is a strong performance PLL). Usually, a SPDIF chip, like AK4118A, has an internal PLL. AK4118A is good chip compared to other Spdif receiver chip and it marks 50ps jitter. It’s the best we can get from a commercial chip. But it’s far from ideal, and definitely not enough for a HiFi standard we are implementing in the May dac. So we need a significantly stronger performing PLL. If the PLL is strong enough, it can smooth the 44101-44009 source clock to 44100.00001-44009.99999(very close to ideal 44100-44100)

But to make a stronger PLL is not easy, it’s actually incredibly difficult. First you need a powerful local clock source. A fixed clock can’t be used because it need to be adjusted to follow source clock rate. A common solution to use a VCO(voltage controlled oscillator). VCO is made by resistors, capacitor and inductors. The cost is low but performance is not so great. So, a better solution is to use VCXO(Voltage controlled crystal oscillator), it uses crystal as oscillator and crystal is a far better oscillator. The VCXO we used in May is Crystek’s CVHD-957. This the best VCXO we can get now.

The second hard problem is, the data need to be synchronized with clock. For example, the source has 44101-44099 clock from Spdif, that also mean it has 44101 samples in first period and 44099 samples in second period. So a good local 44100-44100 clock will have to throw away one sample in first period and lack one sample in second period. An easy fix to it is to use digital filter to smooth the data and it calls ASRC, but ASRC actually modified the data. So after ASRC, the data is modified thus not bit perfect anymore. And digital filter can also generate time domain problems like ringing artifacts. So, a digital filter is not a good way to solve this problem, or you can say, it solve a problem by introduce another problem.

May uses a fifo buffer to store the extra one sample in first period and release it in second period. So it has no harm to data. The difficulty for this design is how to manage fifo buffer. It can be a problem when you have a long-term jitter. And long-term jitter is actually called low frequency phase noise in a frequency domain point of view. To explain it easily, let’s take a example, a long term jitter can be like this, 44101-44102-44103-44104-44105-44104-44103-44102-44101-44100-44099-44098-44097-44096-44095-44096-44097-44098-44099-44100. So you see, it will have 25 extra sample in first ten periods, so the fifo buffer need to able store enough of them and release it in next 10 periods.

So, as a result, May’s PLL’s corner frequency is set to 0.05-0.1Hz in 3-orders. Than means it can reduce a 10s long term jitter by 90%, 1s period jitter by 99%, 0.1s period jitter by 99.9%…… That maybe the most powerful PLL in this industrial. And the most important is, it won’t lose data, it can still locking the source while huge jitter comes in. When you compared other similar PLL in the industrial, you can see it simply unlock the signal when huge jitter comes in. So, in that way, it simply stop you from listening, it tells you there is a problem but not solve it.

I have attached 2 pictures. The AP equipment generate huge jitters to SPDIF(750ns, 1KHz). If the PLL turned off, you will see an very ugly spectrum that means the jitter distorted the analog signal badly. The other picture turn on the PLL, and you can see it beautifully removed almost all the jitters. Compared to other competitors PLL. They won’t remove the jitter so clean, and simply unlock the signal for more than 10ns jitters.

 

More about the May Dac.

The new generation of linear compensation technology solves the accuracy errors caused by resistor
tolerance, after compensation, reaching a variance of 0.00005% tolerance accuracy.

Proprietary anti-jitter technology that provides a full amplitude of anti-jitter without increasing noise floor
and other undesirable effects.

Based on this new generation of technology May “梅” can provide a SINAD of >115dB and a dynamic range
of >130dB, which represents the performance limit reached by today’s most advanced R2R architecture
DAC.

Using the ultimate performance of PLL+FIFO technology, provides 0.1Hz Third-Order low-pass ability to
inhibit jitter. It also uses a high-performance femtosecond VCXO as the PLL clock source. Under the premise
of being almost immune to the front-end jitter, it can also lock up to 1.5us-2us @ 1KHz signal with high
jitter. (It can lock up to 1.5us-2us @ 1kHz signal with high jitter on the premise of almost being immune
front-end jitter).

Dual Mono DAC L/R channels are independently powered by their own dedicated transformer in the PSU
chassis. This provides better channel separation and more accurate sound stage.

Official Support USB and I2S up to DSD1024 and PCM1.536MHz sample rate.

The USB interface uses proprietary firmware with ultra-low latency, a highly reliable data transmission, ideal
USB eye pattern measurements that contributes to 2-4 times higher performance than official firmware.

Two sets of independent HDMI-I2S input interfaces are provided, and each set of I2S has a four-way
independent circuit, as opposed to standard LVDS chip, making I2S clock signals subject to lower
interference and lower jitter. In addition, each group of I2S inputs can be configured with specific pinout
configuration, making it compatible with most of the HDMI-I2S digital devices on the market.

Question for you: Does this tell you anything about how the product sounds in your system?