MQA is Vaporware

[Indydan]

58 minutes ago, Charles Hansen said:

 

It's an interesting idea. And pretty much every cable company has their philosophy they espouse. The vast majority of them make some sort of sense, in at least a "hand-waving" way. However the linked video seemed to imply the "DTCD" was far and away the single most important parameter.

 

That always sets off alarm bells for me. I have "designed" some cables that Cardas made to Ayre's specifications, and my experience is somewhat different in that I find many, many factors will affect the "sound" of a cable.

 

One of my biggest gripes with cable companies is that they are almost universally designed to sound "impressive" and "spectacular" in a quick 5 minute back-and-forth demo at your dealer. This simply does not work for me. For example with power conditioners, I have found that the only reliable test is to put into your system for at least 3 weeks. This allows it to fully break in and for you to become accustomed to the sound.

 

It's only when you REMOVE the PLC that you can get a clear picture of how it helps and how it harms.

 

The other ridiculous thing is the pricing. I find it extremely hard to believe that any pari of speaker cables is worth as much as a pair of our top=-line monoblock amps. I've built some prototypes of interconnects and speaker cables tat would retail for between $300 and $500 that are simply the best sounding cables I've every used. (And no, I don't think they would do especially well on the DTCD test.

 

Cheers!

 

PS - Full disclosure - I've never tried any Shunyata cables. It is possible that they would become my new favorites. But my experience has always been the opposite - when I listen to the latest "must-have" cables, I am always left unimpressed overall. There will be certain aspects of their performance whereby I can understand how someone would be impressed, but I could never live with them long term.

 

Thanks for providing your opinion! I do agree that some cables are ridiculously expensive. The Nordost Odin series and Siltech's top cables are more expensive than some very good complete systems. I don't have any of those cables! 

[mansr]

52 minutes ago, psjug said:

So the crappy power cord only allows a burst of 500 amps?  How much does your amplifier's transformer want?

A power supply drawing such spikes is flawed. What does he think those huge capacitors are for?

[Indydan]

59 minutes ago, Charles Hansen said:

 

You mean he's not like me?

 

Well, I don't know if I would call you angry. You aren't shy about expressing your opinions. There is nothing wrong with that. Your point of view does come from experience and success in the audio business. 

 

But, most of the time, a person doesn't really know who they are talking to on the Internet. 

[mansr]

1 hour ago, Charles Hansen said:

And pretty much every cable company has their philosophy they espouse.

Quite often contradictory ones. They can't all be right.

[Indydan]

1 hour ago, psjug said:

So the crappy power cord only allows a burst of 500 amps?  How much does your amplifier's transformer want?

 

It is instantaneous current that is important. The theory is explained in another video I believe. The more current that an amplifier or source can get in one shot, the faster the capacitors fill up. The power supply emits noise when the amplifier is taking in current. The more instantaneous current, the faster the capacitors fill up and the power supply emits noise for a shorter duration. 

 

Here is the explanation from Caelin Gabriel from the WBF:

 

 

Some of you have basic misunderstandings about AC power delivery and power rectification specifically. Without some basic knowledge you will never understand the subject.

It is necessary to understand the manner in which power supplies in consumer electronics function. The integrated circuits in consumer electronics require several DC voltages to operate. It is the job of the power supply to convert alternating current (AC) from the wall outlet to direct current (DC) voltages that supply power to the component's electronic circuits.There are basically two types of power supplies: transformer and transformer-less (switched mode) power supplies. Both use rectifiers that are essentially electronic switches that alternately turn on and off in response to the input AC voltage. It is the rectifiers that convert the AC voltage to a pulsating DC voltage.. This voltage is stored and filtered by the power supply storage capacitors that provide the relatively stable DC voltages to the PCBs and integrated circuits.Unlike a light bulb, fan or simple motor, audio/video power supplies do not pull current in a constant or linear fashion. Rather, they pull current in instantaneous pulses as the rectifiers switch on to fill the storage capacitors. This is as true for low current devices such as CD players and pre-amplifiers as it is for high current amplifiers. The rectifiers turn on and off at the positive and negative voltage peaks of the AC waveform. These current pulses have high frequency harmonics up to 50 times the frequency of the AC power line. This places a great demand upon the AC power circuit and associated connections to deliver current without significant impedance to the flow.

Placing anything in front of an electronics system that restricts, impedes or slows instantaneous impulse AC power will often noticeably degrade the performance of the system. This is why most electronics manufacturers discourage the use of power conditioners. They understand that traditional low-pass power “conditioners" interfere with instantaneous current flow and interfere with the performance of their carefully engineered power-supplies.

How do you measure current pulses?

Conventional AC power testing methods and equipment are not designed to detect the volume of current delivered during the brief conduction period (milliseconds) and the corresponding impedance during the period of conduction. Multimeters measure voltage and current averaged over a period of one or more AC cycles. Common current probes are too slow to give an accurate reading of current delivery during a single current pulse that has a period of only a few milliseconds.

What is DTCD - dynamic transient current delivery?

DTCD is method of current analysis that measures instantaneous current delivery in the context of a pulsed current draw. In layman’s terms, it is a way of measuring current performance into typical electronic component power supplies. It allows the measurement of pulsed transient current through a variety of AC power products, including: power wiring, outlets, distribution panels, terminals, connectors, power cords and portable power distribution boxes. 

Shunyata Research developed a DTCD ANALYZER specifically designed to perform DTCD measurements. The analyzer simulates the pulsed current draw of typical electronic power supplies. It supplies a precision reference voltage to the DUT (device under test) and measures its ability to conduct current during a short gate time (milliseconds). The DTCD ANALYZER provides a read-out of the equivalent current (DTCD-I) that the DUT could deliver in a one second time period. It also calculates the equivalent voltage drop (DTCD-Vd) and corresponding impedance (DTCD-Ƶ).

And to save you some time here are some of the most common misconceptions about DTCD graphs.

Why is the amperage in the graphs so high?

You may be thinking that your CD player only pulls about one amp of current and your amplifier only draws about 12 amps. So how can a test be valid that shows the cord pulling hundreds of amps of current?

Power supplies only pull current for about 5% to 10% (or less) of the AC duty cycle. During the conduction period, when the cable is actually conducting current, the instantaneous current could be hundreds of amps, but the longer term average is only one to 20 amps, depending upon the device and the load.

Note: If a power supply is drawing 10 amps of current (as measured by a standard current meter), then the peak currents would be 10 to 20 times higher or 100-200 amps of instantaneous current.

—

It appears from the graph that the standard power cord has voltage drop of more than 50%. How is this possible?

The answer is similar to the answer above. Since the conduction period is short and fast, the cable is presented with an instantaneous change in current. The impedance and inductance of the cable resists the change in current and causes a short term voltage drop across the cable. Of course, there is not a sustained or significant average voltage drop. Otherwise, the equipment wouldn't function.

The DTCD Analyzer uses a source voltage of 30 volts to represent a typical difference voltage between the power supplies storage capacitors and the peak voltage of the line. So, the graph is indicating the amount of voltage drop between the voltage on the capacitors and the line voltage - not the difference between the peak line voltage and ground.

Note the peak of the standard power line(120 volts AC) is about 163 volts (Peak) depending and what the crest factor (1.35 typical) of the power line. What the test shows is that the standard power cable under these test conditions would have a 15 volt drop in the power cable while sourcing 130 amps. While the Venom-3 power cable would only have a 5 volt drop and have the ability to provide almost twice the current 230 amps. – at a third of the cable voltage drop. 

Note again that the conduction period is 1/10 to 1/20 of the power line cycle, so peak currents are 10 to 20 times higher than measured RMS currents or rated currents. A power amp at full power can be drawing 10 amps, resulting in peak current draw during the charging period of 100 to 200 amps. If the power amp needs 130 amps of current during the peak charging period, the standard power cable would have a cable voltage drop of 15 volts. This would limit the ability of the input stage of the power amp to fully charge, which effectively would create a relative low line condition as the input stage of the power amp will not be able to fully charge. To put it another way, the input line voltage has been reduced from 120VAC to about 110VAC!

—

Microseconds seems like an unreasonably short period of time to measure current. Why is that?

Since power supplies pull current in pulses and the pulse duration is typically less than 10% of the duty cycle, the conduction period is typically 200-800 microseconds. The time scale for the graphs is about 50 microseconds from beginning to end. Notice that the slope of the measured waveforms levels out and stabilizes within that 50 microsecond timeframe. Therefore, it is unnecessary to display information beyond the 50 microseconds. In other words, the measured differences would be the same even if we extended the time period beyond that shown.

—

If the standard power cord slows current delivery, doesn't it just take a bit longer to fill the storage capacitors?

This is true and explains why the power supply will function within normal average voltage and current requirements. However, that does not mean that there are not audible differences between a cord with better DTCD. A cord with higher instantaneous current delivery will fill the storage capacitors faster. Therefore, the rectifiers are on for a shorter period of time. The longer it takes to fill the storage capacitors means that the peak of the charging waveform has passed while still trying to charge the storage capacitors, thus not able to fully charge the storage capacitors. Also, note the volt drop in the power cable limits the ultimate voltage level that the filter capacitors can be charged to. 

A power cable able to supply 300 to 400 amps of charging current will have a much shorter charging time than a cable only able to supply 100 amps. The 100 amp power cable will have voltage drops and resistance that limits its ability to fully charge the input capacitors. As the charging will not be finished before the peak of the power line charging cycle has passed. 

This reduces the amount of time that the power supply is in a low impedance, open condition to the power line. When the rectifiers are on, power line noise is more likely to be transmitted through to the power supply.

http://www.whatsbestforum.com/showthread.php?16172-DTCD-Explained

 

[Miska]

16 minutes ago, mansr said:

In the B&W 600 series the aluminium dome resonance is at roughly 25 kHz. In the more expensive CM series, still aluminium, it is at 35 kHz or so. Can't say I can hear any difference from this.

 

Maybe you don't use as leaky filters to put much energy there, although it doesn't necessarily need input at that frequency to trigger it...

 

In any case, the main point was that it is good indication of material properties of the tweeter...

 

[mansr]

1 hour ago, Charles Hansen said:

The other ridiculous thing is the pricing.

The absurd magnitudes aside, I find it strange that whatever the purported "scientific" principles, all these companies manage to offer a range of "performance" levels with neatly staggered prices. And every few years, they miraculously conjure up an even "better," even more expensive model. It is clear to me that they are playing directly into typical audiophile's obsessive upgrade chase. The only "science" involved is psychology.

[Miska]

I like (and use) Supra cables, not much B$, and the price isn't too bad. And they conform with my view on how cable properties should be, and publish the relevant specifications...

 

http://www.jenving.com

 

[psjug]

Sorry, I can't take the time to do better right now, but my point was I don't believe your system will ask you to pull  500A through your amplifier's primary winding, and I doubt it is possible for that much current to flow in the primary winding's path anyway.  Maybe I'm wrong.

[mansr]

25 minutes ago, Indydan said:

Shunyata Research developed a DTCD ANALYZER specifically designed to perform DTCD measurements.

Any product that can only be justified through the invention of new terms (and measurement devices) sets off my warning bells. That's something MQA and Shunyata have in common.

[Charles Hansen]

59 minutes ago, Indydan said:

It is the job of the power supply to convert alternating current (AC) from the wall outlet to direct current (DC) voltages that supply power to the component's electronic circuits.There are basically two types of power supplies: transformer and transformer-less (switched mode) power supplies.

 

This is just plain wrong. All switch mode power supplies have transformers to isolate the equipment from the AC mains. It is just smaller, cheaper, and lighter because it operates at a much higher frequency (often between 100kHz and 200kHz with modern MOSFET switching devices) than the typical AC mains of 50/60Hz. This is why aircraft have used 400Hz power for nearly a century - the higher operating frequency allows for smaller, lighter transformers - which is obviously critical for trying to increase the payload capacity of an aircraft.

 

Another "advantage" of switch-mode power supplies is that if there is any mechanical vibration that would normally be heard as a buzz or hum, it will be inaudible - except possibly to bats. The disadvantage is that you are putting a high powered RFI/EMI generator right inside the same box as your sensitive circuitry.

[Sal1950]

2 hours ago, mansr said:

They can't all be right.

Sure they can, they've all learned how to make a ton of money marketing absurd malarkey to a gullible customer base.

Audiophools and their money are soon parted.  LOL

[Rt66indierock]

It’s time to get this thread back on track. The LV30 smartphone will not play Tidal MQA tracks even though it has an MQA decoder in the DAC chip. Apparently you need to have the Oreo operating system installed and Tidal has to release a mobile application allowing MQA to be streamed. The current operating system Nougat will not work and it is unclear when the operating system of the V30 will be updated.  Tidal’s customer support has been unresponsive to those that have asked about the problem.

 

Since nobody seems to have noticed except for a few guys on head-fi we can assume two things there aren’t many LGV30 smartphones in the public’s hands and nobody cares about streaming MQA.

[rickca]

5 hours ago, Charles Hansen said:

I've built some prototypes of interconnects and speaker cables tat would retail for between $300 and $500 that are simply the best sounding cables I've every used.

I currently use much more expensive Ayre speaker cables and interconnects.  I'd love to try your latest prototype to compare.

[Don Hills]

57 minutes ago, Rt66indierock said:

It’s time to get this thread back on track. The LV30 smartphone will not play Tidal MQA tracks even though it has an MQA decoder in the DAC chip. ...

 

Do you know if it's a decoder or just a renderer - will require a core decoder in the app? (I suspect renderer only.)

[Charles Hansen]

3 hours ago, Rt66indierock said:

It’s time to get this thread back on track. The LV30 smartphone will not play Tidal MQA tracks even though it has an MQA decoder in the DAC chip. Apparently you need to have the Oreo operating system installed and Tidal has to release a mobile application allowing MQA to be streamed. The current operating system Nougat will not work and it is unclear when the operating system of the V30 will be updated.  Tidal’s customer support has been unresponsive to those that have asked about the problem.

 

Since nobody seems to have noticed except for a few guys on head-fi we can assume two things there aren’t many LGV30 smartphones in the public’s hands and nobody cares about streaming MQA.

 

Wow, what a fiasco! I'm sure those guys on Head-Fi bought the phone specifically to stream Tidal MQA files on-the-go. They must not be very happy after spending big bucks for the new LG flagship phone...

 

I'd bet right about now that the LG guys are regretting ever listening to Bob Stuart. It doesn't sound like this problem will be resolved for at least 6 to 12 months.

 

I was trying to figure out how many people subscribe to the Hi-Fi tier of Tidal. When they first came to the US, there were only 17,000 Hi-Fi subscribers in Europe. But I've read than almost half of the US market springs for the twice-as-expensive Hi-Fi service. It seems that Tidal is likely making most of its money from the US market. Maybe Jay Z. means something to the average consumer here. I sure wish Qobuz would enter the US market.

[firedog]

5 hours ago, Rt66indierock said:

It’s time to get this thread back on track. The LV30 smartphone will not play Tidal MQA tracks even though it has an MQA decoder in the DAC chip. Apparently you need to have the Oreo operating system installed and Tidal has to release a mobile application allowing MQA to be streamed. The current operating system Nougat will not work and it is unclear when the operating system of the V30 will be updated.  Tidal’s customer support has been unresponsive to those that have asked about the problem.

 

Since nobody seems to have noticed except for a few guys on head-fi we can assume two things there aren’t many LGV30 smartphones in the public’s hands and nobody cares about streaming MQA.

Shocking, just shocking!....

Where’s the witchdoctor to set us right?

 

[firedog]

2 hours ago, Charles Hansen said:

 

Wow, what a fiasco! I'm sure those guys on Head-Fi bought the phone specifically to stream Tidal MQA files on-the-go. They must not be very happy after spending big bucks for the new LG flagship phone...

 

I'd bet right about now that the LG guys are regretting ever listening to Bob Stuart. It doesn't sound like this problem will be resolved for at least 6 to 12 months.

 

I was trying to figure out how many people subscribe to the Hi-Fi tier of Tidal. When they first came to the US, there were only 17,000 Hi-Fi subscribers in Europe. But I've read than almost half of the US market springs for the twice-as-expensive Hi-Fi service. It seems that Tidal is likely making most of its money from the US market. Maybe Jay Z. means something to the average consumer here. I sure wish Qobuz would enter the US market.

A while back I saw a published estimate of 3 million subscribers, of which about a quarter were in the hi-fi tier. But other estimates say the total is more like one million.

[PeterSt]

2 hours ago, Charles Hansen said:

When they first came to the US, there were only 17,000 Hi-Fi subscribers in Europe.

 

Hi Charles - I'd rather call that "Norway" and under the name of Wimp Hi-Fi.. At the same time Wimp was rolled out in the US and its name changed to Tidal, it was rolled out in other countries. But for example not Netherlands yet. So it was just starting out nicely ... and then sold.

[esldude]

1 hour ago, firedog said:

Shocking, just shocking!....

Where’s the witchdoctor to set us right?

 

Well ultimately WD would have us put 13 channel Atmos upconverting chips in the phones and then do some VooDoo DSP to create that over earbuds.  Anything else is antique.  Dinosaur-like.  Discarded as a failed branch of audio evolution.  We're all doomed!

 

On the brite side, I guess that makes Atmos immersive audio and MQA like twin meteors that impact the audio earth with devastating consequences from which phoenix like modern audiophiles will evolve and populate the previously scorched earth.  

[PeterSt]

I can't find 14.8 MQA anywhere ?

[rickca]

1 hour ago, firedog said:

Where’s the witchdoctor to set us right?

I think he is immersed in the MQA Kool-Aid.

 

One of these days, someone should write a book about this whole MQA thing.  I don't mean something technical, more like a business book or a Tom Wolfe novel.

[mcgillroy]

45 minutes ago, rickca said:

I think he is immersed in the MQA Kool-Aid.

 

One of these days, someone should write a book about this whole MQA thing.  I don't mean something technical, more like a business book or a Tom Wolfe novel.

This episode certainly would make for a nice case-study in marketing. Wether if its how-to or how-not-to remains to be seen.

 

Personally I think they made every mistake in the book and basically invited criticism of the highest order into their front-yard.

 

Can you think of any other audio-"innovation" in the last 40 years that racked up a similar impressive list of reputable engineers and pros voicing concern and scepticism?

 

MQA - and the audiophile press - evidently misread and underestimated their audience. If they just had come out and said "this is DRM-light you can live with, is good for the artists ( = labels) + the format saves bandwidth and sometimes sounds better" they'd saved themselves a lot of trouble and probably had gotten more traction.

 

But at least It's all very entertaining and very educative

[Nikhil]

15 minutes ago, mcgillroy said:

MQA - and the audiophile press - evidently misread and underestimated their audience. If they just had come out and said "this is DRM-light you can live with, is good for the artists ( = labels) + the format saves bandwidth and sometimes sounds better" they'd saved themselves a lot of trouble and probably had gotten more traction.

 

 

+1  

 

I also don't know how they missed seeing the much bigger potential of the cell phone market.    For all the effort they have poured into pitching MQA to the audio industry, the cell phone / mobile industry would have dropped a couple of milllion dollars without thinking much of it.   This is completely their environment.  Another badge on the feature list to show something new - right next to the MP3 logo.     

 

 

[audiventory]

2 minutes ago, Nikhil said:

I also don't know how they missed seeing the much bigger potential of the cell phone market. 

 

Exactly. I think, radio channel is the best place of application for compressed formats.