[Guidostrunk]

I almost fell off my chair when I saw the price. Lol. I can't see how there would be some monumental improvement over something around 1k. It seems crazy for around 5k , that you get spaghetti, and meatballs, in a tin box.

GTFO!

Damn...you would think for that money they could invest in some better PCBs and a pick-and-place machine.

 

[Mortalcoil]

I almost fell off my chair when I saw the price. Lol. I can't see how there would be some monumental improvement over something around 1k. It seems crazy for around 5k , that you get spaghetti, and meatballs, in a tin box.  

 
The bread board is where alot of the cost is associated.

 

[watchnerd]

I almost fell off my chair when I saw the price. Lol. I can't see how there would be some monumental improvement over something around 1k. It seems crazy for around 5k , that you get spaghetti, and meatballs, in a tin box.

 
I've made homebrew DIY stuff with point-to-point wiring that didn't look as sloppy as that.

 

[watchnerd]

   
The bread board is where alot of the cost is associated.

 
I love how the tube is just lying off to the side, randomly, with a socket just dangling in free air.

 

[Mortalcoil]

   
I love how the tube is just lying off to the side, randomly, with no socket.

 
 
It allows the tube to suspend itself in mid air all the while ignoring the magnetic pull of the earths core.
 
Works great in earthquake zones as well.

 

[Guidostrunk]

Hahahahahahahaha , that's hilarious!

It allows the tube to suspend itself in mid air all the while ignoring the magnetic pull of the earths core.

Works great in earthquake zones as well.

 

[watchnerd]

   
 
It allows the tube to suspend itself in mid air all the while ignoring the magnetic pull of the earths core.
 
Works great in earthquake zones as well.

 
Any filaments that get busted are just making the circuit more straight wire.

 

[Mortalcoil]

 
Any filaments that get busted are just making the circuit more straight wire.

 
 
Exactly   

 

[mmerrill99]

I believe you are grossly exaggerating in the bolded text - according to what Stoddard wrote, this was not the case. But continue on, regardless!

Believe what you want. I read that whole thing as "an alarm went off and we investigated further." A yellow alert, if you will. But yes, obviously you think this is the start of a revolution and I'm like "meh", so we clearly see things differently.

Nah, I don't see it as any kind of revolution - multitone tests are old hat & have been used in telecomms days of yore - just not so much today

My point in raising it was I made this post "There are alway differences in the final waveform - the question is what type of test signal you use, what type of waveform analysis you do & what you consider below the threshold of audibility when dealing with complex waveforms!"

To which cjl replied "There are some things that are pretty clearly always below the threshold of audibility........"

And I gave examples that depended on the test signals used & the tests run as to whether it's pretty clear or not - the Schiit multitone measurement & Scott Wurcer's examples being a cases in point -IMD analysis showed little (Schiit) or no (Wurcer) sign of a problem & yet multitone analysis showed up many distortions. Simple enough to understand, really!

 

[charleski]

You are seriously going to cite that as a DBT test of worth? Come again!

 
While there is some merit to the quibble that they should have used pairwise presentations rather than trying to test all four DACs, and it's not certain that the assistant was properly blinded, their methodology is generally sound. It certainly carries far more weight than the sighted anecdotal reports that clog up audio websites.
 
I'd certainly like to believe that I personally could tell the difference between a well-engineered DAC and a cheap ALC889 codec chip, especially given that it was far from flat and over a decibel up at 100Hz. But I have to accept that I might be fooling myself.
 

Semantics - I was waiting for this! IMD = multitone, yea right!!
Of course it makes it harder to do & it also stresses the device in ways that a two tone test doesn't but continue on, regardless.
Yes you will find multitone tests on many analysers but how many manufacturers of audio DACs post multitone test results in their datasheets?
We see them in the datasheets of industrial DACs with SFDR (spurious free dynamic range) results but few audio DACs

Seriously? You think that a DAC gets 'stressed' by playing signals at more than two frequencies?? I really think you need to go back and think about that for a while, if only to spare yourself further embarassment. Both the DAC chip and associated output hardware are operating over the full audible range all the time - they don't get tired and give up if asked to reproduce both a flute and a cello. There's nothing special about using multiple tones to check for IMD. It's more efficient at covering the frequency spectrum and would obviate the need for multiple tests covering different ranges, but, as I said, it makes analysis of the results somewhat more difficult.
 
SFDR is cited for devices used in communication systems because it's a measure of the device's immunity to interference from other signals. This shouldn't be an issue for a home-audio system in which only one signal is present. Since the distortion products found in home-audio are spread across the audible spectrum the total value is generally a more useful measurement than the largest peak.

 

[mmerrill99]

While there is some merit to the quibble that they should have used pairwise presentations rather than trying to test all four DACs, and it's not certain that the assistant was properly blinded, their methodology is generally sound. It certainly carries far more weight than the sighted anecdotal reports that clog up audio websites.

I'd certainly like to believe that I personally could tell the difference between a well-engineered DAC and a cheap ALC889 codec chip, especially given that it was far from flat and over a decibel up at 100Hz. But I have to accept that I might be fooling myself.

Of course the other possibility is that the test is so ***** in every respect that it hides such an obvious difference!

Semantics - I was waiting for this! IMD = multitone, yea right!!

Of course it makes it harder to do

Seriously? You think that a DAC gets 'stressed' by playing signals at more than two frequencies?? I really think you need to go back and think about that for a while, if only to spare yourself further embarassment. Both the DAC chip and associated output hardware are operating over the full audible range all the time - they don't get tired and give up if asked to reproduce both a flute and a cello.

You know what IMD stands for, don't you? I wonder where those sideband distortions might be coming from?

There's nothing special about using multiple tones to check for IMD. It's more efficient at covering the frequency spectrum and would obviate the need for multiple tests covering different ranges, but, as I said, it makes analysis of the results somewhat more difficult.

Ah, yes difficult analysis - let's not do it then

SFDR is cited for devices used in communication systems because it's a measure of the device's immunity to interference from other signals. This shouldn't be an issue for a home-audio system in which only one signal is present. Since the distortion products found in home-audio are spread across the audible spectrum the total value is generally a more useful measurement than the largest peak.

You just chased your own tail in a logic circle blur - "This shouldn't be an issue for a home-audio system in which only one signal is present." - do you read back what you write - it's advisable ?

 

[watchnerd]

I'm sorry, but what are we debating again?
 
It seems like Schiit measured somebody else's "SuperDAC", that it had unexpectedly bad IMD in the lower range, and that it also did poorly on a multi-tone test.
 
Seems perfectly logical.
 
The only real mystery to me is how the "SuperDAC" got out the door with such crappy lower range IMD.

 

[mmerrill99]

I'm sorry, but what are we debating again?

Well, at the moment it seems cjl is struggling to understand IMD !

It seems like Schiit measured somebody else's "SuperDAC", that it had unexpectedly bad IMD in the lower range, and that it also did poorly on a multi-tone test.

Seems perfectly logical.

The only real mystery to me is how the "SuperDAC" got out the door with such crappy lower range IMD.

Well,
Same way as the DAC manufacturer's evaluation boards did - no noticeable IMD issues with standard tests. Only when tested by Scott Wurcer using Mutitone tests did substantial differences show up between the boards - enough for him to state "The multitone really separates the sheep from the goats. I'm using 30 1/3 octave tones at about 12db crest factor. Artifacts show up on even the best boards."

That's how tests are designed - use an optimal signal which will clearly reveal a specific issue being tested for. The jitter test signal is an example - it was not just a randomly chosen set of digital codes - it was using chosen digital codes (signals) designed to exercise the identified issues of inter symbol interference (ISI) that was identified with SPDIF receivers - it is specifically designed to maximally stress this aspect of SPDIF receivers. Of course now it is used as a general test for jitter & has lost it's original optimal design purpose but there you go.

 

[cjl]

Well, at the moment it seems cjl is struggling to understand IMD !

Oh, that's rich. I understand IMD perfectly. You do understand that the multitone test is still an IMD test, right? It's arguably a better IMD test than the standard one, and I'm always a fan of increased testing and data on all devices. That doesn't change the fact that all audible defects will be measurable though.

 

[watchnerd]

  Oh, that's rich. I understand IMD perfectly. You do understand that the multitone test is still an IMD test, right? It's arguably a better IMD test than the standard one, and I'm always a fan of increased testing and data on all devices. That doesn't change the fact that all audible defects will be measurable though.

 
Summary:
 
1. Schiit did 2 different types of IMD tests on a competing DAC.  They were surprisingly crappy in portions of the spectrum, enough to probably be audible.
 
2. Crappy IMD measurements that cross the threshold of audibility might correlate with subjective sound preferences.
 
That's it, right?
 
Seems pretty 'Well, duh' to me.