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Discussion Starter #323 (Edited)
This ABX test also determines if the listener can audibly discern if the RCA wire I selected and the USB cable from the ADC back to the computer's hard drive used to record File B audibly compromise the sound. So far according to all posted results they don't. They seem to be perfect to the ear as well:

File B is: D ----->$7.99 D-to-A------------>analog RCA wire------------------------>A-to-D-------->USB cable back to my laptop's hard drive


The 6ft Monoprice 659 RCA wire is currently $1.05 [I bought them when on sale for 87 cents each]. It was brand new hence "not burned in".

The USB cable was free (it came with the ADC).

So if free USB cables and dirt cheap RCA cables sound perfect, why would we buy anything else?
[The RCA wire has a lifetime warranty by the way and with proper use they last for decades.]
 

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Discussion Starter #324 (Edited)
So if free USB cables and dirt cheap RCA cables sound perfect, why would we buy anything else?
Psst, the correct answer is "marketing".
 

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I believe you, I really do. Once the stay-at-home order is lifted I would really like to hear the Apple DAC at home, unfortunately I have a Pixel3, someone would have to bring over an iphone (anybody in Tucson?). I have a Tidal subscription, it would be real easy to temporarily install the Tidal app and listen to the same songs using both the iphone and my music server. I have no idea if there would be a difference, and any speculation would be just that, speculation. That's why we listen.



The USB cable was free (it came with the ADC).
So if free USB cables and dirt cheap RCA cables sound perfect, why would we buy anything else? [The RCA wire has a lifetime warranty by the way and with proper use they last for decades.]

ooh, ooh, ooh - tangents, I love tangents.


I use the JMaxwell USB, http://www.jmaxwellusb.com/ it is the best sounding USB for my system. I used the Schiit USB (rebranded Staightwire) for years and the JMaxwell is clearly better. Once, when I was troubleshooting my music server I switched USB cables, when everything was working again the music still didn't sound right, it was flat with attenuated bass, then I remembered the Schiit was still in the loop, after replacing the USB with the JMaxwell the magic was back. That was a totally blind test and I passed.

Our Tucson audio group compared the Danacable TruStream USB to a Nobility USB, Supra USB, Schiit USB (rebranded Straightwire USB-Link), and a Curious Cable. Three different systems yielded three different preferences: I preferred the Straightwire, Ben liked the Curious Cable in his system, and Ken thinks the TruStream USB sounded the best at his house. This happened a year before the JMaxwell made it's appearance.


Jitter and error correction? Don't know, I'm not an engineer.



Let the fun begin...
 

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Discussion Starter #327 (Edited)
ooh, ooh, ooh - tangents, I love tangents.
Actually I mentioned the RCA and USB cables aspect as an aside to the very first sentence of the very first post of this thread.
 

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Actually I mentioned the RCA and USB cables aspect as an aside to the very first sentence of the very first post of this thread.

Yup, we all need cables although the Jabra Elite 75t earbuds sound pretty good for bluetooth. I uses them for cardio, great to be wireless.

Have you plugged the iPhone and DAC combo into your stereo yet? Seems like all radio stations stream so you don't need Tidal or Qobuz for a test.
 

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I believe you, I really do. Once the stay-at-home order is lifted I would really like to hear the Apple DAC at home, unfortunately I have a Pixel3, someone would have to bring over an iphone (anybody in Tucson?). I have a Tidal subscription, it would be real easy to temporarily install the Tidal app and listen to the same songs using both the iphone and my music server. I have no idea if there would be a difference, and any speculation would be just that, speculation. That's why we listen.






ooh, ooh, ooh - tangents, I love tangents.


I use the JMaxwell USB, http://www.jmaxwellusb.com/ it is the best sounding USB for my system. I used the Schiit USB (rebranded Staightwire) for years and the JMaxwell is clearly better. Once, when I was troubleshooting my music server I switched USB cables, when everything was working again the music still didn't sound right, it was flat with attenuated bass, then I remembered the Schiit was still in the loop, after replacing the USB with the JMaxwell the magic was back. That was a totally blind test and I passed.

Our Tucson audio group compared the Danacable TruStream USB to a Nobility USB, Supra USB, Schiit USB (rebranded Straightwire USB-Link), and a Curious Cable. Three different systems yielded three different preferences: I preferred the Straightwire, Ben liked the Curious Cable in his system, and Ken thinks the TruStream USB sounded the best at his house. This happened a year before the JMaxwell made it's appearance.


Jitter and error correction? Don't know, I'm not an engineer.



Let the fun begin...
It's literally impossible for a cable carrying a digital signal to make a difference in the data transmitted unless it's so bad it's actually failing to send the data. There isn't an avenue going from botched bits to subtle degradations in sound, when bits break, it's dramatic. Plus, that wasn't a blind test, you changed the cable, even if you closed your eyes, you still knew which cable was in the loop.
 

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It's literally impossible for a cable carrying a digital signal to make a difference in the data transmitted unless it's so bad it's actually failing to send the data. There isn't an avenue going from botched bits to subtle degradations in sound, when bits break, it's dramatic. Plus, that wasn't a blind test, you changed the cable, even if you closed your eyes, you still knew which cable was in the loop.

Your statement does not advance the explanation of why USB cables sound different. More research is needed. Please read the entire paper in the link, cables are mentioned.

http://www.enjoythemusic.com/magazine/manufacture/0509/

Jitter in Digital Audio Data Streams
Article By Steve Nugent Of Empirical Audio

Steve Nugent, who is an Electrical Engineer with 25 years digital design experience in the computer industry designs all of our products. He has a broad experience in digital system and interface design, board layout, transmission-lines and other relevant technologies. Steve was a design-team lead on the Pentium II at Intel Corp. and holds 22 patents in various cable and digital technologies. Steve has had audio as a personal hobby for over 39 years.


"For instance, I use two oscillators that are both specified at 2psec RMS jitter. The two oscillators sound radically different to me when used in a re-clocker in a resolving audio system. This leads me to believe that the spectrum, or frequency content of the jitter is as important or maybe even more important than the amplitude. I also believe that correlated jitter or jitter with a relationship to the data pattern is also more audible than random jitter. This seems to be the consensus in a number of AES papers.
Studies by the AES (analysis, not human testing) conclude that these are the thresholds of audibility:
[1] 120psec P-P jitter audibility threshold for 16-bit DAC and 8psec P-P jitter audibility threshold for 20-bit DAC
[2] 20psec P-P of data-correlated jitter audibility threshold at certain frequencies and "A simple model of jitter error audibility has shown that white jitter noise of up to 180psec P-P can be tolerated in a DAC, but that even lower levels of sinusoidal jitter may be audible"


I guess I wasn't clear about my cable change. I completely forgot I switched cables while troubleshooting. All my wires are in a rats nest behind the electronics so there was no way to visually see what USB wire was hooked up. I made the discovery by listening alone.

 

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Your statement does not advance the explanation of why USB cables sound different. More research is needed. Please read the entire paper in the link, cables are mentioned.

http://www.enjoythemusic.com/magazine/manufacture/0509/

Jitter in Digital Audio Data Streams
Article By Steve Nugent Of Empirical Audio

Steve Nugent, who is an Electrical Engineer with 25 years digital design experience in the computer industry designs all of our products. He has a broad experience in digital system and interface design, board layout, transmission-lines and other relevant technologies. Steve was a design-team lead on the Pentium II at Intel Corp. and holds 22 patents in various cable and digital technologies. Steve has had audio as a personal hobby for over 39 years.


"For instance, I use two oscillators that are both specified at 2psec RMS jitter. The two oscillators sound radically different to me when used in a re-clocker in a resolving audio system. This leads me to believe that the spectrum, or frequency content of the jitter is as important or maybe even more important than the amplitude. I also believe that correlated jitter or jitter with a relationship to the data pattern is also more audible than random jitter. This seems to be the consensus in a number of AES papers.
Studies by the AES (analysis, not human testing) conclude that these are the thresholds of audibility:
[1] 120psec P-P jitter audibility threshold for 16-bit DAC and 8psec P-P jitter audibility threshold for 20-bit DAC
[2] 20psec P-P of data-correlated jitter audibility threshold at certain frequencies and "A simple model of jitter error audibility has shown that white jitter noise of up to 180psec P-P can be tolerated in a DAC, but that even lower levels of sinusoidal jitter may be audible"


I guess I wasn't clear about my cable change. I completely forgot I switched cables while troubleshooting. All my wires are in a rats nest behind the electronics so there was no way to visually see what USB wire was hooked up. I made the discovery by listening alone.

There is not a single mention of objective testing that demonstrates audibility of jitter. The only relevant bit in the article is this:


The live listening AB/X studies published to date (that I have read) are inconclusive IMO. The systems used were not resolving enough IMO, the recording quality was not good enough and the test signals were random and not correlated and therefore inadequate to properly test for jitter audibility.

The implication being that testing hasn't shown audibility so far. ABX testing may be 'contrived', just like double blind testing for drugs is very contrived, that doesn't detract from the fact that they are the gold standard by which these things get determined. His claim of the systems used weren't sufficiently 'resolving' is the tired claim made by folks who fail to hear the differences they are sure they can hear. Humans simply cannot be relied upon to make these determinations. It's an extremely well documented fact.



This guy seems like a dedicated talented professional, why doesn't he just demonstrate the audibility he claims to hear so clearly and reliably? Look at this thread, is he incapable of doing something analogous? All the IMO in the world isn't worth a single ABX test.
 

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Discussion Starter #332 (Edited)
Your statement does not advance the explanation of why USB cables sound different.
Tell us, do you similarly think hard drives sound different too? Although much smaller in length don't they have connection wires, circuit traces, and connection/junction points which exhibit "jitter" and all the other things the reviewers claim matter to the audible sound? Why would the 1mm length wires they use not have jitter but 1m ones do?

It may theoretically be true that USB cables sound different (not that I have ever seen scientifically controlled listening tests to support such a notion because none exist) but to verify this we would need to test every single one (so not happening). We do however now have evidence (according to my double blind, level matched, song synchronized test) that this quite ordinary free one (it came with the ADC I bought for $79.95) sounds perfect to every single party posting their test results so far.

So for all the people having trouble finding a perfect USB cable which introduces no audible degradation whatsoever and completely resolves every single detail in the music, you might consider buying this ADC and throwing it out but keeping this "special" USB cable it comes with. This would have a markedly lower cost that some of the USB wires mentioned earlier such as the $350 one.

Another thing you might consider is that the reviews claiming that audible differences exist don't have adequate protocols in place to exclude expectation bias from invalidating their test and they have not accounted for the fact that any two wires with ever so slightly different ground wire resistances will manifest different changes to ground loops due to the different potentials (electrical voltages) those differing resistances introduce.

People often have faint ground loops even when they aren't consciously aware that they do.
 

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Discussion Starter #333
Have you plugged the iPhone and DAC combo into your stereo yet?
Yes. I have owned it since 2014. It sounds like any other transparent DAC: perfect to the ear.
 

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So if free USB cables and dirt cheap RCA cables sound perfect, why would we buy anything else?[/I] [The RCA wire has a lifetime warranty by the way and with proper use they last for decades.]
Whoa, hold on there! You have that RCA cable all looped up. You've introduced a coil to the circuit, you animal!! :p

I would spend more money on RCA cables to get something thicker and more reliable, and that looks better. Not a LOT more, but more. There are valid reasons other than sound quality for spending more on an RCA cable than 87 cents lol. I won't fool myself into thinking the RCA cable somehow sounds better tho! ;)


It's literally impossible for a cable carrying a digital signal to make a difference in the data transmitted unless it's so bad it's actually failing to send the data. There isn't an avenue going from botched bits to subtle degradations in sound, when bits break, it's dramatic. Plus, that wasn't a blind test, you changed the cable, even if you closed your eyes, you still knew which cable was in the loop.
Ya I never understood the thinking on this one. Things that might affect analog are irrelevant with digital. It's a series of 1s and 0s. If the cable is so bad that it's dropping bits, the sound will be VERY different - it may not even be recognizable as music. If its not dropping bits I see no way possible for just the bass to somehow be attenuated or the frequency response to be affected in any way whatsoever. The only argument I have heard in favour of this is jitter, and I'm not aware of any tests that definitely prove it. I've seen lots of rhetoric but no proof. The only measurements I've seen of DACs where USB cables made a measurable difference were below -120 dB - completely inaudible. And this was with a poorly designed DAC.
 
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Discussion Starter #335
Not a real quote: "USB A sounds better than USB B and here is the proof: using sophisticated test gear with a clock stabilized to only .000001 femtosecond of residual jitter, USB A measures 74.61 whereas USB B is 86.27. Although that difference may not be audible to all people I have an EE degree, I'm a musician, and I have Reference Series, Dominator MX-10 speakers so I can hear it."

This is a common trick used by snake oil peddlers [Not to impugn this particular person mentioned earlier. I am just bringing up a new theoretical example]. What they do is show some measurement which differs, doesn't matter what it is really but the more obscure and non-measurable by the general public the better, and then they claim that's "proof" their claimed audible difference exists. They have actually provided no proof that's why they "hear" a difference nor that they've even heard one (under controlled conditions) in the first place. All they have proved is there is some measurable aspect which differs. There always is.

My free USB cable truly is 74.61, by the way (I measured it) and here's the scientific proof determined with precision, digital, professional grade gear:
 

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Tell us, do you similarly think hard drives sound different too?.

None that I have heard except when the OCZ SSD in my music server had a catastrophic failure a couple of months ago, then I heard nothing. I had a current image backup made with the free Paragon Backup and Recovery so restoring the OS and apps on a new SSD was quick and painless.

You may be onto something with the ground loops.

Good to hear the iPhone DAC works with a stereo, looking forward to playing with one.
 

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I have had digital audio playback issues, both network and local and there are no "the bass was flat" or "less detail" problem conditions. When digital audio transport goes bad it's one of these:

  • No sound at all
  • Gaps, pauses, stuttering
  • Horrible squelching noises that sound like they might damage your speakers
A bad cable or crappy wifi can cause the first two, the third is typically a source file getting corrupted or a software layer issue like a bad stream.
 

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Discussion Starter #338 (Edited)
Good to hear the iPhone DAC works with a stereo, looking forward to playing with one.
It works fine into a stereo however its voltage level may be a bit low even at the iOS device's max volume compared to most standalone DACs meant to be connected to stereos so you would find it is quieter. This makes casual A/B comparisons problematic since you need a serious tweak of your volume knob at each switchover. [Some audio devices, including many upscale AVRs from Denon and Yamaha, allow you to set the input level sensitivity per input. That would be a useful feature for this sort of situation.]

Serious evaluations must be at exactly the same level as determined by instrumentation. Not doing this is probably the number one mistake of hobbyists (and some "scientists" too).
 
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Discussion Starter #339 (Edited)
Digital almost always either works perfectly or has serious hiccups/sputters/ or the signal goes completely dead.

I have an interesting test CD with progressively worsening dropouts made to simulate larger and larger surface defects and data loss. The transition between "This sounds perfect" to "This has major distortion and severe glitches/hiccups" is very abrupt.

You can actually see the progressively larger dropouts with the naked eye:


CDs play from the center of the disc outward, for any of you who may not know that.
 

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None that I have heard except when the OCZ SSD in my music server had a catastrophic failure a couple of months ago, then I heard nothing.
LMAO! I had a good chuckle at this one. I guess SSDs CAN affect sound quality :D
 
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