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USB cable and Sound Quality - Page 21  

post #301 of 783
Quote:
Originally Posted by Typhoon859 View Post

It gets its power independently.  In this comparison a USB/power cable was not involved.  It was just an example for the purposes of making a point against that one amp vs. another doesn't make a difference in most cases in quality for low impedance headphones/speakers.  I mentioned a simple case where it clearly did.  I thought just giving that example would be enough but obviously I was mistaken.  I just thought it was a shared understanding that a dedicated amp such as the one mentioned vs. any portable players of the likes results in noticeable improvement.  I've been convinced to the point that this may not be true but it remains to be seen.  I will do blind testing for it.

 

I think Amps make a difference. Probably not as much as the headphones themselves, but they do IMO. Cables? Probably less so.

 

To compare cables, I would definitively keep everything else the same for comparison purposes, and I would make sure that sufficient power is available. I think power loss through the cable shouldn't be an issue if the source has sufficient headroom to cover it along with the Amp needs.


Edited by ultrabike - 8/22/12 at 5:39pm

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post #302 of 783

E11 is just a $60 portable amp, no DAC.

 

When there is enough volume, you're more likely to find differences between amps by listening when using lower impedance headphones, not higher.

 

DACs getting power through USB is different than amps getting power.  Amps just draw as much power from the source as they use, where power consumed comes in the form of losses throughout the electronics as well as power delivered to the headphones.  I think there's some handshaking involved between USB host and slave between what power draw is acceptable.  There are some proprietary charging mechanisms using USB plugs.  I think some phones may not charge from some devices that don't actually communicate over the data lines—others are fine with a device that's just giving it the +5V and ground.  I'm not sure if any are sensing the USB +5V level.  If you have a USB cable that is (non-defective) but relatively long and thin, maybe you'll get enough of a voltage drop across the line to mess some devices up, especially combined with a host device that's drooping on the +5V level?  That sounds a bit farfetched but not impossible.

post #303 of 783
Quote:
Originally Posted by mikeaj View Post

E11 is just a $60 portable amp, no DAC.

 

When there is enough volume, you're more likely to find differences between amps by listening when using lower impedance headphones, not higher.

 

DACs getting power through USB is different than amps getting power.  Amps just draw as much power from the source as they use, where power consumed comes in the form of losses throughout the electronics as well as power delivered to the headphones.  I think there's some handshaking involved between USB host and slave between what power draw is acceptable.  There are some proprietary charging mechanisms using USB plugs.  I think some phones may not charge from some devices that don't actually communicate over the data lines—others are fine with a device that's just giving it the +5V and ground.  I'm not sure if any are sensing the USB +5V level.  If you have a USB cable that is (non-defective) but relatively long and thin, maybe you'll get enough of a voltage drop across the line to mess some devices up, especially combined with a host device that's drooping on the +5V level?  That sounds a bit farfetched but not impossible.


It does sound farfetched.  It's what I was thinking but also why I didn't mention it. 

 

In regards to the whole DAC vs. Amp thing.  Again, simply based on the understanding of their functions, I assumed the same.  As I said in my very first post, with USB as the source, some indicated elsewhere that the FiiO E17 (which has a battery) is dependent on the power from the USB regardless (which is confusing since it has an S/PDIF input as well).  But in any case, that's why I resorted to using the FiiO E10 as an example just for the sake of getting to the bottom of this in general, before it gets more specific. 

 

In any case, what do you say to my previous response?  What would you think of the results I'd come back with after having done a proper blind test.  Keep in mind that the unbiased result is just as important to me if not more so.  In other words, would this test on my part be sufficient enough for you?  The point would be for all amps alike, not just some possible flaw with the iPad's.


Edited by Typhoon859 - 8/22/12 at 8:56pm
post #304 of 783
Quote:
Originally Posted by ultrabike View Post

 

I think Amps make a difference. Probably not as much as the headphones themselves, but they do IMO. Cables? Probably less so.

 

To compare cables, I would definitively keep everything else the same for comparison purposes, and I would make sure that sufficient power is available. I think power loss through the cable shouldn't be an issue if the source has sufficient headroom to cover it along with the Amp needs.

 

The problem with analog signal is much more difficult to quantify. I can see things like ambient air pressure, air temperature, humidity, how clean your ears are on a given day, your blood pressure at a specific time, position of the headphones on your head, etc to all make a bigger difference than a silver cable and a copper cable. When you start analyzing minutiae like audio cables you would need not only ABX testing on an individual but ABX testing on a significant sample size of individuals to make any kind of statistically relevant judgement. The only real definitive judgement that can be made is on USB transfers since there is a specific protocol and a boolean "right," and "wrong," rather than the infinite shades of gray of analog.

post #305 of 783

....and the time u listen to yor music...dinner time and midnite...a world of difference in my apartment.

the ambient noise level...and visual cues....lighting level....all add/detract from my enjoyment.

 

yes and that braided colored usb cable...once i pluggggg it in....heaven rolled into my living room..

its as scientific as that.

 

L3000.gif

post #306 of 783
Quote:
Originally Posted by Typhoon859 View Post

In any case, what do you say to my previous response? 

 

My answers in blue (assuming you are asking about your original questions/comments.) Hope this helps biggrin.gif

 

Quote:
Originally Posted by Typhoon859 View Post

Maybe I missed it but there is something that's not being addressed which I would like to inquire about. 

 

I've been reading things here and there about USB because of many strange things I've experienced in the past - details like phones not charging with some but charging with others, strange inconsistencies with different sources of power supply with different cables,

 

Some USB cables are defective and non-standard compliant.

 

and a while ago I remember coming across somebody making a claim that their DAC/AMP sounds better with a certain cable over another, saying that the other cable provides more power

 

Depends on the load, but for relatively high impedance loads, power drop through a 28AWG 6" cable shouldn't be a problem.

 

To be honest, in general I've learned absolutely nothing.  Everybody argues against the other and it's incredibly confusing.  All I know is, there is a digital signal; there is a power signal; past certain distances you need power hubs and/or thicker cables. 

 

You need power hubs because the source may not be able to provide enough power. I can tell you that I tried all of my USB cables to try to power my USB 500G drive from my NAS and it did not work. Used a Hub with ANY USB cable and presto! You can get an active (powered) long USB cable from monoprice BTW. Thickness my solve the issue for long haul, but it may not be very practical.

 

Now, my question roots from this person's claim and furthermore after hearing that the FiiO E17 amp I have is powered by USB somehow and it works differently than through S/PDIF - that the power drawn through USB when connected is important. 

 

The S/PDIF and USB interfaces usually are separate circuits and perform differently due to their different implementations... There are more differences than just power drawn.

 

There are many reasons that doesn't make sense to me, but that's maybe because of certain unfounded assumptions on how the device works and maybe because I don't really know what I'm saying past what I can logically infer from what's right in front of me.  All I know is, the power supply makes a difference (like what kind of battery is used as any company for portable audio needs to debate). 

 

It does if it cannot supply enough power to the device. Usually an Amp that sources it's power from USB should be designed with the USB interface standard in mind. It would be flawed to design a 500W USB powered monoblock.

 

I always assumed that the best voltage/current was determined and whatever necessary amount of energy was drawn - difference between the sources simply being how fast they drain.  Apparently not, SO, could a USB cable which supplies more power to a DAC/AMP combo result in a fuller sound?

 

If the source is able to fulfill the DAC/AMP power requirements with plenty of headroom, most likely two standard compliant USB cables will not make a difference in sound fullness. But if the source can't fulfill such power requirements, then no USB cable will be able to fix the problem... Well maybe an active one or a hub can I guess. 

 

Digitally, if I don't hear any breaks/skips, I really don't see how the sound could be affected unless audibly obvious in some other way.  I have a bunch of these cables lying around everywhere and I see no reason why I shouldn't just grab a random one that transmits the data without a hiccup besides if it affects anything to do with power.

 

If things were kosher and you still heard differences between two standard USB cables... Then do tell what cables u used! (do not drink whisky while performing your test though)


Edited by ultrabike - 8/22/12 at 6:45pm
post #307 of 783

Well thank you.  That was nice to see a response to my original post.  I appreciate it, sincerely.

 

I was actually talking to Mikeaj though about a previous response I made to him about something different but nonetheless... 

 

 

"Some USB cables are defective and non-standard compliant."

As has already been suggested to which I have replied, I really doubt it could be such a large quantity.  Plus, I would be hard pressed to believe that the differences can be to such varying degrees.  For instance, I could take a USB cable and plug it into my device from one source; it works.  I could take it to another and it doesn't.  The I could do the same test with another cable and it works in both places.  You could make a point that falls in line with this notion of non-standard compliance and/or them being defective in some way.  What I mentioned though is just one example and it gets even more jumbled with more sources, more cables, more devices - such tests. 

 

Even if this were 100% the issue, it means that USB cables DO VARY, WHATEVER THAT REASON MAY BE.  The question isn't whether correctly made/standard USB cables could make a difference over another correctly made/standard cable.  The question is if any one USB cable THAT WORKS could make a difference?  Even in the example I gave, it clearly means one cable is providing more power than the other.  I don't know how to quantify that but here we are again at the start.  Just saying...

 

"You need power hubs because the source may not be able to provide enough power. I can tell you that I tried all of my USB cables to try to power my USB 500G drive from my NAS and it did not work. Used a Hub with ANY USB cable and presto! You can get an active (powered) long USB cable from monoprice BTW. Thickness my solve the issue for long haul, but it may not be very practical."

It's not just dependent on the source past certain distances.  For reasons I forget, it states on USB.org that due to the nature of the design of USB, there is power leakage that occurs.  I don't know how or why scientifically but that's what was said.  I had a really good article/page about many things where it was broken down but I found something kind of relevant which just would suggest the idea that there's more involved in the transmission of the signal than there would be say a power/audio cable.  http://www.ehow.com/about_5365028_maximum-length-usb-cable.html

 

"The S/PDIF and USB interfaces usually are separate circuits and perform differently due to their different implementations... There are more differences than just power drawn."

Right, I understand that, but I meant like in terms of just the power which would be at the DAC stage.  I meant that contrary to what was mentioned about the difference between e.g. and Optical connection and USB, I thought the DAC was powered the same - with the battery, since there is no power source when connected one way vs. the other.  As I think I mentioned, I thought the USB cable (power wise) just served as a function for charging the battery, not a direct source of power. 

 

"It does if it cannot supply enough power to the device. Usually an Amp that sources it's power from USB should be designed with the USB interface standard in mind. It would be flawed to design a 500W USB powered monoblock."

Right, obviously, but I meant in cases where IT IS enough either way but still different in the amount transmitted. 

 

"If things were kosher and you still heard differences between two standard USB cables... Then do tell what cables u used!"

I never did this test as it's way to prone to placebo.  That's why I came here after searching, assuming there was possibly a well established answer SPECIFICALLY TO THIS and not just to theories which people apply. 

 

 

And uh, thanks again for the response. :)


Edited by Typhoon859 - 8/22/12 at 7:39pm
post #308 of 783
Quote:
Originally Posted by Typhoon859 View Post

 

The question is if any one USB cable THAT WORKS could make a difference?  Even in the example I gave, it clearly means one cable is providing more power than the other. 

 

That is not the only conclusion to draw from that situation... it could just as easily be a slight variation in the connector's pin layout that isn't within the tolerances of a given device. 

post #309 of 783
Quote:
Originally Posted by liamstrain View Post

 

That is not the only conclusion to draw from that situation... it could just as easily be a slight variation in the connector's pin layout that isn't within the tolerances of a given device. 


Hmm, well I dunno...  If the scenario I mentioned is replicable with another device then that wouldn't be it.  Plus, I always tried to align the connection in every way possible when it didn't work in the circumstances that it was a case of bad contact.

post #310 of 783
Quote:
Originally Posted by Typhoon859 View Post

About the E11, that's what I was trying to point out.  It's the one that is flat.

The iPad has a stone flat frequency response through line out.
post #311 of 783
Quote:
Originally Posted by ultrabike View Post

I think Amps make a difference.

i've found that amps that are old or underpowered can sound different. But modern solid state amps that are performing to spec all sound the same at normal listening volumes.
Edited by bigshot - 8/22/12 at 9:27pm
post #312 of 783
Quote:
Originally Posted by bigshot View Post


The iPad has a stone flat frequency response through line out.

Right, through the line out - why it sounds better through an external amp vs. its internal.

Quote:
Originally Posted by bigshot View Post


i've found that amps that are old or underpowered can sound different. But modern solid state amps that are performing to spec all sound the same at normal listening volumes.

As would make sense.

post #313 of 783
Quote:
Originally Posted by Typhoon859 View Post

Right, through the line out - why it sounds better through an external amp vs. its internal.

The iPad, iPhone and iPod are designed to be portable devices. The headphone out is tweaked to work best with the impedence of small, portable headphones to preserve battery life on the go. If you try to listen through the headphone jack using full size studio headphones, it's not going to be able to push it. That's when you dock it and run through the line out. Through line out, the sound quality of the iPad is as good as a standalone home CD player. It doesn't matter what cable you use.
post #314 of 783
Quote:
Originally Posted by bigshot View Post


The iPad, iPhone and iPod are designed to be portable devices. The headphone out is tweaked to work best with the impedence of small, portable headphones to preserve battery life on the go. If you try to listen through the headphone jack using full size studio headphones, it's not going to be able to push it. That's when you dock it and run through the line out. Through line out, the sound quality of the iPad is as good as a standalone home CD player. It doesn't matter what cable you use.

 

That's my understanding. Here is an interesting article regarding headphone impedance and amps:

 

http://www.innerfidelity.com/content/comparison-beyerdynamic-dt-880-32-ohm-dt-880-250-ohm-and-dt-880-600-ohm-headphones

 

Among other things, the headphone impedance should be 10x the Amp impedance to minimize interactions that would result in colored sound.

 

@ Typhoon859: What headphones and DAC/AMP do you use?

post #315 of 783
Quote:

Originally Posted by Typhoon859 View Post
 

The question is if any one USB cable THAT WORKS could make a difference?  Even in the example I gave, it clearly means one cable is providing more power than the other.  I don't know how to quantify that but here we are again at the start.  Just saying...

 

Like liamstrain said, it is more than likely a connectors contact issue. For example, I have a USB cable that works great with my laptops and Sansa Zip. However, I can't get it to work with the USB port in my Ford Fusion car. Does that mean my car does not give my Sansa Zip enough power or that my cable is not cutting it? Nope, found out the USB port contacts in my car are messed up.

 

It's not just dependent on the source past certain distances.  For reasons I forget, it states on USB.org that due to the nature of the design of USB, there is power leakage that occurs.  I don't know how or why scientifically but that's what was said.  I had a really good article/page about many things where it was broken down but I found something kind of relevant which just would suggest the idea that there's more involved in the transmission of the signal than there would be say a power/audio cable.  http://www.ehow.com/about_5365028_maximum-length-usb-cable.html

 

The discussion about transmission line in that article may apply to USB data transmission (480Mbps or faster signals.) That speed is not out of this world BTW, it is possible to transmit 10 Gbps over 100m of Cat 6 (4 pair) cable (10e-12 bit error rate).

 

That said, the power supplied by the USB cable is DC. The loss due to radiation is close to ZERO. Power supplied by the USB interface will experience loss mainly due to the resistance offered by the cable. 

 

Right, I understand that, but I meant like in terms of just the power which would be at the DAC stage.  I meant that contrary to what was mentioned about the difference between e.g. and Optical connection and USB, I thought the DAC was powered the same - with the battery, since there is no power source when connected one way vs. the other.  As I think I mentioned, I thought the USB cable (power wise) just served as a function for charging the battery, not a direct source of power. 

 

I'm a bit confused by your statement. The USB port can be a power source, the optical port can't. The USB cable can be powering the device and charging it's battery at the same time. in that sense it could potentially affect performance. If its all sourced from the battery, I'm not sure why are we talking about USB cables being a problem... Or maybe your point is that you aren't? Dunno...

 

Right, obviously, but I meant in cases where IT IS enough either way but still different in the amount transmitted. 

 

If we are talking about an Amp, if it is enough, then there will not be any differences in the amount received. AFAIK the Amp will draw from the source what it needs regardless of the loss through the cable as long as the source can supply it. My (a bit simplified) understanding is that if an Amp demands a peak power of 2 Watts, and 0.1 Watt is lost in cable X, while 0.12 Watt is lost in cable Y, then the source will supply 2.1 Watts through cable X, and 2.12 Watts through cable Y if the source can supply over 2.12 Watts...

 

I never did this test as it's way to prone to placebo.  That's why I came here after searching, assuming there was possibly a well established answer SPECIFICALLY TO THIS and not just to theories which people apply. 

 

If this was a well established answer, then there wouldn't be a market for > $100 USB cables based on "perceived" life changing sound improvements through them...

 

And uh, thanks again for the response. :)

 

Well I hope all this stuff is helpful biggrin.gif


Edited by ultrabike - 8/23/12 at 11:59am
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