USB cable supposedly improving DAC sound quality? How can I take other posts seriously after that? - Page 11  

Quote:

Originally Posted by proton007 

I think the digital signal part has already been addressed well. Regarding the power part, I can say this. One, the USB power is considered to be one of the cleaner sources out there.

Secondly, digital chips work within a certain min/max range. If you look at the DAC datasheet, most of them use VDD as reference. So it doesn't matter what VDD is, as long as its between 3.3-5V. Thats a big range, even if you consider HF noise. So unless you USB cable is so bad it cannot even transfer 3.3V reliably, it should not cause an issue.

I don't think many op-amps operate well under 5V though, which is where the external power supply comes in.

Quote:

Originally Posted by liamstrain

 

Aside from my personal experience and the testimony of my friends and co-workers in the field? No I do not. It would be interesting to go collect it though. A poll of sound engineers would be interesting - though I don't know if I have the time to follow with a test to see if they could match a headphone to its charts... I'll see if I can put one together and send it around.

 

Do you have any evidence for your assertion that would render my experiment unnecessary?

That sounds like a good idea.

No, I don't have evidence of a lack of evidence, I just have a lot of data pointing in that direction.  Until there is at the very least a survey which can accurately match graphical data to what we hear, I have no reason to believe the graphical data is currently very sophisticated or factual.

When people counter with the premise that if you're hearing something which isn't measureable it's psychoacoustics, I take that as a belief system, not science.

Quote:

Originally Posted by mikeaj 


Whoa wait a sec. USB power from most computers is clean? Compared to what?
Secondly, even if a lot of chips can operate fine with a range of supply voltages, some may be preferred over others. A DAC is an analog chip anyhow, at least for the purposes of conditions needing to be more exacting for good performance. And certainly if there's enough noise on the supply rails, that impacts performance. What do you think anybody lists or advertises good PSRR?

Compared to any alternative 5V supplies. And yes, PSRR exists on both supply and DAC side as well. Add to that the inbuilt noise filtering (+- 10%) of the chip. If the noise is truly noise (read random), it can be removed sufficiently well, so much that there is negligible performance difference, even if this perfect power supply exists.

Quote:

Originally Posted by kiteki 

 

 

I don't think many op-amps operate well under 5V though, which is where the external power supply comes in.

A DAC is not an op amp.

Quote:

Originally Posted by proton007 

 

A DAC is not an op amp.

Every USB DAC has an op-amp afaik, hence the comment.  A DAC which only has optical out doesn't have any sound quality or performance to discuss.

Quote:

Originally Posted by kiteki 

Every USB DAC has an op-amp afaik, hence the comment.  A DAC which only has optical out doesn't have any sound quality or performance to discuss.

It depends...

Some DAC chips have built in op amps for their output and power them with cool tricks like built in negative charge pumps for a bipolar supply with a >5V difference so they can work just fine off of a single low voltage supply like you can get from properly filtered USB power.  Those chip don't need a separate opamp chip so it depends on your definition.

Are you talking about the ESS ES9023?  I have that one, it sounds nice.

Quote:

Originally Posted by kiteki 

Are you talking about the ESS ES9023?  I have that one, it sounds nice.

That's the one I was thinking of.  I remember that there are some other chips with similar tricks but I can't keep all those model number in my head at once so that's the only model I have off the top of my head.

I'll have one soon enough too.

Quote:

Originally Posted by kiteki 

 

No, I don't have evidence of a lack of evidence, I just have a lot of data pointing in that direction.  

 

I would be curious to see that data, some time.

     Quote:

Originally Posted by maverickronin 

 

That's the one I was thinking of.  I remember that there are some other chips with similar tricks but I can't keep all those model number in my head at once so that's the only model I have off the top of my head.

 

I'll have one soon enough too.

Mine looks kinda like that but actually uses an op-amp (LME49610), I'll most likely pick up the ODAC out of curiosity just to make sure they sound identical.

hello Kiteki

i didnt quite believe USBcables can affect quality of sound, but i had prior good results with my powercables n rcas...

( so the bias placebo blablabla is fully loaded above my neck )

and since i am no engineer, the only way is to buy one and hear it for myself.

bought a LAT usbcable..wow more than happy with the improved depth n added clarity.

then i bought another...shant tell u where i hook this cable to.....

i know its technically 0s and 1s...

0 being the cable is pulled out, and 1 being the cable is inserted.

Thats as simple as it gets ...

and i carry on enjoying the music.

These 10pages of postings is way off my technical knowledge...but v interesting read.

Quote:

Originally Posted by kiteki 

Mine looks kinda like that but actually uses an op-amp (LME49610), I'll most likely pick up the ODAC out of curiosity just to make sure they sound identical.

What model is yours?  If it was carefully designed they probably will sound the same but if it wasn't then it might not.  Implementation is everything in that kind of thing and the ODAC had a lot of work go into the design so it could get with in 1dB of the best case scenario datasheet specs from just USB power.  Some companies just slap the DAC chip on a board and quote the datasheet specs as if they actually meant something at that point.

     Quote:

Originally Posted by liamstrain 

Quote:

Originally Posted by kiteki 

 

No, I don't have evidence of a lack of evidence, I just have a lot of data pointing in that direction.  

 

I would be curious to see that data, some time.

I posted the data in post #130 and #108.

The fact you need to conduct a survey is a data point in the direction of evidence of a lack of evidence.

If you want to continue the discussion or you're actually going to poll sound-engineers if they can see the difference between a STAX and an IEM on paper (minus the isolation spec., which isn't relevant) feel free to start a new thread on the topic.

Originally Posted by maverickronin 

 

What model is yours?  If it was carefully designed they probably will sound the same but if it wasn't then it might not.  Implementation is everything in that kind of thing and the ODAC had a lot of work go into the design so it could get with in 1dB of the best case scenario datasheet specs from just USB power.  Some companies just slap the DAC chip on a board and quote the datasheet specs as if they actually meant something at that point.

Is there an ODAC thread we can discuss that in?

Originally Posted by Lorspeaker 

hello Kiteki

 

i didnt quite believe USBcables can affect quality of sound, but i had prior good results with my powercables n rcas...

( so the bias placebo blablabla is fully loaded above my neck )

and since i am no engineer, the only way is to buy one and hear it for myself.

bought a LAT usbcable..wow more than happy with the improved depth n added clarity.

then i bought another...shant tell u where i hook this cable to.....

 

i know its technically 0s and 1s...

0 being the cable is pulled out, and 1 being the cable is inserted.

Thats as simple as it gets ...

and i carry on enjoying the music.

 

These 10pages of postings is way off my technical knowledge...but v interesting read.

Hello Lorspeaker.

Indeed, you just have to buy stuff, and hear it for yourself.

Not familiar with the LAT USB cable.

Have fun with this thread.

Quote:

Originally Posted by kiteki 

Is there an ODAC thread we can discuss that in?

I have no idea...