Why does external USB interface sounds better than internal USB interface?

[Windows X]

Thinking logically, internal USB interface should have lesser chain of connection, shorter I2S connection to DAC without encapsulation on AES/SPDIF and stuff. My friend conduct some listening tests with Eximus DP1 and Stello U3. We found that using Stello U3 as external interface to AES/Coaxial input sounds better than internal USB interface. Both U3 and DP’s internal USB audio should have about the same quality. They even share the same driver and firmware.

 

After further tests with USB isolator and noise filter on tested computer machine, we found they minimized the difference between internal and external USB interfaces significantly. We could say that the reason why internal USB interface sounds worse is because DAC itself gets pollution from direct contact with computer audio source. By using external USB interface, DAC itself receives signal from encapsulated stream from USB interface box isolating pollution from USB connection.

 

However, it’s unavoidable for DSD to be played from direct USB connection. I think it’s important to reduce the pollution in computer audio source or suppress its effects with isolator or noise filter with optimal implementation.

[17629]

You can use much higher quality parts, and not have to worry about conforming to a form factor with an external unit.

[Jabs1542]

Thinking logically, internal USB interface should have lesser chain of connection, shorter I2S connection to DAC without encapsulation on AES/SPDIF and stuff. My friend conduct some listening tests with Eximus DP1 and Stello U3. We found that using Stello U3 as external interface to AES/Coaxial input sounds better than internal USB interface. Both U3 and DP’s internal USB audio should have about the same quality. They even share the same driver and firmware.

 

After further tests with USB isolator and noise filter on tested computer machine, we found they minimized the difference between internal and external USB interfaces significantly. We could say that the reason why internal USB interface sounds worse is because DAC itself gets pollution from direct contact with computer audio source. By using external USB interface, DAC itself receives signal from encapsulated stream from USB interface box isolating pollution from USB connection.

 

However, it’s unavoidable for DSD to be played from direct USB connection. I think it’s important to reduce the pollution in computer audio source or suppress its effects with isolator or noise filter with optimal implementation.

 

And thus the Regen was born

[barrows]

This is only because many DAC manufacturers still do not implement an onboard USB interface properly. It is really maddening, as this gives USB a bad name, and unnecessarily so. Yes, it does cost a bit more to do it right, but DACs above $2K have no excuses as far as I am concerned.

[jtwrace]

This is only because many DAC manufacturers still do not implement an onboard USB interface properly. It is really maddening, as this gives USB a bad name, and unnecessarily so. Yes, it does cost a bit more to do it right, but DACs above $2K have no excuses as far as I am concerned.

 

Who does it right in your opinion?

[barrows]

Who does it right in your opinion?

 

I am not aware of how USB is implemented in every DAC out there. One company who does it right is Ayre, I am sure there are others.

I do find it disappointing when I open the case of a $3K or more DAC and find that the I2S lines from the USB receiver are not isolated, and share a ground with the DAC and master clock(s).

[17629]

I am not aware of how USB is implemented in every DAC out there. One company who does it right is Ayre, I am sure there are others.

I do find it disappointing when I open the case of a $3K or more DAC and find that the I2S lines from the USB receiver are not isolated, and share a ground with the DAC and master clock(s).

 

I thought I2S was a DIN type connection? Do you need some type of adapter for USB?

[mansr]

I thought I2S was a DIN type connection? Do you need some type of adapter for USB?

I2S is used between integrated circuits on a PCB. No connectors involved. Occasionally it is used with external connections, but that's more of an exception and not what it was intended for.

[shitaleo]

DACs above $2K have no excuses as far as I am concerned.