[kumar402]

I'd be careful with some of those devices and not just blindly buying because of the reputable brand name. I don't know much about those devices as I haven't researched them but I know the uptone etherregen is not good.

As in the case with the ifi igalvanic, I had one and it degraded the sound quality on my system quite severely. It did reduce noise but the consequence in the way it was doing it was that it compressed the sound, flattened the bass and killed the liveliness in the music.

Ifi makes some great products but the igalvanic was not one of them, theres a reason why they discontinued it.

I haven’t used Etherregen but have used generic FMC module powered with 5v LPS to good effect.
Not sure what Etherregen or Sonore Optical module offers.

 

[dougms3]

I haven’t used Etherregen but have used generic FMC module powered with 5v LPS to good effect.
Not sure what Etherregen or Sonore Optical module offers.

Yeah, I know uptone makes great products but not everything is a win.

Etherregen is very similar to the igalvanic but unfortunately the effect is also similar.

 

[hsg120]

I have not used them myself except Intona is known brand for galvanic isolation. I only suggested as OG poster wanted to use USB in to USB out. So for galvanic isolation Intona is best out there.
There is no point to have fancy clock for USB in to USB out device.

Yep sorry, I wasn't being precise when I said "DDC". Apologies! xD

I was not previously aware of Intona or ISO Regen, so thanks to those who shared those with me! That is more or less what I was after with my initial question. I'll have to look into those more deeply. I was previously aware of the iGalvanic, but I've used some of ifi's cheaper equipment before and wasn't really impressed. So I was hoping for something more than just an inline dongle.

I just thought it was weird that DDC's with a USB input almost invariably exclude a USB output, but a lot of the replies here help that make more sense though.

 

[REXNFX]

Yep sorry, I wasn't being precise when I said "DDC". Apologies! xD

I was not previously aware of Intona or ISO Regen, so thanks to those who shared those with me! That is more or less what I was after with my initial question. I'll have to look into those more deeply. I was previously aware of the iGalvanic, but I've used some of ifi's cheaper equipment before and wasn't really impressed. So I was hoping for something more than just an inline dongle.

I just thought it was weird that DDC's with a USB input almost invariably exclude a USB output, but a lot of the replies here help that make more sense though.

You asked a good question. If DDC's also included a USB decrapifier they could be used with DACs that prefer USB and DSD.

 

[keenerz]

Oddly a Schiit Urd would technically also kind of do what you want.

 

[dougms3]

Yep sorry, I wasn't being precise when I said "DDC". Apologies! xD

I was not previously aware of Intona or ISO Regen, so thanks to those who shared those with me! That is more or less what I was after with my initial question. I'll have to look into those more deeply. I was previously aware of the iGalvanic, but I've used some of ifi's cheaper equipment before and wasn't really impressed. So I was hoping for something more than just an inline dongle.

I just thought it was weird that DDC's with a USB input almost invariably exclude a USB output, but a lot of the replies here help that make more sense though.

It would be much easier to have a usb output but the reason its not offered because its always the last choice for optimal audio quality, simple as that.

If you're spending money on a ddc, you're obviously looking for the best audio quality out of your system, so while convenient, usb is not ideal.

It gets quite complex, I researched it before but I don't remember the technicals as this is quite boring to me.

"I2S is a electrical serial interface used to transmit PCM data from one device to another. The interface has a line used to delineate frames called the frame clock, a line for marking individual bits called the bit clock and 1 or more lines for the data. At the start of each frame clock a PCM sample is serialized bit by bit with a high voltage for a 1 and a zero voltage for a 0. The bit is held at that value for the entire duration of a bit clock and then it moves onto the next bit."

https://en.wikipedia.org/wiki/I²S#Details

For example, the native format of a cd player is i2s. To send the data to a dac, it must be converted into a transportable form via the available connections on the cd player and dac (rca, spdif, etc). Since i2s is not a common type of connection as it was never meant to be used with cables, the data must be converted to something like spdif, then gets converted back to i2s.

As you can see, its not ideal.

 

[hsg120]

It would be much easier to have a usb output but the reason its not offered because its always the last choice for optimal audio quality, simple as that.

If you're spending money on a ddc, you're obviously looking for the best audio quality out of your system, so while convenient, usb is not ideal.

USB and SPDIF are both just digital communication protocols, both with pros and cons. And I'm not sure that I follow what the I2S stuff was about--maybe you would be so kind as to elaborate your point for me? I would be curious to hear more about the source of your argument.

I personally choose to use USB because it provides more signal bandwidth than SPDIF, and almost invariably generates less jitter due to superior clocking. So then, what is the inherent advantage that SPDIF offers over USB for audio applications?

 

[REXNFX]

It would be much easier to have a usb output but the reason its not offered because its always the last choice for optimal audio quality, simple as that.

If you're spending money on a ddc, you're obviously looking for the best audio quality out of your system, so while convenient, usb is not ideal.

It gets quite complex, I researched it before but I don't remember the technicals as this is quite boring to me.

"I2S is a electrical serial interface used to transmit PCM data from one device to another. The interface has a line used to delineate frames called the frame clock, a line for marking individual bits called the bit clock and 1 or more lines for the data. At the start of each frame clock a PCM sample is serialized bit by bit with a high voltage for a 1 and a zero voltage for a 0. The bit is held at that value for the entire duration of a bit clock and then it moves onto the next bit."

https://en.wikipedia.org/wiki/I²S#Details

For example, the native format of a cd player is i2s. To send the data to a dac, it must be converted into a transportable form via the available connections on the cd player and dac (rca, spdif, etc). Since i2s is not a common type of connection as it was never meant to be used with cables, the data must be converted to something like spdif, then gets converted back to i2s.

As you can see, its not ideal.

PS Audio , who first used i2s state there is NO Difference between i2s and USB.

 

[dougms3]

USB and SPDIF are both just digital communication protocols, both with pros and cons. And I'm not sure that I follow what the I2S stuff was about--maybe you would be so kind as to elaborate your point for me? I would be curious to hear more about the source of your argument.

I personally choose to use USB because it provides more signal bandwidth than SPDIF, and almost invariably generates less jitter due to superior clocking. So then, what is the inherent advantage that SPDIF offers over USB for audio applications?

Audio files are very small, never going to come close to maxxing out the usb bandwidth transferring audio files.

The simple answer is noise. USB is a very noisy transfer method. And by noise, I mean EMI. It transfers noise from a pc, one of the worst sources for high quality audio and contaminates the destination with this noise. On top of that whether you want it or not, a usb cable carries 5v power in the same cable as the data, further contaminating the audio signal.

 

[dougms3]

PS Audio , who first used i2s state there is NO Difference between i2s and USB.

Perhaps the problem is PS audio's implementation and not the i2s connection.

While they're well known for their power products, no one is impressed with i2s implementation.

 

[REXNFX]

Perhaps the problem is PS audio's implementation and not the i2s connection.

While they're well known for their power products, no one is impressed with i2s implementation.

You're welcome to your opinion but that's all it is.

 

[dougms3]

You're welcome to your opinion but that's all it is.

And you're welcome to your opinion, and thats all that is.

Have you listened to a device with i2s to compare?

 

[REXNFX]

And you're welcome to your opinion, and thats all that is.

Have you listened to a device with i2s to compare?

Not yet, if I get a DAC with the appropriate input I will.

 

[medon]

I have owned several 'hi-fi' DDCs (e.g. Denafrips Gaia, Topping U90, Singxer Su6, etc) and often wondered why they almost invariably have a USB input, but never a corresponding USB output.
...
I assume there's a reason why, but would be so grateful if someone would please fill me in.

Just a guess:
USB audio is the only protocol (within SPDIF/i2s/AES-EBU/ USB) that is asynchronous. Means: There is some back&forth in communication between sender and receiver. In the end, B in USB stands for "bus". All other protocols are not busses.

With these other types (i2s / SPDIF / AES-EBU) the sender only sends, and doesn't listen to the receiver.

In this case the sender has an easy job: To output a noise- and jitter-free signal. Done . Only the receiver that has to adapt to what's coming in, using maybe several PLL / reclocking stages before actually feeding the DAC.

Guess, might be completely off:
With USB, because of the back&forth thing, all kinds of hard-to-predict results between sender and receiver might happen, and it is quite a bit harder to implement a really robust audiophile USB sender as well as receiver.
In the end, two parties need to adjust to each other in a graceful way - the sender needs to make it as easy as possible for the receiver to get into the groove. And the receiver shouldn't make life too hard for the sender by issuing all-too randomly timed "send more data, NOW!" requests.

 

[hsg120]

Audio files are very small, never going to come close to maxxing out the usb bandwidth transferring audio files.

The simple answer is noise. USB is a very noisy transfer method. And by noise, I mean EMI. It transfers noise from a pc, one of the worst sources for high quality audio and contaminates the destination with this noise. On top of that whether you want it or not, a usb cable carries 5v power in the same cable as the data, further contaminating the audio signal.

Ahh yes, apologies, what I mean by "bandwidth" is that SPDIF is limited to 24bit/192kHz, whereas USB can support up to 32 bit/768 kHz. The maximum communication throughput is totally irrespective of the audio file size. USB can support digital formats like native DSD for instance, whereas SPDIF has limited support (i.e. only DSD over PCM). Just one example...

And when you say that USB is "very noisy," what are you basing this on, exactly? Because from what I have seen, USB usually offers lower jitter, and ultimately less noise and distortion than SPDIF. Example--

https://www.thewelltemperedcomputer.com/Intro/SQ/USB_SPDIF.htm

In fact, if you follow Amir's posts on ASR, he demonstrates this fact regularly when he evaluates the noise and disortion coming from various DAC's inputs. So, I'm curious to learn where you are seeing SPDIF so routinely outperforming USB.