Yes I think you're right, the RME ADI-2 does not include galvanic isolation, but from reading various technical posts on ASR and elsewhere, I understand that DAC developers now have other ways of mitigating noise from the USB source. This also applies to other cutting edge DAC products from Topping etc, but of course, being proprietary products, the techniques they employ are not openly discussed on DIY forums.
So it appears to me that galvanic isolation is now somewhat old-school, but the proof, as they say, is in the pudding ...
Sure, try a external USB isolation device, and see if you can hear any difference.
🙂)
Maybe Jan will be so kind to measure that "PWM noise" from his iPad connected to the ADI-2-Pro ;-)
Martin
Start here
Review and Measurements of RME ADI-2 DAC | Audio Science Review (ASR) Forum
and here
RME ADI-2 FS Version 2 DAC and Headphone Amp Review | Audio Science Review (ASR) Forum
I think that Amir's measurements show that noise from USB is low, or at least the noise does not adversely affect the final analogue output of the DAC.
And you will see comments from RME and Topping along the lines of "immune to USB noise" - but they will not give you any technical hints about how they achieve this.
Thanks for the links, boths threads are rather long, it will take me a while 🙂
I wonder what USB noise is meant. Both devices have external power supply, the USB power is not used (I assume as there is no reason to do so with an external PSU available). Only the USB ground is shared, which opens possibility of a ground loop in the measurement but I do not know if that is what was meant. A proper measurement setup should eliminate any ground loop effect, IIUC.
I can imagine noise on the data lines but have not seen any measurement of its effect on proper async device.
Perhaps does the "immune to USB noise" mean "we do not use the USB power"? Maybe not, I really do not know.
I wonder what USB noise is meant. Both devices have external power supply, the USB power is not used (I assume as there is no reason to do so with an external PSU available). Only the USB ground is shared, which opens possibility of a ground loop in the measurement but I do not know if that is what was meant. A proper measurement setup should eliminate any ground loop effect, IIUC.
I can imagine noise on the data lines but have not seen any measurement of its effect on proper async device.
Perhaps does the "immune to USB noise" mean "we do not use the USB power"? Maybe not, I really do not know.
You may know it already, but you will need the official Apple Lightning-to-USB Camera Adapter, of which there are presently two versions:
- Apple part number MD821AM/A which only supports self-powering of the i-device.
- Apple part number MK0W2AM/A which is larger, and supports external powering of the i-device.
Sorry for sidetracking but since you have lots of know-how regarding Linux audio what is the appropriate setup for a linux desktop if used for measurements with REW? Seems that Alsa, Pulseaudio, Jack etc. have somewhat overlapping functionalities and some don't even seem to work with REW.
No I didn't know but was wondering about that. Trust Apple to find yet another way to extract money from us - € 40 for a 4" cable!
Sidetrack: the EU made it a law that all mobile devices from next year I think should mandatory have a USB-C power charging connector to cut down on the dozens of different power adaptors you now need in an average household.
Jan
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As there already is a thread on REW I added my question there: Howto - Distortion Measurements with REW.
^As far as I can tell, the Pi2AES does not have an USB output, which Jan needs for his USB DAC.
Jan,
Honestly I am shocked, as smart as you are being intimidated by a raspberry pi? In the time you have spent on this post I built a roon server out of a I5 nuc I had laying about and installed 5 different versions of pi from Allo bridge, pi-4 and 3 pi-3 running dedicated dacs pi hats etc.. I have them all over the house some wired some not -on my main living room system, office system, headphones in the bedroom, speakers on the patio and hot tub, one on my tech bench. I even have one I am putting in a frog in the garden. I have several cheap android tablets laying about and use my iPhone and iPad as well. Ropiee is so easy for the end points once you figure out 1 its a piece of cake from there. Roon is great I ripped all my music and then signed up with Qubuz. Roon plays a cd I pick and then grabs something new off Qobuz loving it. Yes it could be argued it is not the most hi-end solution but to my ears it’s good enough. It has made Music fun again for me.
Bil
Honestly I am shocked, as smart as you are being intimidated by a raspberry pi? In the time you have spent on this post I built a roon server out of a I5 nuc I had laying about and installed 5 different versions of pi from Allo bridge, pi-4 and 3 pi-3 running dedicated dacs pi hats etc.. I have them all over the house some wired some not -on my main living room system, office system, headphones in the bedroom, speakers on the patio and hot tub, one on my tech bench. I even have one I am putting in a frog in the garden. I have several cheap android tablets laying about and use my iPhone and iPad as well. Ropiee is so easy for the end points once you figure out 1 its a piece of cake from there. Roon is great I ripped all my music and then signed up with Qubuz. Roon plays a cd I pick and then grabs something new off Qobuz loving it. Yes it could be argued it is not the most hi-end solution but to my ears it’s good enough. It has made Music fun again for me.
Bil
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Bill I apologize for shocking you, I hope for a speedy recovery 😎 !
But it's not so much intimidated, I am fairly certain that I could set something up like that if I really want, but I would take much longer than you! It's just that I have several other things I want to work on, things that have been on the backburner too long like my direct drive ESL amp.
But I'd love to get together again in person at a BAF, but it won't be this year of course!
Jan
But it's not so much intimidated, I am fairly certain that I could set something up like that if I really want, but I would take much longer than you! It's just that I have several other things I want to work on, things that have been on the backburner too long like my direct drive ESL amp.
But I'd love to get together again in person at a BAF, but it won't be this year of course!
Jan
Wow,
Good memory, I met you and Siegfried at the I think second burning amp, I am quite shy and both of you were so friendly and made me feel welcome it made a lasting impression on me.Having Siegfried pass was a sad moment for me.
Bill
Good memory, I met you and Siegfried at the I think second burning amp, I am quite shy and both of you were so friendly and made me feel welcome it made a lasting impression on me.Having Siegfried pass was a sad moment for me.
Bill
Have you looked at the Pecan-pi Orchard audio?it is fully build and can be purchased as a endpoint or standalone steamer.
Bill
Bill
For some reason you made an impression. 😎
That Orchard is about the same price as the Zen Streamer, a bit more expensive.
I'm waiting for the Zen first to see how it comes across.
Jan
That Orchard is about the same price as the Zen Streamer, a bit more expensive.
I'm waiting for the Zen first to see how it comes across.
Jan
IMO the RPi is convenient for devices which take advantage of the RPi's digital interfaces - I2S, I2C for DAC/clock gen control, SPI or DSI for display, GPIOs for push buttons, etc. For a more involved project the Compute Module 4 offers much better integration options and onboard eMMC.
But for a USB-DAC streamer I do not see any advantage compared to headless/fanless x86 devices. E.g. a refurbished (A quality, no visual difference from a brand new piece) thin client from HP, Dell, or Fujitsu with professional case, top quality power adapter, conveniently placed connectors costs the same or less than plain RPi4 (which needs a PSU, a quality SD card, a decent case). Most thin clients come with 4GB+ SSD. I would use an mSATA SSD anytime over an SD card and the price is same.
All thin clients support suspend-to RAM sleep and wake-on-LAN, unlike RPi, allowing much faster startup. Power button press - sleep, power button press - wakeup. Absolutely no problems with weak PSUs etc.
Also software upgradability of an x86 machine with regular bios and USB boot is way easier for someone who does not want to delve into linux details.
But for a USB-DAC streamer I do not see any advantage compared to headless/fanless x86 devices. E.g. a refurbished (A quality, no visual difference from a brand new piece) thin client from HP, Dell, or Fujitsu with professional case, top quality power adapter, conveniently placed connectors costs the same or less than plain RPi4 (which needs a PSU, a quality SD card, a decent case). Most thin clients come with 4GB+ SSD. I would use an mSATA SSD anytime over an SD card and the price is same.
All thin clients support suspend-to RAM sleep and wake-on-LAN, unlike RPi, allowing much faster startup. Power button press - sleep, power button press - wakeup. Absolutely no problems with weak PSUs etc.
Also software upgradability of an x86 machine with regular bios and USB boot is way easier for someone who does not want to delve into linux details.
HP
Something like this?
https://thinclientspecialist.nl/web...bished/refurbished-hp-t630-w10/?number=&c=263
Something like this?
https://thinclientspecialist.nl/web...bished/refurbished-hp-t630-w10/?number=&c=263