Now into the details
This firmware update for the ADI-2 Pro and ADI-2 DAC extends the Class Compliant compatibility. While all our Class Compliant devices work perfectly on Mac OS X, iOS and Linux, we are aware that in some other cases they don't. The ADI-2 DAC was the perfect candidate to change that. We got a Squeezebox Touch from a fellow RME user, and also examined why Windows 10 recognizes, but won't start the DAC as playback device (as you may know since Windows 10 1709 a UAC2 driver is part of the OS, so it should work right out of the box).
The new FPGA firmware 177 (Pro) and 17 (DAC) is the result:
- Logitech's Squeezebox Touch with EDO via USB, which did not show the ADI-2 DAC at all, now recognizes it and can use it as audio source via USB.
- Windows 10 now fully accepts the ADI-2 Pro and DAC as 2 channel record and 2 channel playback device. PCM up to 384 kHz, and DSD up to DSD256 are supported.
The latter has been tested with various software, among them Roon. While Roon supports ASIO it can also use Wasapi to change the sample rate automatically based on the sample rate of the currently played file. This also works when changing to DSD (set to 'DSD via DoP'), everything automagically within a mixed PCM/DSD playlist. And although Windows audio is limited to 384 kHz, DSD256 playback worked perfectly - which switches the ADI to 705.6/768 kHz sample rate.
So basically there is no driver installation necessary under Windows 10 anymore - unless you want to use ASIO and DIGICheck and the Firmware Update Tool. And please note, once the driver is installed the same restrictions apply as before: with WDM there is only one single sample rate available, no automatic sample rate switching from the application via WDM or Wasapi - only via ASIO.
There is some more going on with the Pro. When switched to CC mode Multi-channel Windows sees 6 input and 8 output channels. In our opinion Windows' UAC2 driver needs serious updates to work flawlessly in multichannel mode, the list of issues is long, and therefore we can not recommend using it in that mode right now. Basically WDM/DirectSound somehow works, but the more interesting Wasapi Exclusive and many other things in handling and configuration are not working at all.
Note that in case you want to try it yourself: Windows already fails to adapt between Multi-channel mode and Stereo mode. When changing the mode you have to enter the Device Manager, Audio, Video and Game controllers, select the ADI-2 Pro, click on 'Uninstall'. After that go to Actions - Scan for Hardware changes. The ADI-2 Pro is back and will work now in the new mode. Going back to the former mode - same procedure again.
We hope that other reported Class Compliant incompatibilites (for example some Synology NAS, Sony HAP-S1) are also solved by firmware 177/17. Please report back here. And in case of trouble with the ADI-2 Pro make sure it is in Stereo mode.
These changes will be ported to our other CC capable devices sequentially. I also would like to point out that the changes do not affect operation under Windows with WDM/ASIO driver, iOS or Mac OS X, with one exception: all I/O channels now have names, so under Mac OS X outputs 1 to 8 changed to Analog 1/2, Phones 3/4, AES and SPDIF (Windows does not read or use the channel names). Whether this makes changes necessary in existing DAW projects or not needs to be seen.