RME ADI-2 DAC FS (AK4493) with Jitter (problem is solved)

[weme]

"ADI-2 DAC (AK4493) with sound problems - THD+N + IMD+N change strongly"

This problem has been reported in the RME forum. Matthias Carstens from RME (here: @MC_RME) identified the problem as jitter.
Workaround: Downgrade to FW27/34
(ADI-2 DAC FS (AK4493) had firmware 34/34)
https://forum.rme-audio.de/viewtopic.php?pid=165958#p165958

No graphics can be posted in the RME Forum. So, now here are some firmware measurements compared to the old ADI-2 (Hardware 1.4) - for your information and if you want to find out whether the firmware 27/34 sounds better as FW34/34. Details about the measurement system can be found in the link above.

Please note:
ADI-2-DAC-FS with FW27/34 and ADI-2-old-HW1.4 (Hardware 1.4) have stable measured values (THD+N / IMD+N).
ADI-2-DAC-FS with FW34/34 has fluctuating measured values (THD+N / IMD+N) - worst case values are shown!

The jitter is << -60 dB (0.1%) and thus not audible. However, we are only measuring a simple, single tone (1 kHz) and this is not a dynamic measurement! With complex audio signals, differences might be audible.

From left to right:

ADI-2-DAC-FS (FW34/34).......ADI-2-DAC-FS (FW27/34).......ADI-2-old-HW1.4

VOL: 0 dB
+12,87 dBu.....................+12,88 dBu...................+12,88 dBu

VOL: -20 dB
-7,12 dBu...........................-7,12 dBu......................-7,17 dBu

VOL: -40 dB
-27.13 dBu.......................-27,13 dBu....................-27,15 dBu

1-ADI-2-DAC-FS (AK4493)_FW34-34_linear_OUT+12.87 dBu.jpg
2-ADI-2-DAC-FS (AK4493)_FW27-34_linear_OUT+12.88 dBu.jpg
3-ADI-2-old_OUT+12.88 dBu.jpg

4-ADI-2-DAC-FS (AK4493)_FW34-34_linear_OUT-7.12 dBu.jpg
7-ADI-2-DAC-FS (AK4493)_FW34-34_linear_OUT-27.13 dBu.jpg
10-ADI-2-DAC-FS (AK4493)_FW34-34_linear_OUT-7.19 dBu_-20dBFS.jpg

 

[AnalogSteph]

Thankfully it's an edge case that only appears with external (SPDIF) clock sync and should be fixed in the next firmware release. The jitter is very close in and quite far down as-is, so masking should take care of it either way.

 

[weme]

MC wrote in the RME forum:

These signals are low frequency jitter and have nothing to do with your other measurements. They don't change values for IMD or THD, and are (of course) not audible. You can easily remove them by changing clock source to INT at the ADI. They are caused by a change in firmware 34/34, and are already fixed (release in the next firmware update). If you need SPDIF sync for your measurements then you could flash the former firmware 27/34:
http://www.rme-audio.de/downloads/fut_m … _27_34.zip

 

[Tigi]

Hello, I have one noob´s question. How can I find out whether the device has firmware 27/34 or 34/34. After turning it on and in the setup I see only information that it is version 34 and the software is from 12/2019.

@MC_RME
Please would you be so kind and specify the timeframe when the new firmware is going to be released?

 

[weme]

Your questions are exactly a part of my thoughts about the new ADI-2 DAC FS - hardware we will get in a few years:
Display of the software version: FPGA / DSP
Display of the hardware version
...

Now to your question:
(1) Connect the ADI-2 DAC FS via UBS to a computer.
(2) Start the flashing programm that suits your needs
- you will get the desired answer
- do an upgrade or a downgrade or quit the programm

https://www.rme-audio.de/adi-2-dac.html

 

[mermayer]

New firmware is released:
"We just released firmware 249/98 for the Pro and 35/34 for the DAC": Re: ADI-2 DAC (AK4493) with sound problems

 

[weme]

RME ADI-2 DAC FS (Firmware 27/34 | 34/34) - IMD values (TDN+N) over the time:

Finally, I present SMPTE measured values graphically over the time. It's amazing to me that the influence of temperature or other things can be completely suppressed by software.

Measured IMD values (TDN+N) with (REW (RTA) after cold start in operating minutes. The RME ADI-2 DAC FS was continuously served with the SMPTE signal.
SMPTE: 60 Hz & 7 kHz 4:1 -1.7 dBFS with REW (RTA: Spectrum 256k Point FFT with 4 Average)
After 120 minutes of operation, the units remained on the power supply and the SMPTE signal was switched off.
After 140 minutes, the SMPTE signal was switched on again.
https://forum.rme-audio.de/viewtopic.php?pid=165958

New firmware is released:
"We just released firmware 249/98 for the Pro and 35/34 for the DAC":

Thanks.
The direct download links:
https://rme-audio.de/downloads/fut_madiface_mac.zip (MAC)
https://rme-audio.de/downloads/fut_madiface_win.zip (WIN)

 

[weme]

We are very satisfied with the firmware 35/34!
With firmware 35/34 everything is great (sound). Also a wonderful room depth - even at low volume (with our Neumann KH310A).
Try firmware 35/34!
Thanks to RME!

Firmware measurement (FW35/34 vs FW27/34):
The deep edges of the test signal (1 kHz) are really unbalanced - this is not a measurement error. Maybe there is a second corner frequency in the range of 1 kHz in the PLL algorithm . But of course this is not a real problem.

MC wrote in the RME forum about the new jitter algorithm:
... (We have) more than 50 dB jitter reduction also at 50 Hz and similar real-world jitter frequencies. Absolutely top-notch for any kind of incoming clock signal.
Later on I will show the difference in behaviour with measurements on my APx555B.
https://forum.rme-audio.de/viewtopic.php?pid=167412#p167412

 

[weme]

The comparative measurements of the firmware have so far been measured under these conditions:
[RME HDSP9632->(SPDIF)] -> [DUT->(analog)] -> [RME HDSP9632]

My comment:
"The deep edges of the test signal (1 kHz) are really unbalanced - this is not a measurement error." is caused by the current RME driver HDSP Series Vers. 4.36.

To reduce interference from the PC hardware, my old RME ADI-2 was inserted for the following measurements. The RME driver HDSP Series Vers. 3.38 was used. All parameters can be found in the graphics:
[RME HDSP9632->(SPDIF)] -> [DUT->(analog)] -> [RME ADI-2->(SPDIF)] -> [RME HDSP9632]

[HDSP9632]: https://www.rme-audio.de/hdsp-9632.html
[ADI-2]: https://www.rme-audio.de/ADI-2.html
[DUT]: ADI-2 DAC FS (AK4493) https://www.rme-audio.de/adi-2-dac.html

Comparison measurements of firmware 27/34 vs 35/34 with a signal of 1 kHz - same measurement - only different X-axis:

Jitter measurements - SR 44.1 kHz:

Conclusion:
The HDSP 9632, the addition with the old ADI-2 and the PC-HW are no good enough to evaluate an ADI-2 DAC. But if units are measured under the same conditions and not at the end of the range, these results can be compared well and thus interpreted. So I was able to find a jitter problem in the firmware 34/34 with software REW. However, the comparative measurements of firmware 27/34 and 35/34 are only suitable for orientation or as a comparison for the few people who still operate an HDSP9632 for measurements.

Here you can get an idea of the errors in my measurement hardware:
ADI-2 Pro FSR as recorder - DUT is an ADI-2 Pro FS with Firmwares 250 or 214:
https://www.audiosciencereview.com/.../lf-jitter-compare-fw250-vs-fw214-png.121282/

Author

Jitter measurement ADI-2 DAC FS (AK4493) with the State-of-the-art analyzer - Audio Precision APx555:
With insignificant deviations - because the measured values are so low:
amirm used the USB interface and a SR of 48 kHz. The jitter measurement is therefore performed with 12 kHz. The USB interface cannot be used with the driver HDSP Series Vers. 3.38. I wanted to spare you the difference between the drivers HDSP Series Vers. 3.38 to 4.36.
https://www.audiosciencereview.com/...on-2-usb-jitter-audio-measurements-png.63557/

Author

So, now be happy about your RME ADI-2 DAC FS or buy one.