Dr-701d noise on hdmi out

[UrsusArctos]

Hello everybody
I hope all in the community are well despite the circumstances.
Driven by these circumstances, in fact, I am driven towards live streaming and this is where I now run into quite an odd problem with my DR-701D.
Setup description:

• Canon EOS D5 Mark IV
• TASCAM DR-701D
• Up to 4 phantom voltage (48V) powered small diaphragm mikes attached to XLR inputs 1 to 4
• Anker Powercore+ 26800 mAh powerbank to power both the DR-701D and the EOS D5 IV
• 5D IV connected to DR-701D's HDMI in
• DR-701D's HDMI out connects with Elgato Cam Link 4K to iMac's or Mac Book Pro's USB 3.0
• OBS Studio 26.1.2 is used to process video and audio.

So far, I used this setup (without the Cam Link) very successfully for quality recordings of chamber music ensembles. Now, caused by the pandemic I get more and more requests for live streaming rather than recording. This is why I wanted to give the Cam Link a try. At first, I was skeptical whether the HDMI signal routed from the 5D IV through the DR-701D would actually transfer a good video image to the computer. I consulted the DR-701D manual and figured that this should actually not be a problem at all and, indeed, video arrives nicely at OBS.
As per the manual, the DR-701D can add up to for audio channels to the HDMI signal. Sounds like the perfect playground for me as it would allow me to push pretty much the same quality out as a livestream as I would otherwise only record.
However, it seems the HDMI out of the DR-701D is electronically not clean as it puts some knacking noise into the line every few seconds but not regularly. Strangely, the right hand side channel of the stereo signal seems to be more affected than the left hand one.
I did isolate the problem down to the HDMI out of DR-701D. The noise is also present when the HDMI off the 5D IV is detached from the DR-701D. it is also present in all HDMI out settings regardless of channel selection. The noise is also present independent of the attached mikes, including the internal ones. The Cam Link isn't the source of the problem either. The noise is gone when I attach the 5D IV directly to the Cam Link and have the audio fed into the camera via the DR-701D's camera out into the 5D's external mike port.

To make a long story short, I wonder if someone else here can tell of similar experiences and if so, if these people found a cure to this problem.
I find the idea of a single connection into the computer very elegant but obviously only if it provides noise free audio input.
Thanks for any thoughts that might help.

Edit: I updated to firmware 2.10. However, the new firmware did not solve the problem.

 

[UrsusArctos]

Here comes an update, which gives the whole saga a very positive twist. I hope others may benefit from this as well.
I was pretty desperate and therefore launched several initiatives in the hope the one would lead me to salvation. And that is exactly what happened, credit to TASCAM support. TASCAM forwarded my support request to the their main distributor in the country I live. Soon enough, a friendly person contacted me and inquired some detail information about settings, which I readily provided.
You will not imagine how simple the solution is:
OBS Studio allows audio sampling at either 44.1 or 48 kHz. My DR-701D was set to 96 kHz for no good reason other than "more of the good stuff can only be better".
Once I had both the OBS's and DR-701D's sampling frequencies set to 48 kHz, the noise was gone.
I praised the DR-701D before very highly and now I can also recommend it for high quality live streaming of contents where audio is equally if not more important than video. This is really the one and only tool I know that is meets the requirements 1 man audio/video crews so perfectly.