(Resolved) Random earape and loud interference from USB C audio

[Od3stroyer]

Hello

My N3DSXL Capture card that I have self installed (the newest revision with the 6 solder points for USB C audio as well as USB C charging) works flawlessly in video capture, and used to work flawlessly in audio capture. After about maybe 2-3 weeks of use, I start noticing that the audio coming from USB C (Yes, there is NOTHING plugged into the aux port of the 3DS) can sometimes randomly get really loud (I'm talking earape meme levels). This random loudness and static is heard through my PC, as I use headphones in my PC to listen to the audio that the USB C port on the 3DS transmits. I have noticed this behavior on 2 computers, which happen to be the only computers I tested the capture card on. Both my laptop and my desktop. I am using the USB A to USB C connector that Loopy provides within the capture kit for an extra charge. I am also using USB 3.0 ports on both of my computers.

This audio issue is very sporadic - It happens seemingly randomly and can sometimes cause the audio to cut out completely for a few seconds after some unbearable earape. It takes a few seconds for the audio to come back after. Otherwise the audio through USB C is completely fine, and sounds amazing. When it happens though, it is bad.

Some assistance or guidance would be appreciated.

[loopy]

Most likely a soldering issue.

[Od3stroyer]

Here is the soldering I did if you are so inclined to review it:
https://imgur.com/a/dGwchJM

[loopy]

Hmm. That actually looks pretty good.
If there's too much solder underneath the cable, it can spread out between pads. It's hard for me to see, check that that isn't happening.

[Od3stroyer]

Well I'll put it this way - I didn't tin the pads first before putting the audio ribbon cable on as per the instructions. Instead, I lined up the ribbon cable with the pads, and soldered it on that way (Reasons being that tinning the pads just didn't work out on my first attempt on my spare N3DSXL, didn't have a fine enough iron tip). The holes on the audio ribbon cable are very small, smaller than the pads, so I don't think there's too much solder on the pads. (Even so, checking for that is very difficult lol)

I think I may have found a potential culprit to the issue, hear me out. I record 3DS gameplay with OBS, and recently I started using Audio Application Capture (Beta) as the output for the USB C 3DS sound. Prior to this I was using default Desktop audio, and don't remember having any issues with that. Since the Audio Application Capture is in Beta, all of that unexpected noise maybe is a bug of that output? I don't think I have done enough testing yet, but I recorded for 2 hours straight without any unexpected noises using just the desktop audio. I'll keep ya updated.

[Od3stroyer]

Nope, exclusively using Desktop Audio doesn't solve the audio issue either. After waking up, connecting my 3DS to my PC as usual, and turning it on, within 36 minutes of recording the 3DS gameplay via OBS (of course using Desktop Audio just for recording the Audio from USB C) I have the same issue, audio getting extremely loud and some interference that you can hear as well. It goes away after but is still a problem. I have an unlisted video on YouTube showing the issue here:

https://youtu.be/EB7572tNp4k

[Od3stroyer]

Happened again, this time so much worse:

https://youtu.be/H1RaQJGEybw

[loopy]

The soldering is still the most likely culprit. Either that or the board itself is defective.
Is it just the captured audio, or is it messed up on the 3DS as well?

[Od3stroyer]

it is just the captured audio that is messed up. Audio that comes from the speakers, and audio that comes from the aux port is completely fine whenever that garbled up captured audio happens.

[loopy]

Ok.
Well, you can try resoldering it. Or send it in, and I'll take a look at it. Or I can send another board for you to try.
Not sure what else to suggest.