Installed an MPU9211 in my Space Station today. It works great except the sound quality is terrible. It's more noticeable with the SFX and voice. When SFX and voice are played, there's so much noise that I can barely understand what is said. I swapped the MPU with a good working System11B MPU and the sound is much better. When there is no sound being played, the humming noise is way louder with the MPU9211 than the System 11B MPU.

I haven't put the scope on it so I don't know what's causing this, but there's an issue with my board (if not all of them) when installed in Space Station.

I emailed J ROD at Rottendog explaining my problem. Hopefully someome figures out a fix/mod.

Jim from rottendog called me today to enquire about the issue. Kudos to Rottendog for great customer service!!

I just uploaded 2 videos on YT. One is Space Station running with the MPU9211. The other is the same Space Station running with the original sys 11B MPU. I'm still fixing up the sys 11B board, hence the garbled displays. I think I have a broken trace to the display PIA. I find that the MPU9211 has more distortion than the original. It's more noticeable with the SFX and speech, so I did not bother uploading the soundtrack.

Original sys 11B MPU sound:

MPU9211 sound:

Listened to it again for a few minutes and it does seem that only the speech sounds worst. The SFX sound OK.

Has anyone listened to the two YT videos I posted? Can anyone else hear thw noise/distortion?

Once I'm done fixing the original board I plan to install it and keep the rottendog one as a spare just because of the distorted speech.

On a side note, I noticed you live in Moncton. I live about 40 mins from there.

They had got back to me requesting some audio clips to compare both boards. I emailed them the audio clips of both boards and I haven't heard anything back yet.