Soundcard background noise when MIDI controller is plugged

[tuzzo]

Hello guys!
I'm using ubuntu 20.04 with kernel 5.4.0-47 lowlatency and a "Lexicon Alpha" USB soundcard.
When i use the soundcard with my AKAI midi controller, i start hearing a background noise. These two devices correctly worked toghether in previous systems, now they are not. I don't know if it's a software related problem...
Thanks in advance.

[bluebell]

Hello guys!
I'm using ubuntu 20.04 with kernel 5.4.0-47 lowlatency and a "Lexicon Alpha" USB soundcard.
When i use the soundcard with my AKAI midi controller, i start hearing a background noise. These two devices correctly worked toghether in previous systems, now they are not. I don't know if it's a software related problem...
Thanks in advance.

Can it be a ground loop? That happens when you have more than one device with protective earth connected (in the socket) AND use unbalanced cables (cinch, mono jack). Effects can be a hum and/or hiss, sometimes dependent on mouse movenments.

Solution:
Use balanced cables (best solution if your devices have balanced inputs/outputs) or use an audio transformer.

[tuzzo]

Hello guys!
I'm using ubuntu 20.04 with kernel 5.4.0-47 lowlatency and a "Lexicon Alpha" USB soundcard.
When i use the soundcard with my AKAI midi controller, i start hearing a background noise. These two devices correctly worked toghether in previous systems, now they are not. I don't know if it's a software related problem...
Thanks in advance.

Can it be a ground loop? That happens when you have more than one device with protective earth connected (in the socket) AND use unbalanced cables (cinch, mono jack). Effects can be a hum and/or hiss, sometimes dependent on mouse movenments.

Solution:
Use balanced cables (best solution if your devices have balanced inputs/outputs) or use an audio transformer.

I placed an USB 4 port hub between the PC and the MIDI controller and i'm having no issues?? How is that possible? Maybe it depends on my laptop?

[bluebell]

Hello guys!
I'm using ubuntu 20.04 with kernel 5.4.0-47 lowlatency and a "Lexicon Alpha" USB soundcard.
When i use the soundcard with my AKAI midi controller, i start hearing a background noise. These two devices correctly worked toghether in previous systems, now they are not. I don't know if it's a software related problem...
Thanks in advance.

Can it be a ground loop? That happens when you have more than one device with protective earth connected (in the socket) AND use unbalanced cables (cinch, mono jack). Effects can be a hum and/or hiss, sometimes dependent on mouse movenments.

Solution:
Use balanced cables (best solution if your devices have balanced inputs/outputs) or use an audio transformer.

I placed an USB 4 port hub between the PC and the MIDI controller and i'm having no issues?? How is that possible? Maybe it depends on my laptop?

If it is a powered hub then maybe the laptop's USB ports didn't have enough power.

[TygerTung]

I find that I have to try and use different USB ports sometimes if I'm getting noise.