connecting a microphone via USB

[tad]

Dear Armin,

I appreciate your detail investigations!

I haven't installed alsa driver tools so that I executed them as as follows:
"apt install -y alsa-oss alsa-tools alsa-tools-gui alsa-utils alsamixergui mpg123"

I rebooted the netPI and check the phenomenon again.
After the reboot, I typed as follows.
The result was the same as before installing alsa driver tools.

root@raspberrypi:/# lsusb
Bus 001 Device 004: ID 0c76:161f JMTek, LLC.
Bus 001 Device 003: ID 0424:ec00 Standard Microsystems Corp. SMSC9512/9514 Fast Ethernet Adapter
Bus 001 Device 002: ID 0424:9514 Standard Microsystems Corp. SMC9514 Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
root@raspberrypi:/# arecord -l
**** List of CAPTURE Hardware Devices ****
root@raspberrypi:/# apt install -y alsa-oss alsa-tools alsa-tools-gui alsa-utils alsamixergui mpg123
Reading package lists... Done
Building dependency tree
Reading state information... Done
alsa-oss is already the newest version (1.1.8-1).
alsa-tools is already the newest version (1.1.7-1).
alsa-tools-gui is already the newest version (1.1.7-1).
alsa-utils is already the newest version (1.1.8-2).
alsamixergui is already the newest version (0.9.0rc2-1-10).
mpg123 is already the newest version (1.25.10-2).
0 upgraded, 0 newly installed, 0 to remove and 38 not upgraded.
root@raspberrypi:/# arecord -l
**** List of CAPTURE Hardware Devices ****
root@raspberrypi:/#

And, the attached 'mytrace.txt' in my previous post was collected from netPI.
I will come back here when the trace is got from a commercial raspberry pi.

Best regards,