pulseaudio – no sound after the upgrade to B450 Tomahawk on 18.04

I was / are using Ubuntu 18.04 (an upgrade of at least 2 previous LTS versions, if that matters). Everything worked, even sound.

I've just upgraded the motherboard to a B450 Tomahawk (Ryzen 5 2600x). Now the sound does not work anymore. I have speakers in the "line out" system behind the motherboard and the headphones in front, there is also no sound from testing. I think that must be a driver / module problem – probably.

I tried killing Pulseaudio and removing ~ / .config / pulse / * and ~ / .pulse *, then rebooting … still does not work.

lspci shows this for audio:

1c: 00.1 Audio Device: NVIDIA Corporation GK107 HDMI Audio Controller (Version A1)
1e: 00.3 Audio Device: Advanced Micro Devices, Inc. [AMD] Family 17h (models 00h-0fh) HD audio controller

I think the second is what I need. Looking at lsmod, I see:

snd_hda_codec_hdmi 49152 1
snd_hda_codec_realtek 106496 1
snd_hda_codec_generic 73728 1 snd_hda_codec_realtek
snd_hda_intel 40960 3
snd_hda_codec 126976 4 snd_hda_codec_generic, snd_hda_codec_hdmi, snd_hda_intel, snd_hda_codec_realtek
snd_hda_core 81920 5 snd_hda_codec_generic, snd_hda_codec_hdmi, snd_hda_intel, snd_hda_codec, snd_hda_codec_realtek
snd_hwdep 20480 1 snd_hda_codec
snd_pcm 98304 4 snd_hda_codec_hdmi, snd_hda_intel, snd_hda_codec, snd_hda_core
snd_seq_midi 16384 0
snd_seq_midi_event 16384 1 snd_seq_midi
snd_rawmidi 32768 1 snd_seq_midi
snd_seq 65536 2 snd_seq_midi, snd_seq_midi_event
snd_seq_device 16384 3 snd_seq, snd_seq_midi, snd_rawmidi
snd_timer 32768 2 snd_seq, snd_pcm
snd_hda_codec_generic, snd_seq, snd_seq_device, snd_hda_codec_hdmi, snd_hwdep, snd_hda_intel, snd_hda_codec, snd_hda_codec_realtek, snd 81920
soundcore 16384 1 snd

I think it should first find the generic device, which should cause it to use the Realtek device. "Aplay -l" to do, gives me:

**** List of PLAY hardware devices ****
Card 0: NVidia [HDA NVidia]Device 3: HDMI 0 [HDMI 0]
  Subdevices: 1/1
Sub-device # 0: sub-device # 0
Card 0: NVidia [HDA NVidia]Device 7: HDMI 1 [HDMI 1]
  Subdevices: 1/1
Sub-device # 0: sub-device # 0
Card 0: NVidia [HDA NVidia]Device 8: HDMI 2 [HDMI 2]
  Subdevices: 1/1
Sub-device # 0: sub-device # 0
Card 1: generic [HD-Audio Generic]Device 0: ALC892 Analog [ALC892 Analog]
  Subdevices: 1/1
Sub-device # 0: sub-device # 0

So generic is an ALC892 that I can read that others have done. To access KDE's "System Settings" -> Mutlimedia -> AudioVolume -> Advanced, I switched off the GK107 HDMI and I set "Family 17h HD Audio Controller" to "Analog Stereo Output" (I also tried "Analogue" Stereo Duplex "), but I still get no sound – tried with aplay and qmmp.

What else can I search for or do to solve this?
Would it really have to be reinstalled to recognize everything correctly?

Suggestions very appreciated. 🙂