audio not outputting to headphones & audio corruption

[Michael Haworth]

Description: Ubuntu Focal Fossa (development branch)
Release: 20.04

At first sound was working through the inbuilt speakers, but when plugging in headphones (which I know work) no sound is output. I unplugged the headphones but no sound is output from speakers either. I found that the sound returns after stopping playback and starting after a minute or so, sound plays normally for a few seconds but then sounds garbled thereafter.

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: alsa-base 1.0.25+dfsg-0ubuntu5
ProcVersionSignature: Ubuntu 5.4.0-18.22-generic 5.4.24
Uname: Linux 5.4.0-18-generic x86_64
NonfreeKernelModules: nvidia_modeset nvidia
ApportVersion: 2.20.11-0ubuntu21
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC1: bailtree 1337 F.... pulseaudio
 /dev/snd/controlC0: bailtree 1337 F.... pulseaudio
CurrentDesktop: XFCE
Date: Thu Apr 2 09:29:24 2020
InstallationDate: Installed on 2020-03-25 (8 days ago)
InstallationMedia: Xubuntu 20.04 LTS "Focal Fossa" - Alpha amd64 (20200325)
PackageArchitecture: all
SourcePackage: alsa-driver
Symptom: audio
Symptom_AlsaPlaybackTest: ALSA playback test through plughw:PCH failed
Symptom_Card: Built-in Audio - HDA Intel PCH
Symptom_Jack: Black Headphone Out, Left
Symptom_Type: Only some of outputs are working
Title: [hostname, Realtek ALC295, Black Headphone Out, Left] Playback problem
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 07/09/2019
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: GX501VIK.311
dmi.board.asset.tag: ATN12345678901234567
dmi.board.name: GX501VIK
dmi.board.vendor: ASUSTeK COMPUTER INC.
dmi.board.version: 1.0
dmi.chassis.asset.tag: No Asset Tag
dmi.chassis.type: 10
dmi.chassis.vendor: ASUSTeK COMPUTER INC.
dmi.chassis.version: 1.0
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrGX501VIK.311:bd07/09/2019:svnASUSTeKCOMPUTERINC.:pnGX501VIK:pvr1.0:rvnASUSTeKCOMPUTERINC.:rnGX501VIK:rvr1.0:cvnASUSTeKCOMPUTERINC.:ct10:cvr1.0:
dmi.product.family: ROG
dmi.product.name: GX501VIK
dmi.product.version: 1.0
dmi.sys.vendor: ASUSTeK COMPUTER INC.