No sound in RetroPie from my Arcade 1 up

[acorn81]

I am VERY new to the Raspberry Pi world and did some research on installing RetroPie to run in my modded arcade 1 up cabinet. I have everything installed and running but I cannot get sound to come out of any speakers I plug into the controller board needed for the mod to the arcade 1 up cab. I have tried with an amp, and powered speakers with a 3.5mm jack

After hours of failed attempts I installed Raspian from the SD card provided with the kit I purchased and sound works perfect from the OS when I watch a youtube video in the cabinet with the powered speakers.

It was my understanding that I could install RetroPie without Raspian but now I am wondering if I am wrong on that lol

When I ran RetroPie (without Raspian installed) I am getting a quick message when booting saying lvl10: VolumeControl::init() - Failed to attach to default card! and of course no sound :(

Am I missing something? Do I need Raspian to run RetroPie correctly? Is there a setting within RetroPie that I need to enable or disable for sound to work properly? I have tried to change the Audio to force through 3.5mm jack in Rasp-Config in RetroPie but that did nothing ?

Any help would be greatly appreciated :)

Thanks

[mitu]

RetroPie is not a standalone OS, the image for the Raspberry Pi it's based on Raspbian Lite, so if your sound works in Raspbian, then it should work in RetroPie.
For the error message you posted (lvl10: VolumeControl::init() - Failed to attach to default card!), try changing the sound settings in Emulationstation - change the Audio device to PCM and restart Emulationstation - see if you get the same error.