I was plugging my guitar amp headphone output into RIP and for a brief moment audio was being sent via TS cable into the headphone output (because I neglected to plug in a dummy cable to RIPs B channel). Now the left side on my amps headphone output is busted (right side is fine, again it was a TS cable so only the tip was carrying audio).
It’s a cheap 80s solid state amp (dean markley, 20w I believe), but it looks like it’d be a nightmare to open up, not even sure where to begin lol. Is it even worth doing? Does this seem like something repairable or is this likely a replace-the-part situation? I tried googling but it seems like sending audio into one half of the headphone channel is maybe a bit unusual as far as idiotic things to do go 
(Earlier today I repaired my electric guitar which has been busted for 10 years because I now know that grounding is a thing, so I am slowly learning things. Sorry for asking so many silly DIY questions on here recently but I promise I’m working at improving lol
and am doing independent research as well)