bit of a tale with my Solo C350/SRe-12. It developed a strong dissonance ((distortion) on a couple of notes - F# and A played on the lower (E A D) strings and particularly ‘up the fingerboard’. Normally I’d fix it myself but the guitar was sold to me as new with full warranty, all be it that it was a 2013 model - so NOS. I noticed on trying it ‘plugged in’ in the store the jack was hard to pull outa the jack socket, like real tight. On having it for a few weeks and plugging it in at home and out at my ‘open mic / jam’ night I noticed it getting worse so did some fault finding. My initial thoughts when hearing these loud distortions were - Oh no - it’s ’structural’ - a loose brace or truss rod ‘rattle’ and the like - not a good feeling. Turned out to be the jack sock / battery holder at the tail end had come loose - due to the excessive force needed to extract the jack, the 3 little retaining wood screws holding the plastic housing had been loosened (stripped the thread in the end block) allowing it to vibrate. The distortion ceased when I held the jack / battery holder, the screws are to short / small to securely hold the unit in place - with the socket being that tight on the jack. I took it back to the store which has an in house ’Tech’, now this is where it gets entertaining (for myself) dealing with store assistants / technical staff. I outlined the issues described above to the Tech and I was told - “oh no - it won’t be that, it’s usually the ‘wires’ touching something inside”, dissing my observations, like - your a customer - (and a senior citizen) what would you know. Sorry to ramble on but just to warn folks to this issue (on any guitar) with this kinda setup, as it’s something I’ve never come across before. Got it back ’n the tech said he’d checked the wiring and found a wiring tie stuck to one of the braces - that was the problem !! - somehow I don’t think so. He also said he’d tighten the screws in the jack / battery holder but did’nt splay / open the overly tight jack connectors to reduce the ‘grip’ on the jack. All in all I can see myself replacing the wood screws and opening the connectors. Thankfully I still have faith and trust in my garage to keep me safely ‘on the road’.