help needed for Vox Pathfinder

[Delbro]

I have a SS Pathfinder (newer one) {while I know this is a guitar amp I hope some people here could help}that I am using for the sake of keeping peace in the household- while not anywhere near a tube sound I wanted this amp to be all it can be. Besides replacing the speaker

Problem is Vox /Korg has not answered my request for a schematic for it- and I am tech challenged

So I was going to upgrade parts

and wondered if anyone has one- opened it up
and could identify which crucial resistors & caps [ values & number given to them in circuit]are in the tone path- circuit and gain section

I was planning on putting different IC chips and experimenting with either OPA2134 or LM833, replacing the current JRC4558DD-- the gain sounds a bit more ragged than I like- which I want to smooth out

and also wondered too about the Q1-4 's (tranisters ? ) if
they could be replaced with PNP's or NPN's

any and all help is greatly appreciated--


some may wonder why fiddle with a cheap amp-- it is what I have and again wanted to upgrade