/diy/ - Do It Yourself

I traced part of the pcb from a practice amp because I wanted to find out if I could make it sound better somehow. Now, based on online clips—which I listened to on phone speakers— this amp sounds good-ish when cranked, similar in that aspect to an old vacuum tube amp. Even the "overdrive" channel sounds better with the volume cranked. Otherwise, the overdrive sounds really nasty.
Right off the bat, I think I could increase R3 to a more typical 1Meg and maybe also R8. I could mess around with the feedback resistors and capacitors, maybe replace R7 with a pot for gain control. Swap all the 1uF caps with polyester caps.
One mod suggested online for this amp model is to swap the speaker for a higher quality one. Another is to cut the diodes for higher output and less ugly distortion. Buying a speaker is not feasible right now, and I want to keep the diodes... maybe put them in the feedback loop if possible for soft clipping.

I would like to know:
-Why C1 is oriented that way
-What C28 and C27 are doing
-Anything else that I could do to improve the sound.

I mostly care about fixing the overdrive/clipping stage, but I also want to have more overall high end sparkle from the clean mode.

*I forgot to write the value of C1 and forgot what exactly it is, but I vaguely remember that it's larger than .1 uF.