HI ,,,ALL In my first post I mentioned the mod I did to the std F1A4 lower stalk to make it easy to adapt commercial coils ..
I also built a little amp for enhancing the sound , Just a LM386 chip & a few caps & resistors vol pot & boost switch ,powered by a 9v batt ,Housed in an Altoids tin ..can run to speaker & or H/phones works a treat ..there maybe better chips but I had this LM386 in my bits&pieces,spares..
ON the F1A4 the std speaker is awfully quiet ,I removed it & placed an alluminium Disc [Grounded to the coil socket shielding foil-[ie] little black wire] in place of speaker to allow for future switches -pots etc any mods I may come aross
CHEERS ,,, BARRY in SA..