Re; A "clean hi-fi sound".
I remember using my proud Dad's Panasonic Music Centre to play my truly awful "Kay" electric guitar through. By cleverly plugging the guitar jack into a 3.5mm adaptor/reducer, then into the "mic" input on the music centre's cassette tape deck, the pressing the "record" button down, then pressing the "monitor" button in, we could get the music centre to amplify the guitar through the speakers. Result!
The sound was clean...too clean given the crappiness of the guitar, so whacked up the "recording level" on the cassette deck to get a bit of "overdrive" and promptly blew something inside the amp. A hasty disassembly of the rig and a retreat to the bedroom before the old man got home from work. I never did tell him how his music centre got broken.
Another "fix" for not having a guitar amp was removing the wires from a turntable cartridge and sellotaping them to the guitar lead's jack plug. That worked for a wee while too...