I have earlier stuff than this, but only on cassette. First recordings are from 1989, but these are the earliest I could find digitally. I have a lot of stuff from this era (early to mid 90s).
"Red Ampersand," spontaneous improv recorded to cassette 4 track with 1 mic, 1993:
"Psychedelic Emergency," recorded in my parents' basement when I was house-sitting for them, summer 1992. This is me and my best friend to this day:
This was a LONG time ago.