Can anyone help me find cheap or free DJ sets from the 1970s to buy/download? There are scant few that old on Deep House Page, and other than that I've only managed to find some Italian tapes (by DJs such as Mozart, Baldelli, TBC, Fattori, etc.)

I know that LPs, tapes, etc. of DJ mixes were a popular commodity in the 1970s, especially in the US. So where are all the tapes today?! I need some authentic US disco tapes here people! ;) (Other countries welcomed too except Italy which I've already got tapes from, as mentioned above)

Equally interested (if not more) in '60s and earlier mixtapes as well, although I doubt any exist!