One of the first real breakthroughs I had after joining SoundCloud was stumbling upon a user called R_co, who, instead of posting their own creations (at the time the platform was mostly used for dance music and DJ mixes, although its user base has since expanded), would upload entire sets by other DJs. A lot of them were contemporary German techno types whom I wasn't particularly grabbed by, but interspersed throughout were ones by the DJs who more or less invented deejaying as we know it. Vintage sets by the likes of Ron Hardy, Frankie Knuckles, and Larry Levan from dance meccas like the Music Box and Paradise Garage would pop up regularly with no indication of how R_co got their hands on them and where they came from in the first place. It was almost unreal—the recordings captured the period of time when these DJs were proactively evolving disco into what would come to be known as house music, and as such they're extremely valuable documents. They were also the type of thing that even die-hard dance-music fans had mostly heard of but never actually heard, and here they were being released on a steady basis, for free.

Recently I was already deep into a R_co rabbit hole that I dug while working on a review of a new Frankie Knuckles mix when Reader digital content editor Tal Rosenberg hit me up on Gchat and ordered me to stop whatever I was doing and listen to a 1974 mixtape that pioneering disco DJ, producer, and all-around behind-the-scenes guy Tom Moulton had made for the Sandpiper nightclub on Fire Island. For dance-music historians it was like finding out that someone had posted photos of the One True Grail on their Tumblr.

Needless to say it's a fantastic mix, superdeep and organically funky. Moulton got his start in the record biz at the King label, where James Brown spent the early years of his career, and he helped introduce ideas like extended remixes, 12-inch singles, and beat-blended DJ sets that would form the foundations of dance music's machine-assisted near future.

If you're having a party this weekend maybe you should just consider at some point switching over from your iTunes "PAR-TAY TIME" playlist and give this a spin.

If you want to get deeper into Tom Moulton, NPR has this great profile/interview by Michaelangelo Matos (you can also try to track down Soul Jazz's excellent compilation from 2006, though import prices on Amazon are currently going for upwards of $70). And if you want to know more about the mysterious R_co (spoiler alert: he's not a pro DJ, just an extremely enthusiastic German techno fan) you can check out this brief but entertaining interview.