Well... Yes what is Obscure Disco?
That question can be hard to answer but I'll sure give it a try and I'll give you my point of view...

I would say that Obscure Disco music is great Disco songs that never made it into the charts. That's a little rough explanation but I'll explain more if you read on...
The "Chart Disco Hits" are more of a "mainstream" Disco type of songs, while the obscure tracks are the ones often just heard in clubs or in special mix-shows on Disco radio stations. These songs never got the attention as the "mainstream" and often more easy-listened Chart Disco.
Personally I love all types of Disco music, but these days I guess I more and more try to find my these Obscure tracks most people don't know of or haven't even heard before.

Part of the reason why some great Disco tunes are Obscure, is probably because most of them were released on small labels. Labels which sometimes just released one or just a few records. These records wasn't pressed in anywhere near the same quantity as the big hits.
Also... Most of the song that became hits was usually released on some of the major labels like; Atlantic, Casablanca, Columbia and Salsoul.
But some classic big Disco labels that released many obscure tracks was Prelude and Westend.
These two were quite big labels, but there was soo many small ones as well. You should keep in mind that during the Disco era there was soo many records released. Everybody wanted to release a Disco hit, there was lots of good stuff but also lots and lots of really bad stuff.

So... Now you're wondering... Give me an example on a Obscure Disco tune. Often these Obscure tracks are instrumental Disco orgies or sometimes it's an instrumental version of a less successful vocal track. This was the case with for example Francine McGhee's "Feelin' good", this vocal track was really bad while the instrumental flip side of the 12" single - "Delirium" is a very sought for and awesome Obscure Disco track.
Another kind of Obscure tune is actually Tamiko Jones' "Can't live without your love". This was released on Polydor, but that shows that even the major labels could release som Obscure tracks. But there are soo many Obscure songs and acts that I could go on listing them forever... But some acts to look out for are; THP Orchestra, Constallation Orch., Saturday Night Band and Norma Jean (ex-vocalist of Chic) just to mention a few.

If you hear all the new songs with all the samples they use you can find two different types of "sample users". Many artists choose to use the well-known Disco classics (the Chart hits) to sample in their songs. That way people recognize the samples quite easily, but then there's the other type of "sample users" the artists who wants to find hooks or other special parts of Obscure tracks to sample. A example of that is the Mighty Dub Cats song "It's just another groove" in which they sampled the Patrick Adams act Cloud One's Obscure Disco track - "Disco Juice".

I hope you've got some idea of what a Obscure Disco track might be. There's really so much more to Disco than the "Chart Hits".
'Till next month...

Take care and Disco-on,