Oldskool trance techno track sampled by Digitalism

Hi

Please take a listen to the first 15 seconds of this Digitalism tack, called "Circles", off their second album.

It samples a trance record from 1992 / 1993 but I can't put my finger on it. I thought it was Eternal Spirit by 4Voice (Pete Namlook) and it does sound similar, but I think there's something even closer, perhaps less well known than anything by Namlook.

Here's a youtube link.

Digitalism - Circles - YouTube

If you know what it samples (rips off) please let me know!

Cheers,
SCARAMANGA