V/A - An Anthology of Noise and Electronic Music Vol. 1, Sub Rosa, 2002 (1921-2001)

This is the first in a series of volumes released by Sub Rosa in an attempt to map out the history of electronic music in the 20th century, much like the OHM+ box set but this one came out a little earlier, I believe. This is the only volume that has not been reissued, and so copies are scarce and go for hundreds of dollars already. It's got some good stuff on it and even if you're already really familiar with the history of early electronic/noise music it's still very valuable, as it has many unreleased pieces that aren't found anywhere else. The actual CD comes with an extensive booklet detailing each piece and so if you ever find this for a decent price it's a good idea to snag it while you can. Includes unreleased tracks by Luigi Russolo, the Dream Syndicate, Einsturzende Neubauten, Sonic Youth, John Cage, Ryoji Ikeda and others. I personally find the comp invaluable for the Walter Ruttman track alone: it's an unreleased track, originally compiled in 1930 of, by his definition, a "silent film", which was originally played in a theatre in which the audience watched a blank movie screen the entire time; it predates many later works by Cage, Schaeffer and others. Here's the full Tracklisting:

Disc 1
Luigi Russolo and Antonio Russolo - Corale (1921) (1:57)
Walter Ruttman - Wochende (1930) (11:17)
Pierre Schaeffer - Cinq Etudes de Bruits: Etude Violette (1948) (3:18)
Henri Pousseur - Scambi (1957) (6:27)
Gordon Mumma - The Dresden Interleaf 13 February 1945 (1965) (12:43)
Angus MacLise, Tony Conrad and John Cale - Trance #2 (1965) (5:07)
Philip Jeck, Otomo Yoshihide and Martin Tétreault - Untitled #1 (2000) (6:06)
Survival Research Laboratories - October 24, 1992 Graz, Austria (1992) (6:11)
Einsturzende Neubauten - Ragout: Küchen Rezpt von Einsturzende Neubauten (1998) (4:08)
Konrad Boehmer - Aspekt (1966) (15:13)

Disc 2
Nam June Paik - Hommage à John Cage (158-59) (4:13)
John Cage - Rozart Mix (1965) (7:18)
Sonic Youth - Audience (1983) (6:00)
Edgard Varèse - Poeme Electronique (1957-58) (8:00)
Iannis Xenakis - Concret PH (1958) (4:40)
Paul D. Miller aka DJ Spooky (That Subliminal Kid) - FTP>Bundle / Conduit 23 (2001) (8:07)
Pauline Oliveros - A Little Noise in the System (Moog System) (1966) (30: 16)
Ryoji Ikeda - One Minute (1997) (1:00)

Download here and here