From a listServ post found via Wikipedia, The writer is John Kilgore:
Back in the dark ages when I was a young whippersnapper of an apprentice
engineer, I worked in a studio (Apostolic) where Frank Zappa made four
albums (We're Only in it for the Money, Lumpy Gravy, Reuben and the Jets
and Uncle Meat). When Frank was building ...Money, we used this thing
called the Apostolic Blurch Injector. Frank would fill up the Scully 12
track with snippets of his old abums (varispeeded, of course), interviews
with guys who were trying to get him to drop acid (Frank's only vices were
Coffee, Kools and CocaCola), chopped up snippets of stuff the censors
wouldn't let him use (no kidding - and this was 1968) and mics planted to
catch what the cops said when they came to bust us in the middle of the
night cause we were keeping the neighbors awake. All of this would be mixed
down to a single track and put on a new fresh 12 track tape which he would
fill up with these collage tracks. The Blurch injector was a keybord made
up of twelve switches which were patched in line between the 12 track
outputs and the console. Then he would play the 12 track, which he called
the BROWN NOISE master, and wail away on the keyboard. This is how he made,
in part, Nasal Retentive Calliope Music an other stuff of that ilk.
A much cruder version of this concept is Leon and Brian Dewan's home-built synthesizer/mixer hooked up to three vintage 8-track players. [photo] [link]. Undoubtedly many others have done some variation on this pre-digital or non-digital way of manipulating sound. Possibly one thing that made Zappa's work so compelling and dynamic was the use of top-of-the-line studio gear and recordings. Unlike the various basement producers, he got in there and used the Suits' equipment, guerrilla fashion (because they thought he was going to produce a hit album).