Negativland's Super Booper

[Reverend bluE]

If anybody is fairly familiar with Negativland, you may know of the
Weatherman, and his "Super Booper".  I want to make one.  I understand that it
is a feedback loop using an audio amp from an old radio.  If anybody knows of
an easy way to make this, let me know.  I've emailed negativland, but the
Weatherman isn't online, so it may take a while (if Mark Hosler even
remembers..)
thanks in advance...
-ben