Ritchie Blackmore looping

["Michael Peters" <mp@mpeters.de>]

people told me (and I have found this mentioned online here and there) that
Ritchie Blackmore was an early livelooper, using Revox tape machines. I've
never listened to Deep Purple much so this has completely escaped me so 
far.
Can anyone confirm? when was that, are there recordings or even videos of
this? 

 "Richie Blackmore experimented with it in his early Deep Purple days and
with his previous gigs with 'Screaming Lord Such'. This would have been 
late
60's, early 70's, he's quoted saying people in the audience could see the
reel to reel and would yell at him to 'turn of the tape recorder'"

"Late 60s", so he got into this probably inspired by Terry Riley, before
Fripp/Eno, right?

-Michael