I've slapped three early 70s Zappa shows on a slap up blog page. All crisp SBDs (recording taken from a feed from the soundboard).
El Paso 23rd May 1975
KCET Studio, Los Angeles 6th August 1974
Sydney, Australia 24th June 1973
All primo sound, I promise.
EDIT: Just added Dallas 17th October 1980 and more.
EDIT: and Santa Monica 11th December 1981
Frank Zappa - 76 - Boston Music Hall, 24th October 1976
Frank Zappa - 77 - Palladium, New York 31st October 1977
Frank Zappa - 78 - Deutschlandhalle, Berlin 15th February 1978
Frank Zappa - 79 - Manchester, United Kingdom 12 February 1979