How does Frank Zappa get that creamy overdriven electric guitar sound on his Freak Out! album?

How does Frank Zappa get that creamy overdriven electric guitar sound on his Freak Out! album?

 

Comments
David McCain

If I remember correctly, he overdrove the console to get that " square wave " distorted tone ( he plugged his guitar into the recording console and turned the gain all the way up ). Depending on what gear he used and where he recorded, I can't remember exactly.