I've always wondered how Jan (prounounced yahn right?) Hammer got those crazy Ring Modulator sounds on his Rhodes in the Mahavishnu Orchestra. Do Rhodes have that option on them or what?

I'm 99.9% sure it was an effects unit. I SAW Mahavishnu Orchester on the Birds of Fire tour when I was in Jr. High School in my then home town of Lowell MA. (USA) in the deep dark 70s. Now THAT was an eye opening concert!!!! A musically RELIGIOUS experience!

Huge Mahavishnu fan Here! Never got to see them. Would have been Jr High for me too.
I don't know what Jan was using exactly. This is probably close.

http://www.moogmusic.com/detail.php?main_product_id=6 i

I am sure this is very close to the circuit used in the Moog modulars, and the Mini Moog.
Expensive, but pure analog and American made.

There are also some videos on you tube, Jan sometimes left the top of the Rhodes off and dampened the strings of certain notes as he played.

My favorite Jan Hammer album was finally released on CD after 30 years! Jan did the remix and remaster himself. It sounds awsome.

http://www.amazon.com/Oh-Yeah-Jan-Hamme ... 163&sr=1-1

Oh Yeah!, Lee