This is what the MuRF was based on.

The Moog Forum Moogerfooger Forum
1

I’ve been looking for this for some time now.

The Murf was based on a design from the Formula Sound Multiple Resonance
Filter Array:

http://home.att.net/~elhardt/Formula_Sound_String_Filter.jpg

It was designed by a man called Patrick Gleeson in the 70’s

Very interesting…

2

Good job finding the thing. The Murf even has the same kind of slider knobs.

3

I love the Moog MuRF and it’s cool that MoogMusic brought this strange processor back from the grave.

4

Moog Custom Engineering back in the 70s made a string filter with multiple resonant filter banks, I don’t remember how many somewhere between 24 and 40 banks. http://www.modusonics.com (Mike Bucki’s business, who used to work at Moog CE) stills makes them.

The concept of multiple resonant banks goes back a few decades. I vaguely remember a discussion on SynthDIY on them.

5

Wasn’t the String Filter built by Harold Bode who made the Frequency Shifter?

6

Nope, Bode did not design/build the string filter.