A very early Electrix Mistress, deluxe.
I think this dates from 1978.
This uses the SAD 1024 Bucket Brigade chip.
The EHX Delux mistress is a early flanger.
Les Paul in 1945 ??
They originally used two tape recorders ... one running slightly out of sync / slower than the other.
From what I've read, the first flanger using an bucket brigade delay ICs was the Eventide instant flanger FL201 in 1976 This beauty had CV controls that allowed modulation of the effects using modular synths.
The Eventide used two Panasonic MN3001s clocked at 2.7 MHz.
The PCB is labelled EH1318 A which makes it a Version 1 from 1978.
Notice the curled knob with pointer.
with one transistor ... a 2N5087.
+ Metzgerralf - V1 pics
+ How the Flanger works - detailed
+ Reverb - Eventide FL201