Schematics
Ad N Echo Model 1001 - A freshly drawn schematic of the 7199 circuit.
Ad N Echo Model 3000 - An Ad N Echo with more bells & whistles (12AX7 circuit).
Fender Echo Reverb II - A variation on the 7199 circuit.
Standel Reverbalux - model S41
TelRay Deluxe Organ Tone - Hand drawn trace of a working unit
TelRay Variable Delay - Drawn from 1969 model
