i picked up this effect at a garage sale the other day for $10. its a DOD Performer flanger. model number is Flanger 575-A. its got three controls: regen, width and speed. it weights about 5 or so lbs. heres the questions part. it takes (2) 9 vold batteries to power it or a "20 volt D.C., 20 ma, negative power supply" as what is says on the back.the adapter hole is a 1/4'' jack. the serial number is A 033496. could anyone tell me what year it was made and where i could find a 20 volt adapter. it wont use an 18 volt adapter and thats the highest# i could find.