WOAH! GREAT MINDS THINK ALIKE!
JUST ABOUT 2 DAYS AGO MIKE NICKEL & I WERE EMAILING ABOUT THIS CHALLENGE. I CITED MY ADVENTURES WITH AMPEX PRO AUDIO BEFORE I WAS EMPLOYED THERE. WE ALSO SHARE A ‘CLASSIC’ AUDIO TECHNOLOGY INTEREST, TO PUT IT MILDLY.
CIRCA MID 1970s I WAS FREELANCE, DOING AUDIO RESTORATIONS, MACHINE MODS & REPAIRS, & TRYING TO FIND (OR NOT) A PERMANENT JOB. ALL THAT, & ALREADY WITH A DEAF RIGHT EAR SINCE ABOUT 1953. POOR ME: I’VE NEVER HEARD STEREO. BUT I CAN SEE IT ON A ‘SCOPE (REAL OR DIGITALLY EMULATED) & OR STRIP OF OPTICAL FILM. ONE SUCH EFFORT WAS A FISHING EXPEDITION @ THE RODGERS AND HAMMERSTEIN ARCHIVES OF RECORDED SOUND (LINCOLN CENTER) IN MANHATTAN. THEY WERE SET UP WITH A GAGGLE OF AMPEX 350 SERIES PROFESSIONAL (PLAYBACK ONLY) AUDIO TAPE MACHINES. OSTENSIBLY CREDENTIALED USERS REMOTELY CONTROLLED THEM AT PLAYBACK DESKS IN ITS SPACIOUS REFERENCE ROOM. THE MACHINE ROOMS BELOW HAD ATTENDANTS SPOOLING UP THE OPEN REELS & THEN RUNNING TO THEIR EDIT-ALL SPLICING BLOCKS WHEN THE DISASTERS STRUCK. THEY OCCURRED BECAUSE THE AMPEX DESIGN (DATING BACK TO THEIR DEBUT 20OA IN ’48) EASILY ENABLED, WITH THE TAPES RUNNING IN FAST REWIND & OR FORWARD, SLAMMING THE PINCH ROLLERS AGAINST THE CAPSTANS, WITH THE DOOMED TAPES IN BETWEEN. THIS WAS DUE TO PREMATURE PRESSING (NO SNICKERING PLEASE) OF THE N.C. “STOP” BUTTONS.
TO SOLVE THIS, I USED THE SAME CONCEPT CITED BY DAVE TO DELAY ACTIVATING THE ‘PLAY’ (ALSO RECORD IN FULL FUNCTION VERSIONS) RELAYS TO WHICH I ADDED IN SERIES, “STOP” RELAYS EACH WITH A SUITABLE VALUE CAP. WIRED IN SERIES WITH ITS COIL. THE ABSENCE OF THE ‘MISSING’ RELAY MIGHT & MIGHT NOT HAVE BEEN DUE TO KNOCKING OFF THE DESIGNS OF THE CAPTURED (’45) GERMAN TAPE MACHINES & OR AMPEX REDUCING ITS PRIME MANUFACTURING COSTS. THE FORMER CERTAINLY WAS NOT A MATTER OF PATENTS RIGHTS. THE AMPEX WORK – AROUND WAS THE HARD WIRED LOGIC OF THE CONTACTS OF THE OTHER RELAYS. SORT OF COMPARABLE TO THE IVES – FLYER – LIONEL STUFF?
I DIDN'T THEN KNOW OR NOW RECALL IF I'D YET BEEN AWARE OF THE PRINCIPLE. NOW, IN 2020, IT’S JUST THE DIFFERENCE IN THE SCALES (ANOTHER INTENDED PUN) OF THE NECESSARY COMPONENTS. THE RELAYS & SOLENOIDS IN THOSE MONSTERS OPERATED @150 v.d.c. AND OH, THE SIZES OF THOSE PARTS! THE CONTACT POINTS OF THE 3 POLE RELAYS HAD DIAS. OF ABOUT .25"! AND THINK OF THE RECTIFIER TUBES & THEIR POWER SUPPLIES. THE LATE ‘40s CAPS & FULL WAVE RECTIFIERS OF THE STIPULATED VALUES WOULD'VE BEEN MEGA GARGANTUAN IN THOSE 342 / 343 TENDERS. & WHAT ABOUT THEIR CUMULATIVE WEIGHT?
A FEW DAYS AGO I’D THOUGHT ABOUT TRACKING DOWN (I PROMISE, THIS IS THE LAST PUN…I CAN’T RESIST THEM) A QSI ACRU OR DCRU TO POSSIBLY SOLVE THE ENIGMA. BUT A CAP & A FW RECTIFIER? WHAT COULD BE BETTER? OH YEAH, HANDS NOT SHAKING WHILE TRYING TO SOLDER…
AND WOULDN’T YOU KNOW IT? WITH LIFE GOING ‘FULL CIRCLE’ I STILL GET CALLS FROM THE COUNTRY MUSIC FOUNDATION IN NASHVILLE. I DESIGNED & BUILT ITS RESTORATION LAB AT THAT TIME.
I CAN’T PROOF READ THIS YET AGAIN, SO I’M SIGNING OFF.
SUPER GRATEFULLY,
SHIFFY