[QuadList] Ampex High Speed Dubber and later VHS systems

[Mark Anzicek]

Chris,
I'm not sure how this will post.  It's my first time. This may be quite
a bit more than a comment on high-speed dubbers, so please excuse me if
I have provided too much information.
Mark Anzicek
ZenTechnologies
 
We, as engineers at NET,  were told that only 3 Ampex ADR-150
duplicators were ever built.  One was in LA.  We had one at NET in Ann
Arbor and it was rumored that there was one in an airplane hanger in
Saudi Arabia that was never assembled.  However NET's unit was the only
6 copy station unit in existence. The other two were 2 copy station
units.  Everyday we high-speed duplicated 100 to 200  Quad 2" video tape
copies of Sesame Street, along with other shows including NET playhouse,
Monty Python, Faulty Towers.....etc.  Our ADR-150 duplicated qty 6 one
hour Quad 2" video tapes in 6 minutes.  
 
Like a photographic processing, high-speed video duplication is
basically a printing process except instead of light passing through a
negative onto a paper, a 700 to 800 oersted blank tape and a 2400-2600
orested high energy master are in intimate contact and passing through
an high energy field that is strong enough to provide an erase bias for
the copy tape, but not enough to degrade the master the master due to
the tremendous bias need for a 2600 orested tape.  Traveling out of the
bias field, at 150 IPS, the copy tape would be immediately cloned by the
master in a direct magnetization transfer printing process as the master
pressed each copy tape around each individual slave copy drum at 6
different points simultaneously along the master path.  
 
As Chris Hill said, a specially modified AVR-1 was used to make the high
energy mirror masters as they were called.  NET had 2 stock AVR-1s in
house and either one could be quickly switched over to make high speed
masters.  The change consisted of exchanging out the bias erase head,
corresponding driver circuit board and the same for the video head.
Both heads and circuitry were beefed up to handle the extra bias and
record energy needed.  The erase stack had to be liquid cooled and Spin
Physics modified the video heads to spin in reverse, hence being able to
create a mirror image.  The left to right master prints right to left
copy.
 
A high-speed 10x transferred copy tape was about 3db down from a perfect
real-time duplicated copy, however it's uniformity and almost perfect
interchange statistically yielded more acceptable copies than the up to
50 or so individual VTRs needed to produce the same amount of production
capacity. (depends upon how fast operator can switch out tapes) The
masters could theoretically last forever, as far as energy levels
needed, however in time the master would become dirty and loose intimate
contact, yielding further gradual signal db loss.  Many masters were
recorded over and used again as different program masters.  Many times,
masters would catastrophically fail before their average number of uses
would cause failure. Once a tape became wrinkled or creased, it could no
longer be used.  It could be shortened to a shorter master length, but
only if the crease was close to either end of the tape.  It had to be
that much shorter.  Many real-time Quad tapes were spliced, due to the
almost perpendicular head path, but the ADR-150 had extremely low
thickness tolerances so splices meant certain death of a master or copy.
 
Our ADR-150 was about 25 ft long by 6 ft wide by 3 ft high.  The master
would run down one side of the machine, past 3 slave copy stations, then
return back passing another 3 stations on it's way back to the master
station take-up reel.  Each of the 6 copy stations had 4 AVR-1 type
vacuum columns yielding 24 Air vacuum chambers to buffer the movements
of 6 individual copy tapes in intimate contact with a master at 6
different 10" rotating copy drums along the master tape path.  Each copy
drum had 2 separate air knives along a drum collar to assure intimate
contact. along 270 degrees of the rotating drum.  The master would then
automatically rewind while the operator changed out the 6 copy stations
with more tapes and then re-started the process.
 
Yes indeed, I loved to run and work on that machine except for the fact
that you had to wear earmuffs because it sounded like you were on the
tarmac of an international airport.  IT WAS VERY LOUD !!!!   It blew and
sucked more air than anything I've ever worked.  Extreme care had to be
given to operating and maintaining this electromechanical beast.  If any
one of the numerous servos fell out of balance, as the 6 slaves chased
the master traveling 12.5 ft/sec (8.5 mph), or any moisture entered the
system, or any vacuum loss in any one of the 24 columns, or any over
pinching of the air knives, there would be a traveling pileup of tape
loops and creased tape.  The operator would witness something like a
chain reaction of car accidents traveling first down the highway, then
turning around and traveling back up the highway.
 
In the 1980s, Sony manufactured a high-speed 1/2 duplicator called the
Sprinter 5000.  (S-printer)  It was first designed for Beta and then
Sony sadly converted it to VHS. This machine had just one station and
ran at 16.6 ft/sec.  Later, a new model 800 was introduced with a
endless master loop that vibrated on a horizontal loop bin, much like
those vibrating football game tables of the 1050s. It's speed was then
almost doubled to 8 meters/sec and it's effective duplication speed was
increased to almost 240x for SP and 720x for EP VHS.   I built a
facility for Allied Film & Video in the 1980s that housed 16 of these
machines and also developed an endless master bin for the first 5000
Sprinter.
 
In the late 1980s, Otari took over a joint research project started by
Dupont and Bell & Howell to develop the TMD. (Thermo Magnetic
Duplicator)  Dupont wanted to sell chromium and Bell & Howell owned
several large VHS duplication facilities in Chicago at the time.  They
later became Rank and moved much of the operations to Little Rock, AR.
The technology was similar in mechanics and magnetic printing process,
however instead of using a bias field to erase iron tape, a laser was
used to heat chrome tape to Curie point and erase the tape.  Chrome tape
needed a much lower temperature to accomplish this and the quality was
quite good.  Otari had 2 problems besides being late in the game.
Chrome tape was more expensive and their loop bin was vertical instead
of horizontal.  This meant the weight of longer movie masters meaning
more tape could crease the tape, where as horizontal loop bins didn't
have this problem.  However, by the time Otari had a competitive product
out in the field, Sony had almost saturated the VHS high-speed
duplication business as VHS was reaching maturity.
 
While Bell & Howell started as the largest duplicator, Technicolor later
became the largest US and then worldly duplicator.  Both companies
started with 10s of thousands of real-time duplicators.  B&H/Rank first
implemented 2x machines using large pancakes of blank tape that were
later cut into separate video cassettes like Sprinters and TMDs.  Then
Panasonic made a 2X in cassette duplicator especially for Rank then
later other smaller competitors and Technicolor later introduced their
own 3x in cassette duplicator.  Cinram followed as well with a 2x in
house design.  
 
Technicolor became the king with the most Sprinter duplicators boasting
around 80 unites between Livonia, MI and Camarillo, CA and more around
the world.  The largest Sprinter installation ever was a facility I
designed and built in Alphaville, Brazil in suburban Sao Paulo, where
Videolar had over 100 Sprinters in one very large clean room.
High-speed duplication at one time was at least 50% of the movie
business of which probably 80 to 90% was Sony's Sprinter.  Oh yes, all
good high speed operations were typically conducted in class 1,000 or
better rooms.  As time went on, the vendors advertised class 10,000 in
order to sell more product.  You need massive amounts of properly
directed air flow  (we had 3 air changes per minute) and lots of 0.1 to
0. 5 micron HEPA filters.  
 
Finally, let's talk about cleanliness in Quad vs. VHS when it come to
high-speed duplication.  As you know, it is a contact printing
technology so cleanliness affects transfer quality.  One second of Quad
time represent 2" times 15" per sec. tape speed yielding 30 square
inches of magnetic information describing 1 second of video.  Whereas 1
second of VHS tape time represents 1/2" times 1.3" per sec. tape speed
yielding 0.65 square inches of magnetic information describing 1 second
of VHS SP.  AND one 1/3 that or less than 0.22 square inches of tape for
VHS EP.  Cleanliness and intimate contact are far more important when
you have around 1/50th and 1/150th  respectively less real estate to
work with.
 
 
-----Original Message-----
From: Chill315 at aol.com [mailto:Chill315 at aol.com] 
Sent: Wednesday, March 10, 2010 8:39 AM
To: quadlist at quadvideotapegroup.com
Cc: markanzicek at comcast.net
Subject: Re: [QuadList] Ampex High Speed Dubber




NET in Ann Arbor had one of the handful of Ampex High Speed dubbers.
The master was a mirror image that was done on a AVR 1 with special
heads.  The tape was a special formulation that 3 M did with an orested
of about 3000 (?).  This would allow the magnetic information to be
transferred in special stations.  The machine was very fast and they
never seemed to have any quality issues.  
 
when the building caught fire it was the end of an era.  I have copied
an expert on this machine to see if he wishes to comment.
 
Chris Hill
WA8IGN

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