[QuadList] Ampex High Speed Dubber and later VHS systems

[Pat Shevlin]

Hi Mark,

 

Good to hear that you are still out there.  Thanks for giving the group a
well detailed explanation on the history of high speed duplication.

 

The best,

Pat

 

Pat Shevlin

Director of Technology

 

The Media Preserve

"An Audio Visual Laboratory"

A Division of:

Preservation Technologies, L.P.

800-416-2665

724-779-2111

 <mailto:pshevlin at themediapreserve.com> pshevlin at themediapreserve.com

 <http://www.themediapreserve.com> www.themediapreserve.com

 

 

  _____  

From: quadlist-bounces at quadvideotapegroup.com
[mailto:quadlist-bounces at quadvideotapegroup.com] On Behalf Of Mark Anzicek
Sent: Thursday, March 11, 2010 2:42 AM
To: Chill315 at aol.com; quadlist at quadvideotapegroup.com
Subject: Re: [QuadList] Ampex High Speed Dubber and later VHS systems

 

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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