[QuadList] Ampex High Speed Dubber and later VHS systems

Thu Mar 11 23:38:50 CST 2010

Thank you Dennis Degan for noting the ADR-150 in NY.  I probably mixed
up the Editel LA facility with Editel NY.  The machine you saw was
probably a 4 slave unit.  ADRs only came in even numbers of slave
stations.  You might have seen the master station and thought it was a
5th slave station. The ADR-150 was modular.  It had 1 master module
station with supply and take-up reels and vacuum columns.  Each
successive module next to it was made up of dual slave stations with one
slave on each side of the module, hence the master would travel down one
side and back the other side.  It could only be configured in groups of
2 slave stations.

I'm scrambling to look for pictures of the ADR-150 and will try to
provide some.  I think I have service manuals for both Sony 5000 and 800
Sprinter models along with some MMR(mirror mother recorder) manuals.
Sony forced you to buy a mastering machine for each format and each
speed and they started at about $135,000 each.  Sony made a SP MMR and
an EP MMR for NTSC.  Michael Sterling, who later ended up at
Technicolor, modified I believe a SP MMR to make make LP masters.  Sony
later released a similar design. It was a nice compromise because it
could save tape cost, have very very good interchange and treat the
linear audio a little better, or at least it was twice the speed of the
11mm (0.43") per sec of EP.  European VHS was a little simpler, in that
Sony only had one MMR machine.  They only accepted the faster speed and
because PAL & SECAM were esentually the same,
except for color coding, a couple circuit boards were changed to convert
the machine between PAL and SECAM.

Otari originally did have Ikegammi make their MMR machines which could
switch between formats.  Later, Otari made their own mirror mother
recorders.  

Buy the way, the only MMR machine motor that was reversed was the head
motor, whether it was Quad or helical VHS/Beta.    A statement was made
earlier about playing a tape backwards on an AVR-1.  I have seen this
happen several times at NET, but it wasn't because the machine was set
up as a master maker.  It would playbackwards because it was mistakenly
threaded onto the machine tails out.  Not only did it play backwards,
the video was also upside down because the tape was upside down. The
AVR-1 was capable of locking up to sync in 200ms or less.  It didn't
need CTL.  It was that good.  It locked up by trying to peak the RF
envelope.  So if you played it tails out, the audio was a sputtering
noise track because it was reversed (top to bottom) and now playing the
CTL as audio AND the video was upside down.  The slight Quad slant was
reversed, so the RF wasn't ideal, but it did play.  The AVR-1 had the
only analog time base corrector that I'm aware of.  Even many Sony
people quietly admited it was the best TBC ever made.  Video delay was
corrected by the use of several glass delay lines.

I'm not sure I've ever seen a regular tape play on a master making
configured AVR-1 or any 1/2" format master machine.  If it did, it would
not play it backwards.  If it played it at all, it would play it upside
down, but not backwards unless it too was mistakenly threaded tails out.
An AVR-1 could be switched from regular to MMR in less than 5 minutes. I
don't think there is any possibilty of playback when using a MMR for
1/2" because the tracks are helical.  The slant difference between Quad
and helical is extreme.  Quad is like a lower case l ever so slightly
leaning to the left or to the right, whereas in helical it's more like a
maily horizontal / vs \ yielding no video signal recovery except for
possibly 10% of the center portion of the screen which would be upside
down.

The HiFi audio by the way was transferred along with the video in the
same area of the tape.  We used to develop the master tape with
Ferrofluidic fluid, then look at the traces with a microscope to make
sure head alignments of video and hifi audio tracks were dead nuts on
top of each other.  This assured perfect interchange tracking and
synchronized peaking of maximum audio and video signal simulataneously.
This was xtremely important in VHS EP.

Chris asked about CTL and linear audio tracks.  If I remember correctly,
magnetic transfer printing works well at higher frequencies and terrible
at lower frequencies.  The tips of the CTL would transfer well because
they were high frequency spikes of the square wave transistions, but the
lower frequency differentiated part of the wave would not transfer well.
For that reason, a triple head stack was used to detect the spike for
synchronization and then rerecord the CTL downstream at a perfect
multiple of CTL distances further down the tape path.  It was set for SP
CTL wavelength distances so it could handle both SP and EP, with EP
spacing being 3 times shorter.  1/2" systems also need the addition of a
cue track which was recoded on top of the Audio and Video RF with a
stationary head.  This was needed to tell the cassette loaders where to
cut and splice the tape into the video cassette.  Every 1/2" high speed
dub ever made had about 30 seconds of really bad video white noise at
the very end of the tape.  That was the control track.

I just looked at a block diagram in the Sprinter 800 service manual and
it confirmed what I thought, but was not certain of until now.  It shows
cue and CTL heads and circuitry, but no linear audio heads or audio
circuitry.  That means that the linear audio was also transferred in the
magnetic printing process and I believe the same with TMD.  I'm not sure
that was the case with the Quad ADR-150 though.  I don't have an ADR-150
manual.  I do want to say though, that in the back of my head, I
remember seeing audio board in each slave station.  It's been so long
and I can't remember for sure.

OK - I promise - That's it - enough said
Mark Anzicek
ZenTechnologies  

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Today's Topics:

   1. Re: Ampex High Speed Dubber and later VHS systems (Dennis Degan)
   2. Re: High Speed dubbing (Scott Thomas)
   3. Re: Ampex High Speed Dubber and later VHS systems (Dennis Degan)
   4. Re: High Speed dubbing (Don Norwood)

----------------------------------------------------------------------

Message: 1
Date: Thu, 11 Mar 2010 15:29:11 -0500
From: Dennis Degan <DennyD1 at verizon.net>
To: Quad List <quadlist at quadvideotapegroup.com>
Subject: Re: [QuadList] Ampex High Speed Dubber and later VHS systems
Message-ID: <525BD493-E11C-4F4A-A7CC-7BABE87A862D at verizon.net>
Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes

		On Mar 11, 2010, at 2:42 AM, Mark Anzicek wrote:

 > 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.

		I say:

	Editel in New York had a 5-copy station Ampex machine.  I saw it
(and  
the mirror-master AVR-1 to go with it) in Feb 1979.

			Dennis Degan, Video Editor-Consultant-Knowledge
Bank
	  					NBC Today Show, New York

------------------------------

Message: 2
Date: Thu, 11 Mar 2010 15:32:23 -0500
From: Scott Thomas <scottgfx at mac.com>
To: Quad List <quadlist at quadvideotapegroup.com>
Subject: Re: [QuadList] High Speed dubbing
Message-ID: <4871F186-F1C4-4786-A18F-7936AD32743C at mac.com>
Content-Type: text/plain; charset="us-ascii"

I've often wondered what an open-reel VHS machine would look like. Page
4 of the brochure has my answer. :)

On Mar 10, 2010, at 5:57 PM, Don Norwood wrote:

> Bob:
>  
> Thanks for the detail on the Otari system.  I've uploaded a copy of
> the Sony brochure for their system which used magnetic transfer as was
used with the quad duplicator.  I believe their bin system also cured
the problem with the loop folds and regular tape was used for the dubs.
The brochure also shows the Sony mirror master recorder.
>  
> http://www.digitrakcom.com/TechDocs/SONYsprinter.pdf
>  
> Don Norwood
> Digitrak Communications, Inc.
> www.digitrakcom.com

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Message: 3
Date: Thu, 11 Mar 2010 15:33:23 -0500
From: Dennis Degan <DennyD1 at verizon.net>
To: Quad List <quadlist at quadvideotapegroup.com>
Subject: Re: [QuadList] Ampex High Speed Dubber and later VHS systems
Message-ID: <0DD2A008-105E-4DF0-B5A0-DD69BA1D1DA1 at verizon.net>
Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes

		On Mar 11, 2010, at 2:42 AM, Mark Anzicek wrote:

 > 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.

		I say:

	No Mark, that was excellent!
	You know engineers: There's no such thing as 'too much technical

information'!

			Dennis Degan, Video Editor-Consultant-Knowledge
Bank
	  					NBC Today Show, New York

------------------------------

Message: 4
Date: Thu, 11 Mar 2010 15:56:50 -0500
From: "Don Norwood" <dwnorwood at embarqmail.com>
To: "Quad List" <quadlist at quadvideotapegroup.com>
Subject: Re: [QuadList] High Speed dubbing
Message-ID: <3223D971A3A94632AB60B1E7F0BF64F9 at dcidell2v2>
Content-Type: text/plain; charset="iso-8859-1"

  ----- Original Message ----- 
  From: Scott Thomas 

  I've often wondered what an open-reel VHS machine would look like.
Page 4 of the brochure has my answer. :)
Scott:

And this is the Otari version:
http://www.digitrakcom.com/Pics/OtariMirror1v.jpg

The complete scanner assemblies were rebuilt as needed and even shipped
in cases very much like quad heads when they were rebuilt. Here's a reel
case showing the Sony part number for the mirror master tape:

Don Norwood
Digitrak Communications, Inc.
www.digitrakcom.com
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