[QuadList] The Digitrak Tape area

[Don Norwood]

Hi Chris:

On th 7800, the proc amp was on the right end of the main front card cage.  The two rear card areas accessible from the top of the machine were for heterodyne color and dropout comp.  The 7800 was before any TBC was available.

The VPR-7900 was the first machine to have a companion TBC.  While the machine looks much like the earlier 7800, there are some major differences.  Probably most significant would be the addition of a 3rd carrier mode which is the same as Hi-Band quad and 1" Type-C, and the servo system which was the first 1" to have H-lock capability, allowing it to work with the small correction window that was then available with analog TBC's.  There are many other differences, but along with direct color recovery (no heterodyne), the VPR-7900/TBC-790 made 1" truly broadcast capable for the first time.

The biggest problem with the 7900 (and all of its Type-A predecessors) was the movable guides.  That of course was fixed with the VPR-1.  However, as visitors here can attest, the 7900 when properly set up looks just as good as Type-C.  To be fair, we use a TBC-7 instead of the original TBC-790, so correction range is much greater than the original, but the 7900 was the beginning of proving that 1" could be a viable alternative to quad.

Don Norwood
Digitrak Communications, Inc.
www.digitrakcom.com
  ----- Original Message ----- 
  From: chill315 at aol.com 
  To: Quad List 
  Sent: Friday, April 19, 2013 12:41 AM
  Subject: Re: [QuadList] The Digitrak Tape area






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  I had a 7800 and it was not that great a machine.  The proc amp may have been under the right rear cover.  Then the left rear may have been for a simple TBC.  can anyone confirm that?

  Chris Hill

  On Apr 19, 2013, at 12:11 AM, "Don Norwood" <dwnorwood at embarqmail.com> wrote:




    I knew David would know!  Here's a pic of the other VPR-7900 we have before a capstan replacement.  There's even sort of a quad connection here. The original TBC-790 which was paired with the 7900 is an analog design and Ampex used some of the same modules as in the AVR-1.  However, we now use TBC-7's which work much better!

    <vpr7900sml.jpg>

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

    ----- Original Message ----- 
      From: David Crosthwait 


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      Yes Don it's your 7900.



      Best Regards,

      David Crosthwait


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