[QuadList] What is it????

Fri May 13 22:15:43 CDT 2011

I saw the front extrusion and knew that it was the same as the VR-7800 and  
VR-7900 plus the AVR-2.  This style was also used by the audio  people.  

I was under the impression that it was a quad so that is why I went to the  
AVR.  I wonder how they were able to keep the cost down using the AVR-1 TBC 
 design rather than another type.  This would be a question for Bill  
Carpenter.  

I always was under the impression that the AVR-1 buffer was way too costly  
to manufacture.  That is why the ACR-25 went to the B model that had a  
digital TBC.  

I await for the comments.

Chris Hill

In a message dated 5/13/2011 11:08:26 P.M. Eastern Daylight Time,  
dwnorwood at embarqmail.com writes:

And once again, Chris is the winner!!!!

Bill Carpenter told us about a mini buffer (TBC) that  was designed for the 
VR-1400, a VR-1200 fitted with the new TBC to  replace 
Amtec/Colortec/Velcomp/ProcAmp, but the machine never became  a product due to the development 
of the AVR-2. However, the TBC design  went on to become the TBC-790, 
intended for use with the  VPR-7900.

Ampex used some of the modules from the AVR-1 as well as  some newly 
designed modules, but the card cage design of the TBC-790 was  different in 
several respects from the AVR-1.  For one thing, there were  coax connectors in 
the AVR-1 back plane, but not in the TBC-790, so the  coaxial connections that 
would normally have mated with connectors on the rear  of the modules were 
instead routed to connectors on the front panel.  I  suspect that was done 
to save cost, however, another difference has always  puzzled me.  For 
whatever reason, the card frame in the TBC-790 is  "upside down and backwards" as 
compared to the AVR-1, so the re-purposed cards  (which were not re-labeled) 
have connector pin numbers that are opposite of  what you would expect.  

Otherwise, the mechanical design of the modules is unchanged  except for 
the extruded aluminum handle that runs the length of the module  instead of 
the "loop" handle on the AVR-1.  It's the same design as used  on the AVR-2, 
VPR-7900 and VPR-7800.  Here's a pic of the module  installed in a TBC-790 
with jumpers between modules taking the place of the  back-plane connectors in 
the AVR-1.

Interestingly, in the TBC-790 manual, for the modules that  were "borrowed" 
from the AVR-1, there was no re-working of the drawings to  match the new 
configurations for the TBC.  The pages from the AVR-1  manual were simply 
copied, ignoring the changes in the mechanical design and  the pin numbering!

Don Norwood
Digitrak Communications, Inc.
_www.digitrakcom.com_ (http://www.digitrakcom.com/) 

----- Original Message ----- 
From:  _Chill315 at aol.com_ (mailto:Chill315 at aol.com)  
To: _quadlist at quadvideotapegroup.com_ 
(mailto:quadlist at quadvideotapegroup.com)   
Sent: Friday, May 13, 2011 10:37  PM
Subject: Re: [QuadList] What is  it????

Then there is only one answer.  It is for the TBC that was  designed for 
the VR-7900 type A machine.  

Chris Hill

In a message dated 5/13/2011 10:25:51 P.M. Eastern Daylight Time, 
_dwnorwood at embarqmail.com_ (mailto:dwnorwood at embarqmail.com)   writes:

Hi Chris:

No, I didn't say it was for a quad, just that it was  "firmly rooted in 
quad history".  You got part of that answer  right!  And Park got the 1" TBC 
part right.  And Bill Carpenter  told the whole story not too long ago 
including how this fits with the  "quad that never was".  I figured one of you guys 
would put the  pieces together!

Don Norwood
Digitrak Communications, Inc.
_www.digitrakcom.com_ (http://www.digitrakcom.com/)    

----- Original Message ----- 
From:  _Chill315 at aol.com_ (mailto:Chill315 at aol.com)  
To: _quadlist at quadvideotapegroup.com_ 
(mailto:quadlist at quadvideotapegroup.com)   
Sent: Friday, May 13, 2011 10:13  PM
Subject: Re: [QuadList] What is  it????

Yes I did notice that the module was missing the pull handle.   The card 
does have the 28 pin connector that the AVR-1 used.  The  63.5 micro second 
delay line is used in the drop out compensator of the  AVR-1.

The front connectors are what throw me for a loop.  So I am at  a loss.  

It is for a quad you say so that does not leave much left.

Chris Hill

In a message dated 5/13/2011 10:09:05 P.M. Eastern Daylight Time,  
dwnorwood at embarqmail.com writes:

Hi Chris:

Almost a winning answer, maybe the best so  far.....but you'll notice that 
this module design (mechanical, not  electrical) is slightly different from 
the AVR-1.

Don Norwood
Digitrak Communications, Inc.
_www.digitrakcom.com_ (http://www.digitrakcom.com/)    

----- Original Message ----- 
From:  _Chill315 at aol.com_ (mailto:Chill315 at aol.com)  
To: _quadlist at quadvideotapegroup.com_ 
(mailto:quadlist at quadvideotapegroup.com)   
Sent: Friday, May 13, 2011 9:54  PM
Subject: Re: [QuadList] What is  it????

This is the one line delay module that was used in the AVR-1 /  ACR-25.  

Chris Hill
WA8IGN

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