[QuadList] Fwd: Quad VTR Quadrature Compensator

[David C. Crosthwait]

George and Chris,

NBC had one guy in maintenance who basically did nothing but heads. He  
knew it all. He had been there, done that. VR 1000's and TRT X  
machines onward. I learned a lot from him before he passed away a few  
years back. I recently talked with his widow about all the projects he  
had been involved in over the years.

David



Quoting georgenann at aol.com:

>
> Hi Chris,
>
> All I remember is that it was just a case of reducing the errors.    
> If you moved one head you have now screwed up the whole pattern.    
> You had to then move all the other heads to compensate.  This meant   
> starting, stopping the head, etc.  It could take all day.    
> Fortunately there were two guys who did nothing but heads, a   
> carryover from the old days. If I remember, you had to start with   
> head #4 and work your way around.  I don't remember ever having just  
>  one head out of quad and just moving it back into place.
>
> I agree most of the heads were done very well, I don't know how they  
>  got them right so many times on so many heads, must have been some   
> kind of laser alignment set up.  Did they have lasers back then??
>
> Don't even ask about setting up the jumpers on the proc board. Thank  
>  God most of them were set up correctly before I went in to Tape  
> Maint.
>
> Hope this helped.
>
> 73,
>
> George Keller
>
>
>
>
>
>
> -----Original Message-----
> From: Chill315 at aol.com
> To: quadlist at quadvideotapegroup.com
> Sent: Tue, Mar 30, 2010 11:16 pm
> Subject: Re: [QuadList] Fwd: Quad VTR Quadrature Compensator
>
>
> George
>
> I never had the thrill of working with the early heads on a VR-1000   
> series.  How did you go about setting quadrature on these early heads?
>
> All the heads that I got in the 60's and later were so good that we   
> never had to do anything to them.  At that time the manufactures got  
>  the quality to a point where this was not a problem.  Also the  
> AMTEC  and ATC took care of any error.  The only time I would see it  
> was  when the AMTEC error had a step for one head only.
>
> I think the most that I ever had to adjust on the TRT was only a few  
>  clicks from center on the delay lines.  I can only picture it in my  
>  mind and by looking at a picture of the electronics in the   
> instruction book, I only think it was a few clicks.  The book calls   
> it out as .015 micro seconds per click.  Interesting was the design.  
>   the record amp had a 6922 with a single gain control then feed a   
> set of 6922s for each channel.  They fed the delay lines.  Then a   
> 6922 was the output driver for each channel.  The output of this   
> chassis fed the record driver chassis.
>
> The playback amps were 6BQ7 tubes with individual gain controls that  
>  fed the delay lines.  Again the same amount of delay per click.    
> Then another 6BQ7 to fee the next chassis.  The playback delay was   
> right after the pre-amp and before the equalizer.
>
> Chris Hill
> WA8IGN
>
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David Crosthwait
DC Video
Archived Media Transfer and Re-mastering Services
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