[QuadList] Fwd: Quad VTR Quadrature Compensator

[Ted Langdell]

BBC had a head program, as outlined on the VTOldBoys website:

http://www.vtoldboys.com/memomenu.htm

Worth reading.

Definitely NOT "Shove in tape, punch Play."

On Mar 31, 2010, at 8:06 AM, David C. Crosthwait wrote:

> 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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Ted Langdell
Secretary