[QuadList] Fwd: Quad VTR Quadrature Compensator

[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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