[QuadList] Intersync and Lock Up

[Guy Spiller]

I can definitely concur with Chris about RCA 3.58 stability.  What the 
servo has in stability, especially with temperature, the subcarrier and 
burst processing do not.
Even these 70Cs, need a good 20-30 minute warm up to get reasonably 
stable with system and chroma phase.  Fortunately, for how I use it, 
overall system phase isn't critical. 
I remember seldom having to fool around with burst/chroma phase on the 
1200/2000s, and that was a good thing, as I think it was a black 
variable inductor in the back right corner of the proc amp.  Xcelite 
green to the rescue yet again.  Is that right?  It's been a long time.
I guess that's the reason RCA put a big "chroma phase" knob on the play 
control panel!
Great discussion...and memories here.
Guy

Chill315 at aol.com wrote:
> The discussions and humor is very interesting. 
>  
> I had the last version of the Inter-Sync produced.  The machines were 
> manufactured in the early 70's.  It was very stable.  The only reason 
> that we let the head run for 30 minutes was to get the guide up to 
> temperature.  We found that the tip penetration would change as we 
> edited if this was not done. 
>  
> I also had a TR-60 that was serial number 5.  It would lock up in a 
> little longer time than the 1200's.  Every mod that was put out by RCA 
> was done to the machine but it still did not help.  The biggest 
> problem was getting a good solid lack of jitter from the machine.  
> Timing was always an issue.  It did not have a stable 3.58 phase 
> relationship with other sources.  Always a couple of degrees off each 
> time it played.  It worked great as a dub source but through the 
> switcher doing match frames was not the best.
>  
> Regarding the rolling of tape stock from ready or not ready.  The reel 
> boost comes on for about 1.5 seconds after the play button is pushed.  
> This is in all cases.  The guide comes in depending on if it is up to 
> speed.  Typically 1 second as determined by the sequence controller.  
> The pinch roller is the same.  If the head is not turning, than the 
> time for the two events is about 3.8 seconds. 
>  
> So which is better, letting the tape be under the control of the take 
> up and supply voltages setting the torque or letting the capstan 
> control the speed?  I think the answer is really depending on the reel 
> and tape pack sizes on the two turntable.  I can see where the reel 
> torques will either have the tape too slow or too fast before capstan 
> engagement.  Perhaps this is why the vacuum columns were invented on 
> the AVR-1. 
>  
> This would be an interesting discussion to have with the engineers 
> that designed the transport systems.
>  
> Chris Hill
>
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-- 
Guy Spiller
email: quadruplex at verizon.net
phone: (804) 379-2050
website: www.GuySpiller.com
Midlothian, VA