[QuadList] Blanking Issues

[Preservation]

Good point about politics and design by committee. Like Sony jumping  
the gun on the color EIAJ standard with their pilot tone system which  
they assumed would be adopted, and the committee responding by going  
with the JVC color under system. That left a lot of AV-5000/5000a  
machines hanging in the wind.

Regarding the early Sony U-matics, weren't they built on or derived  
from the AV-8650 chassis?

Bill Seery

preservation at standby.org
212.627.8070




On Feb 7, 2010, at 6:30 AM, Trevor Brown wrote:

> I think you need to separate politics from engineering
>
>
>
> C format came from a committee on which Ampex and Sony both had seats
>
> Ampex were already up and running with a very nice helical and so  
> had a market lead
>
>
>
> Sony insisted sync heads to record the missing part of the picture
>
>
>
> Once these heads became spec even if you did not want to record  
> blank lines, you had to fit dummy heads to maintain interchange
>
>
>
> Sony always insisted it was for non TBC machines so you could fill  
> the missing band with tape info
>
>
>
> The fact that it was recorded at the other side of the drum where  
> the tension is different and so could not be used with processing  
> seemed to be overlooked
>
>
>
> And Ampex had to redesign the scanner and loose there market lead
>
>
>
> Apologies to any Sony people, but dummy heads or sync head was  
> politics not engineering
>
>
>
> Trevor
>
> UK member
>
>
>
> From: quadlist-bounces at quadvideotapegroup.com [mailto:quadlist- 
> bounces at quadvideotapegroup.com] On Behalf Of Scott Thomas
> Sent: 07 February 2010 06:59
> To: Quad List
> Subject: [QuadList] Blanking Issues
>
>
>
> Talking about Type-C for a moment; I can't remember if it was Sony  
> or Ampex (or both?), but they had a separate "sync" head on the  
> scanner. I'm assuming that was to have a clean sync pulse on the  
> head switch? A problem obviated by a TBC?
>
>
>
> Scott Thomas
>
>
>
> On Feb 6, 2010, at 5:20 PM, Don Norwood wrote:
>
>
>
> Hi Park:
>
>
>
> All of the Type-A 1" machines up thru the VR-7800 had the switch  
> above the vertical interval.  The VPR-7900 was the first to place  
> it in the vertical.  Remember also that the Type-A machines are  
> single head, so there is more than a "switch", there is a dropout  
> for several lines.  The VR-660 is a 2-head design so there is a  
> switch and no dropout.
>
>
>
> When Sony made their first 1/2" machines, there was apparently some  
> "reverse engineering" done on their Ampex predecessors.  Although  
> the Sony machines were 2-head, they had a "blanking" circuit that  
> covered up the switching point and produced a totally blank area in  
> the same location as the Ampex Type-A.  There was no logical reason  
> for that other than replicating the output signal of the Ampex.   
> The practice was discontinued in subsequent models.
>
>
>
> Don Norwood
> www.digitrakcom.com
>
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