[QuadList] Quad comparison

Guy Spiller quadruplex at verizon.net
Wed Jun 10 20:49:05 CDT 2009


Hi Park...
I'd have to guess that the "stock" 1200 was on the right, and the only 
real clue for me was the giant dropout near the beginning that just 
shows on the right half, and I didn't see that you mentioned the stock 
1200 having a DOC.
The difference in luminance level in some scenes looks to be more of a 
difference in a clamp somewhere in the video processing, as not only do 
the upper levels of luminance appear different in some scenes, but the 
near blacks seem to change as well in those same scenes.
It would be interesting to see a horizontal split with modulated stairstep.
Guy

C. Park Seward wrote:
> http://www.youtube.com/watch?v=I95CbfX0puk
>
> I have put on youTube, for educational purposes only, a comparison 
> between a stock Ampex VR-1200B and an Ampex/Merlin Edition 1200B with 
> the NEC digital TBC.
>
> Can you spot which one is on which side?
>
> Yes, the compression makes it difficult to see any difference. Be sure 
> to hit the "HQ" button.
>
> The audio is matched to the side of the machine. The left screen is on 
> the left channel.
>
> The machines are within one frame. Since DV only compresses in frames, 
> I could not trim by a field.
>
> Interesting that some scenes are a perfect match in luminance but 
> others are not with the same video settings. That suggests the 
> linearity of the systems differ.
>
> Both VTRs look good, but I can see a difference on the master miniDV 
> tape. The video was recorded on miniDV and edited in DV with Final Cut 
> Pro. That was output to H.264 for the upload to YouTube.
>
> The tape was recorded in Japan in the middle 70s. Both machines were 
> cleaned prior to playback and both have the 4.5 MHz low pass filter. 
> The Ampex 1200B has  Amtec, Colortec, Vel Comp and Proc Amp,  while 
> the Merlin edition has Vel Comp and DOC inside the TBC and no Amtec or 
> Colortec.
>
> Best,
> Park
>
> C. Park Seward
> Visit us: http://www.videopark.com
>
>
>
>
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-- 
Guy Spiller
email: quadruplex at verizon.net
phone: (804) 379-2050
website: www.GuySpiller.com
Midlothian, VA





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