[QuadList] Quad comparison

[C. Park Seward]

Yes, the right side is the stock Ampex.

When doing some testing I did notice a rough luma ramp and adjusted  
the quantizing level and got it flat. So the aliasing we saw is now  
gone.

Best,
Park

C. Park Seward
Visit us: http://www.videopark.com



On Jun 13, 2009, at 8:24 AM, Chill315 at aol.com wrote:

> I believe that the machine on the right is the VR-1200 with the  
> original Amtec and Colortec.  Here are my reasons.
>
> 1    The drop out that occurs is filled in by black.  This is what  
> the Non- 3M DOC would do.
>
> 2     The aliasing of the video is more pronounced on the left  
> side.  The use of the 8 bit NEC TBC and the digitizing two more  
> times would show up more pronounced.  Especially if the linearity of  
> the A-D and D-A s are not perfect.
>
> The rest of the picture looks very good.   I do notice the  
> difference in black levels.  The AMPEX Proc amp and the NEC TBC  
> probably treat zero set up differently.  Since I have no experience  
> with this, I can not use this as a determination.
>
> Chris Hill
>
> -----Original Message-----
> From: C. Park Seward <park at videopark.com>
> To: Quad List <quadlist at quadvideotapegroup.com>; Old Vtr <oldvtrs at yahoogroups.com 
> >
> Sent: Wed, Jun 10, 2009 7:00 pm
> Subject: [QuadList] Quad comparison
>
> 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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