[QuadList] quad videotape stock question

[Don Norwood]

Hi David:

Interesting.  An old catalog I looked at on Ampex 456 indicated it's 1.5 
mil, but a later Quantegy sheet agrees with your numbers.  An additional 
0.43 mil certainly is a significant difference!

The other confusing thing is that reel size/tape-time is the same for 10.5" 
(1/2 hour) reels of quad tape or audio at 15 ips.  But once you go beyond 
the 10.5" reel, things change.  Hour reels of quad tape are 4950' on 12.5" 
reels while 5000' of audio tape is on 14" reels.

Next time I change a quad head, I'll use an old head and experiment with the 
range of the guide position on some audio stock.  I think there's plenty of 
adjustment to accommodate it, but I'm curious now that you've brought it up. 
Since there was some 1.0 mil quad tape (which allowed 30 minutes on an 8" 
reel for the VR-3000), it seems like a 0.5 mil difference shouldn't be a 
problem but it may depend on where the "center" is set.

Don

----- Original Message ----- 
From: "David Dean" <dixie at westpoint.tv>
>
> Hi Don
>
> I have just measured some Quad Tape and I get a reading of 0.04mm which
> agrees with you, what I didn't understand is why the running time of Audio
> tape is shorter if the reel sizes and the speed are the same. I asked an
> audio friend to measure some 456 and he measured it as 0.05mm, he also 
> says
> that there can be difference in thickness, thicker tapes have higher
> saturation points (eg Ampex 499) with more oxide at 0.06mm. I have just 
> had
> a look at the Quantegy brochure and it states a thickness of 1.930mil,
> .0489mm, so that explains the difference. See link
> http://ebookbrowse.com/quantegy-456-pdf-d34081107 (page2)
>
>