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Could a player be made to play both CEDs and VHDs?
https://forum.lddb.com/viewtopic.php?f=16&t=340		 Page 1 of 1
Author:  cessnaace [ 06 Nov 2011, 07:00 ]
Post subject:  Could a player be made to play both CEDs and VHDs?
Both formats are capacitance based systems. CEDs have grooves, VHDs do not. I know the pickup designs are quite different, but could a CED player be modified to play VHD discs, using a pickup design that woulld read both types of discs? VHDs last longer, and from what I've seen look better than CEDs, but there are alot more releases for CED (at least in NTSC).

I'm sure that there are many VHD exclusive titles, and vice versa. I'm thinking that it would have to be a CED player modified to play VHDs, as opposed to the other way round, because CED caddies are larger than VHD caddies. If someone would make such a thing as a home project, add me to the list of buyers. :clap:


STAY AWESOME! :)
Author:  publius [ 06 Nov 2011, 07:57 ]
Post subject:  Re: Could a player be made to play both CEDs and VHDs?
To construct a mechanism to handle both sizes of caddies would be difficult at least. Recall also that VHD is smaller in diameter than CED, & CED at least (not sure about VHD) is read from the outer edge inward, rather than from the center as is true of LD. And that is before we get to the actual playback.

VHD uses pits in a flat surface, much like LD, & tracking depends on a second set of pits over which the pits representing the video signal are superimposed. CED tracks by guiding the stylus in a V-shaped groove, the bottom of which is ridged to correspond to the half-cycles of the FM signal. The CED grooves are much broader — it is a 450 RPM system where VHD is 900 RPM, so VHD fits twice the number of grooves into 5/6 of the space.

There's a good reason why you don't play SP records (78s, that is) with an LP needle, or vice versa. The same general reasoning applies to CED & VHD. They are broadly similar, but that's it. You wouldn't wash your dishes in the laundry machine, either.
Author:  beetlescott [ 07 Nov 2011, 07:21 ]
Post subject:  Re: Could a player be made to play both CEDs and VHDs?
I can't see how it would be possible. Interesting, but not doable.
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