Originally Posted by WildcatMatt92
I've physically handled U-Matic stock -- the station I worked at in the late '90s used it to broadcast commercials and what the station would do is buy bulk 20 minute tapes new. A commercial would be placed on the tape and marked with cue tones. We'd air it until the client said stop or we noticed the playback beginning to degrade.
Then we'd "strip aircarts" -- play the tape to the end of the spot, eject it, cut the tape with a scissors, then yank the tape onto the floor all the way back to the clear leader, cut it, then scotch tape it back together and reuse it.
So from my memory, the U-Matic stock was noticeably thicker. Maybe still not as robust as the EIAJ stuff but certainly moreso than VHS. I actually have enough NOS 3/4" that I'm willing to sacrifice one except I don't have a way to accurately slit the stock down to size.
Given that Betamax was conceived as a cost-reduced U-Matic, I'm wondering how that influenced the tape stock, and whether there may be a difference in tape thickness between, say, newer L-500 blanks and if I got a late '70s rental tape off of eBay
The objective I'm really aiming for is something I can make a sample recording on one of the machines and then play it back on 1-2 of the others to see how they handle it. It wouldn't be for recording anything I would expect to keep and if it was only good for 3-4 playbacks before the tape would stretch that would be okay.
One thing I want to do is understand how close the skip-field CV series signal is to the EIAJ standard and whether playing a CV tape back on an AV machine (and vice versa) gives any indication that there's a recording there that it can't parse (eg, audio only, scrambled picture, etc.).
This is in equal parts toward understanding the potential for identifying recovering otherwise lost TV shows recorded on one of these old tapes and also as a method for generating for interesting video effects. (Flipping the Color/BW switch on the color EIAJ machines never fully kills the color, for example.)
I'm also interested in learning to use an oscilloscope to work on some of these machines so their simpler electronics seems like a good place to start.
It's definitely a cool project.
I could get really nerdy on this but the 1/2" cassette stock (Betamax, VHS, Video2000) is quite different to UMatic stock, part of that was making a thinner substrate tape to accommodate the smaller cassette form, if you tried to wind 750 feet of UMatic tape it would be a chunky tape pack and would have been outside of Sony's spec for the Betamax cassette, obviously ignoring the tape width.
Sony determined the size of the cassette as 0th specification for the Betamax system, based on the Sony staff handbook which was an approximately A5 pocketbook.
There are (and this is conjecture) considerations regarding shuttling of tapes, UMatic would have (at least in principal) been subject to repeated shuttling during editing operations which I'm not sure the chemistry at the time would have allowed at a reasonable cost on thinner tape. That's just my conjecture though.
I do have hundreds of Betamax and Betacam tapes in the office with me, the tapestock on the later tapes is arguably thicker as (possibly.. this is debatable, it's not clear) it's Betacam tape. Cassette casings for late (mid 90s onward) Betamax tapes are often the same moulding as Betacam SP cassettes and the later 'Metal' tapes almost certainly contain Betacam SP stock. These are the very end of the line Betamax ED tapes for the last gasp attempt at outdoing S-VHS, about a decade after would have stood any chance of getting any foothold in the market.
Basically, I'm convinced that the very late Betamax tapes were simply differently packaged basic Betacam SP tapes. That's only based on the ones that have passed through my hands, and I've not done any chemical analysis on them!
I do have some new oxide (Maxell brand) Betacam tapes, I can compare these with Betamax tape as they may be a touch more durable, I'll check tomorrow. These might be a good, slightly thicker ferric tape and easily available.
Don't use 'metal' tape with this machine (Betacam SP), I'm almost certain you'll get very poor results. Recording strategies for metal tape are rather different to ferric blends or ferrochrome.
I can't speak to the standards, CCIR-A was more common here in this era and beyond very basic explanation I'm not very good at that so EIAJ is well beyond me in scope.
It's always cool to hear about how things were in studios, it's something that fascinates me, I came into this sort of thing long after routine tape work was being done. I worked in radio for a bit, which was never as exciting, carts just got scrubbed and reused, nothing exciting... Where I worked ad sales were so poor ads were often being played out gratis well past their campaign end anyway just to fill some gaps.
It's a cool as frig device, yet simple enough to comprehend so it's going to be a great learning tool.
After years of being a Tektronix fanboy, I've switched to a modern and modest Rigol unit for my own fiddling endeavours and it's a fantastic little unit. It's amazing how far 'scopes have come now. Don't be scared of a modest 'scope like a Rigol or similar now, they're wonderful little units if you're in the market for one. There's not been a better time to learn this stuff with good quality budget units available coupled with tons of online information.
Always get a decent multimeter first though
If you've not got a halfway decent multimeter start there is my tip.