another thing to bear in mind with this idea is that VHS tapes have a helical scan. this means that the tape needs to move across the magnetic heads on a diagonal. this makes it somewhat more difficult to guide the tape to pass in/out of the unit and still hit the head correctly
The only time I’ve heard of a similar setup was talking to an older video artist who had magnetic video tape reel-to-reel machines. Those got around the helical scan issue Paloma mentioned and the tape could easily run outside of the machines.
Yeah open reel would be easiest, like with a couple Sony AV-86xx or AV-36xx, assuming you could acquire and restore them. I’ve wanted to do this for a long time.
With vhs, your best bet would probably be with a couple broadcast decks like the Panasonic AG-DS850 so you could have a sync reference and more control over the electronics calibration. But then you would need to heavily modify the deck to get the tape to move between players smoothly. There is a tension sensor that will stop playback if tension is too high or too low. And reel torque/speed sensors. I would try modifying a couple cassette shells so that you could still run the tape off the reels of each deck and trick the machine into thinking nothing weird is going on.
Another approach would be to pull the tape mech (including head assemblies) from each deck so you could set them next to each other, and then extend the wiring back to the electronics.
Not a light undertaking, but would be badass to realize.
Another consideration is that helical heads move really fast, so they don’t like tape splices. A splice or even a wrinkle in the tape can damage heads. Too abrasive.
Well I’ve made my first very basic loop, just one VCR and a pre-recorded tape.
I feel like pins with spools from inside a VHS tape would be enough to physically guide the tapes between the two decks. Then some way to adjust them precisely or perhaps springs tensioning them…
Beyond that I’m thinking about a spooling system like the Vocu tape delay has, but on both record and play sides to offer some mechanical separation between the two VCRs so they aren’t pulling on each other directly.
can you take out the head mech from a 2nd VCR and have it interact later with the same tape?
Again taking inspiration from the old school methods.
This may be difficult to implement!
If you take out the head assembly, you’ll still need the electronics that spin the head drum. Alignment (enough to get a usable signal) would probably be very difficult as well. Surely fewer headaches to find a second deck of the same model and have them face each other.
I really like the idea of stripping down the PCB more and exploring the possibilities of detached read heads.
There are clearly technical & physical issues that would need to be worked on.
Something interesting that I have noticed: it seems there is some kind of video buffer built into this VCR. The tape physically slows down at some points, especially where it has become wrinkled but the playback keeps going at the regular pace.
I’ll post the make and model with my next update.
Further learning: cut away more of the back of the VHS tape than you expect, almost right to the screws that hold it together. Longer loops come out at much shallower angles. Or Carefully position a spray can.
Also there’s a minimum extra length required because the tape is pulled out a long way to be played. I’m going to see if it’s at all possible to create a loop inside a tape case.
Keep in mind that the amount of tape pulled out by a VCR to line it up on the head is not a constant. Different models will pull different amounts of tape out, making an all-in-the-shell tape loop an engineering ride through hell.
yes twin decks, would be essential to have the same mech/elec.
I’ve started a project with a double tape deck doing similar ideas, but other problems with the decks forced closure.
Its a lot easier with audio tape, but possible with video too.
Stripped down twin VCR decks would be the simplest I think. You could mount the open frames on a board. Though still FAR from easy!
And having a 2nd read head, with a (dirty) mixer, like a tape delay would be interesting.
You’d not really need a physical loop with this either, the loop is in the read/read gap.
edit - what I mean is, one tape into the next deck/read mech rather than a short loop between them. There would have to be some physical looping between decks, but it could be longer.
