Thank you so much for the answers, will do some research now :)
Highly unlikely with the head from a VCR (you do know that a VCR head spins, right?) - and unlikely with the cassette tape head (but you'd have a better shot).
Don't know about vhs but on a tape player the head doesn't spin, the tape itself spins against it. Just like the magnetstrip back on a card is swiped against a maghead.
Basically, IIRC, there are more tracks on a magstripe, and they are spaced closer together than the 4 tracks on a cassette head; at best, you would probably get crosstalk from multiple tracks - but it might be worth experimenting with.
There's 3 tracks on a card but track3 are almost never used.
I would first do some more research on this topic, though; I'm sure if you care to brave the mess of various hacker forums you'll find a ton of information on card magstripe reading (and writing). Its not as easy as you think...
Finally (depending on where you are located), it might be better to look into obtaining a complete mag swipe unit (that has the head and slot at minimum; if you can get the amplifier circuitry, even better); I've seen such units on the surplus electronics markets every now and then (All Electronics used to carry them; not sure if they still do - also Electronic Goldmine). I've also found Verisign units being sold on occasion at local Goodwill stores; hit 'em up on 50 percent off day, and you can get a real bargain (hey, you'll also get a dot-matrix multi-character VFD in the mix to boot).
I am well familiar with hacking forum since I have study computer security the last 8 years and I have several msr readers at home, both usb and portable and a msr writer. But yes you're right, I should do more research about the difference but it's very hard because I can't find a term to search for. But will begin researching about how vhs and tapes are read and then compare it to the information I know about magnetic stripes.
Basically read write heads are just a coil on a fancy former. As such there is no polarity. In fact most have an AC voltage applied to them in order to record magnetic information.
Could you please explain what you mean with the AC? From those magheads I have there's simple two pins (vcc and gnd) but then there's magheads for clock/data etc but never mind about those at the moment.
Do you mean that it doesn't matter if I have gnd connected? I have done some experimental with arduino uno and a simple maghead. It looks like a got a smother input when gnd is conected (whooaa) and a more stuttering (tic-tic-tic extremely fast) input when it's not connected.
Again thanks for the answers,
Edit: Now I have done some simple research, took me a while finding it on wikipedia.
Here is magheads http://en.wikipedia.org/wiki/Disk_read-and-write_head
I have compared it to other articles on wikipedia and found out that there is no difference between readers/writers on card readers or in tape/vhs players. There all the same.
But final question is, connect or not connect gnd and what's the difference?