[sdiy] Tape head collage (pretty much not synth DIY, sorry)

[The Peasant]

OK, here is a cassette type electronic head demagnetizer:

http://www.electronicpeasant.com/misc/demag.jpg

Now does anyone believe me???

The tape head contacts a transducer assembly when it enters the cassette shell, 
which pushes on a small switch to begin the demagnetizing process. It is 
powered by the small mercury cell seen in the top left corner, and there is a 
small LED in the center that comes on when the process is complete. I works by 
injecting a slowly decaying high frequency AC signal directly to the head, 
which simulates what is done with a standard demagnetizing wand used correctly. 
Phono cartridges can be demagnetized as well (the coil assembly, not the 
internal magnets) using a similar type decaying signal.

Take care,
Doug
______________________
The Electronic Peasant

www.electronicpeasant.com


Quoting "Roy J. Tellason" <rtellason at blazenet.net>:

> On Thursday 25 November 2004 05:15 pm, Scott E. wrote:
> > I have never heard of a demagnetizing tape, only tapes that "clean"
> > heads. Demagnetizing involves the use of a hardware device that produces
> > a magnetic field for the purpose of demagnetizing the tape head. I also
> > think the best way to clean tape heads is with a cotton swab and
> > denatured alcohol.
> 
> The demagnetizers I've seen that were built into tapes used a little spinning
> 
> magnet,  driven by the mechanics that normally moved tape.  I was not 
> impressed.  I *think* there may be others out there,  with external power 
> connection that may be useful for a slot-fed player,  but I have no direct 
> experience with these.
> 
> > The technique of demagnetizing is not complicated, but one must be
> > careful, as done improperly, can actually magnetize the head even
> > further. The technique is to bring the demagnitizer close to the tape
> > head and move it back and forth for a few seconds, then, while the
> > demagnitizer is still on, remove it from the proximity of the tape head
> > slowly, moving the demagnitizer in a back and forth or circular motion.
> > Drawing it straight away would be a poor technique. It should be several
> > feet away from the tape head before powering it off. Also, the tape
> > machine should NOT BE POWERED ON while this procedure is performed.
> 
> Yes,  the recommendations that I've seen usually specify a distance of four 
> feet or more.
> 
> 
>