[sdiy] Scavenging the electronics graveyard

[René Schmitz]

Hi all,

>>> I have always wanted to make some sort of analog delay using a floppy 
>>> disk
>>> drive! Never gotten around to that though...
>>
>> Or something like a Mellotron!
>>
> 
> I tried this in the late eighties with an 8" floppy drive and it did not 
> produce good results. Then I tried it again with a 5 1/4" and still 
> things did not really work well at all. I was using all the guts from a 
> cheap tape recorder to do the work. I am sure that there was a problem 
> because the head could not be aligned properly, the media was crap, poor 
> head contact, and it seemed like just a tremendous amount of noise was 
> being picked up. Not to mention that on my prototype the switching from 
> record to play was done manually. Much easier on the 8" drive.
> 
> Not sure of the exact details ,but perhaps it could be a digital scheme 
> using the existing head and some software to do the read/write switching.

I think this is due to the magnetic properties of the coating. The stuff 
used for data storage is more magnetically hard compared to the stuff 
audio tapes are made of. (I guess many people have tried running 1/2 
inch data tapes in their audio desks...) You need a head that is capable 
of producing a much stronger field, to be able to properly magnetize it 
(see Coercivity).

Cheers,
  René