DIY tape rec/repro heads

[Steerpike]

Originally Posted by gain-wire

Now I realize that the problem in making my own core laminations (I don't even know why they are called laminations, it's just one piece of metal per head track right?) is that to slice the metal out of a thin sheet, you get burrs, and you can't cleanly file them out, so you wreck the edges where it's supposed to be perfectly square. And they didn'T have laser cutting in the seventies, so how did they make them?

As far as I know the laminations were/are punched out of sheet metal.
Laminations (from the latin 'lamina', a thin sheet). The laminations need to be electrically insulated - by coating with a layer of varnish sometimes - to minimise the circulation of eddy currents induced by the magnetic fields. Eddy current would waste energy and degrade the field.

Ferrite is an electrical insulator, so does not need to be laminated, and can be cast in a single solid form. I think VCR heads are made of similar such stuff (harder than basic ferrite), for their high frequency magnetic characteristics.

I'm not up on imperial head gap numbers! Typically, playback gaps are around 1 micron (um) and record around 4um.

As mentioned my Kevinkr, transformer steel (the easiest to get) may prove mechanically too soft to be durable. Are Ampex heads made in 1950 likely to be more exotic material-wise than was available to Studer for their Revox heads?

I have a few of the cylindrical Revox heads (worn out), and while the potting may be cosmetically 'ugly' I don't think that has any detrimental effect of the performance.

[gain-wire]

Thanks Kevinkr and Steerpike, you've provided good input. I guess I wasn't aware of all those considerations. You obviously know things I don't!

Luckily for me I already have some 9 track tape heads from old Kennedy computer mainframe tape drives, and I will be using them. If I have time and ressources I will commit to building a head.

Until then I think I shall reconsider!

[Geek]

Originally Posted by gain-wire

amazing... #56 is 0.00049inch. It's not even one thou. That's much smaller than a thin hair! I had no idea they could make it that small.

Kinda useless for us... it'll disappear as soon as the soldering iron touches it

Special tools needed for sure!

Cheers!