5) I used adhesive-backed copper shielding for the contacts in both clamps.
6) The ribbon forming.
I suggest you try Larry Killip's suggestion on his webpage. http://www.lkmusic.co.nz/ribbonfix.htm It must be corrugated to allow for tension without being tight (if that makes sense to you). Try
his technique first, and be prepared to fail quite a few times before you get it right. After you learn how YOU do it
best, it is easy after that. There really is no wrong answers, just what is right for you to make it work!
I have developed my own techniques that I will share with you if you ask.
But here are some tips
1) wash EVERYTHING with isopropyl alcohol before you start the ribbon
cutting and forming. Your hands, you table surface, ruler, everything. You don't want any grease on anything,
or the ribbon will stick to it and won't come off without leaving a good portion of the ribbon behind. If you think
it's clean, clean it again.
2) Static and the ribbon do not mix. try to take the static
charge off of everything as much as possible.
3) I find it better to work with the ribbon when it is DRY.
Larry suggests using mineral oil or alcohol while working with it, but it seems to be much easier for me dry, and also, the
ribbon holds its corrugation much more without the weight of the fluid.
4) Use a piece of plexiglas as your straight edge for cutting the
ribbon. This allows you to pre-measure the ribbon width on the plexiglas and lay it down on the sheet of silverleaf.
This lets you see the ribbon and its reaction to the cutting, pressure, and also lets you keep tabs on the size of the ribbon
slice. If both the plexiglass and the surface are very clean and static-free, you can easily readjust the ribbon material
to the right dimension (which you can't do if your straight edge is opaque).
5) If you can't hold your breath while you are working with the ribbon,
go to a hardware store and buy some cheap tube to run out of your mouth and over your shoulder. It worked for me until
I got used to being aware of where every breath came from and was going while I was working with the silver leaf.
6) Let the ribbon go where it wants to go. The ribbon is so
thin and light that it will want to fly with the slightest breeze. don't fight it or it will rip. If everything
is clean and static free, it won't stick to anything, so it won't hurt to let it go a little wild and where it wants to.
7) I inserted the ribbon into the gap of the magnets and positioned it in the clamps. This is a little
more difficult than it sounds, because the width of the ribbon and the width of the magnet gap are pretty close. Getting the
ribbon to be as close to both sides of the gap without touching is a pretty tough job if you are as precise as I was, but
being super-precise is not absolutely necessary. In my experience, though, it can make a difference, especially
in output. Also, the ribbon can't be twisting or sagging, and you have to be careful not to pull out the corrugations.
The ribbon also must be pulled to a fair tension, but not tight enough to pull out the folds. The tension has
to be tight enough for the ribbon to hold itself up without sagging.
Another tip. Take a Volt/Ohm meter to check to see if the ribbon is touching the
magnets. It has worked for me a couple of times, and has shown that even though it may have looked great, I actually
had a connection between the ribbon and the magnets. It works on any magnet that's not coated with a non-conductive
surface. Just take one probe and put it on an end of the ribbon mount (in contact with the end you intend to solder
to the connection wire) and put the other probe on one magnet, then the other. In a resistance setting, it should reveal
even the slightest connection. The resistance will be very high, so if your meter does not auto-select for resistance,
I'd set it to high setting.
8) All the other materials were just junk and pieces I found that would work for mounting the base and
for the casing. You should also keep in mind that the whole mic will need to be shielded really well. I made the
casing excessively large to let me get my hand inside of it and apply shielding. Also, it is wide enough for the transformer,
and plenty wide enough to accomodate any future preamps, circuits, etc.
9) I assembled everything, wired up the element (being mindful to twist the leads to reject as much Electro-magnetic
interference), wired everything into the transformer, and...bingo. Ribbon microphone.