Alice mic kits 					2005

OK, here's what passes for documentation.  Definitely look at the photos, they show all the details.  This is not meant to be an easy kit – it's just meant to save you the hassle of rounding up some oddball little parts that I had to figure out.

A few notes:
Take your time, practice on scraps.  Cutting clean slots with a Dremel tool takes a bit of practice.  

Follow all applicable safety practices, of course.  Wear eye protection when using power tools, hearing protection as needed, etc.

Think a little bit about what order to do things in.  Several steps require waiting for glue or finish to dry.  You probably want to make the brass mesh windscreen after cutting out the windows on the mic body, but before cleaning and finishing the body.  Also, I don't bother to sand/grind the insides of the screwholes until after the finish is done, so that the sanding will clean off any overspray and allow a better ground connection.

Finishing:  I use a basic spray lacquer (clear) from the local hardware store.  I've tried several different techniques for cleaning and polishing the copper body, and for the most part you can do whatever you want.  I did figure out that actually polishing to a shine caused more problems, because a rougher finish tended to hide nicks and lettering in the copper pipe.  I originally used 220 grit sandpaper to start, then 400, and finally steel wool.  Now I use a fine brass-wire brush at high speed, which gives an interesting pebbly sort of surface.  Finally, I use 4-5 thin coats of the spray lacquer.

Extremely high impedance:  The 1Gohm resistor and FET on the capsule result in an extremely high impedance, very sensitive to noise and also humidity.  If you assemble the electronics outside of a metal body, expect a lot of hum.  To prevent humidity problems (especially if the mic is to be used for vocals) I clean that area with alcohol and then apply an electronics “conformal coating” using cotton-tip swabs.  You can actually use the same spray lacquer from finishing the body – just spray some onto a piece of tinfoil to get it in liquid form.  I did that on my first few mics and they are all still working fine.

Brass mesh:  This is the most annoying part of the build.  You can cut bits of paper to check the size before bending, but ultimately you'll end up doing a lot of very fine trimming until it's the exact size.  The nose-piece takes a lot of tweaking and trimming until it's the right shape and has a good enough edge for soldering to the side-piece.  I do the soldering with regular electronics solder and a Weller soldering station.  A 40-watt or hotter iron should be enough.

Adhesive:  In one of the pictures is a tube of clear silicone adhesive caulk.  There's nothing special about that particular brand, it's actually stuff I had bought to do some windows.  I use it to glue the brass capsule mount rod into the wooden plug, and to glue the wooden plug into the body.  I also use hot glue (available at craft stores) to attach the big film capacitors to the circuit board and to glue the felt to the wooden plug.  You could use the regular glue for those applications, I use hot glue because it dries quickly.

Mounting the XLR:  Throw away the washer and grind the points off the nut.  Also, the little tiny screws are just a bit too long, so you'll have to cut the tips off.  It's easiest to put in an uncut screw first to cut the threads into the plastic.

Grounding and Shielding:  The copper foil tape can be soldered.  It's used to connect the mic body to the circuit board, by making contact with the inside of the mic body and being soldering to pin 1 and the chassis of the XLR.  If you get a lot of hum this is probably the culprit.  However, I've found that you don't get a lot of hum even if the windscreen is removed, since there's enough mic body to stop a lot of hum.  You could experiment with soldering a ground wire to the windscreen mesh, but I haven't found it necessary.

Circuit board:  Between the schematic and the pictures you'll hopefully figure it out.  I use hot glue to attach the big green capacitors to the circuit board, but usually I've got everything else in place before I do that.  One of the pictures shows a test capsule – one of those little Panasonic capsules with the Linkwitz mod should work with the circuit.  I've got one with test clips so I can test every circuit board before installation.