The Salt Shaker Form
Pop off the plastic end and dump out the salt. Remove the outside foil by
filling it with water and pouring it out. After a five minute
wait the foil will
remove easily.
Let it dry out completely before using it.
I blackened the cardboard with shoe polish for a nicer look.
Use a marker and mark two
dots 7/8" apart centered on the metal plate for drilling the
Tee-Nut holes. This way the Tee-Nuts
don't overlap and will rest on the metal rim shoulder.
Drill two 1/8" pilot holes at the marked dots opposite one another. Then enlarge them using a 5/16" drill
bit.
Epoxy a piece of Popsicle stick on both sides of the holes. This will
make the Tee-Nuts level with the metal lip. Slip the two
Tee-Nuts in place resting on top of the Popsicle sticks using epoxy to
secure them in place. Do Not Get Epoxy on the Screw Threads!
One brass screw is used for very fine adjustments of the octave
widths. The other brass screw has a ferrite choke "rod" on the
end for more rapid tuning.
The ferrite rod mounts on the brass screw using a plastic tube as seen in the above picture.
How to Wind the Coils
Lightly press a 2” ( 5 cm)
strip of the 1/2” (13 mm)
wide foam mounting tape 7/8" from the metal end.
Mount your wire spool on something to keep the dispensing orderly.
Start your first wind about
1" from the metal end of the salt shaker form so the mounting
bracket has room. Place your first wire under the foam
or under a piece of tape, this is A4. You want to leave about a 5"
length of wire for connecting to the board.
Avoid overlapping wire turns and space between
them, keep your pulling firm.
Wind 60 turns from this 1" (25 mm)
distance from the metal
edge, using #26 gauge wire. 60 turns = 1" in wire wrap width.
Place tape over the wire wraps just before the foam to secure the 60
count wrap. Twist out about a 5" tail for the A3 center tap. Keep the
center tap from untwisting by place another piece of tape next to it.
Continue wrapping 33 more turns of wire. Total width of 93 turns = 1.59" Secure the last wrap with tape then tape over all the wire wraps
to hold them in place.
The last wrap is the A1 on the open end of the coil form, leave an extra
6" of wire length for connecting.
High room temperatures will make Scotch tape gooey and it will come
loose.
The 5" twisted length of wire is the
A3
center tap.
Secure the last wrap with a small piece of tape then place one 2"
length across all the wire turns.
Screw in the two brass screws, one from the inside of
the coil and the other the outside. In other words the metal plate side
Tee-Nuts should have a screw head on one and the other is the screw
threads. Leave 1" on both beyond the Tee-Nut sticking out, they must turn freely!
Mounting the Coil
Mount the coil bracket to the board, then use a 1/2"
piece of Velcro tape inside of the bracket.
Mount the
L2 coil to the board, slightly different positions will create
different wave shapes.
Note:
Orientation of the L2 coil is critical. On the board the coil metal side must face
towards LED 2.
The coil metal side is A4 and the open end is
A1. A3
center tap is 33 turns from the open end.
Cut the tip off of the A3 twisted wire pair so you can pass it through
the A3 board hole. Both wires will reconnect at the A3 solder pad.
From L2 take each wire and pull it through the correct board
holes completely. Cut the wire about 2"
( 5 cm)
from the bottom of the board.
Take a butane cigarette lighter and heat up the tip of the wire, the enamel burns off nicely. Clean the tip with one of those green kitchen scrub pads. Also
you might "Tin Solder" the tip to make certain its clean.
Now back the wire slack out its hole and solder the tip to the board.
Note:
Do not bunch the coil connecting wires together, leave them loosely spaced to the board holes.
The coil wire connections will be your weakest link,
use care when cleaning and soldering.
It is time to do Tuning the
Coil Oscillators (This is the
most exciting moment!)
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