Pearl Box Plans by the Jolly Roger
The Pearl Box:Definition - This is a box that may substitute for many boxes
which produce tones in hertz. The Pearl Box when operated correctly can
produce tones from 1-9999hz. As you can see, 2600, 1633, 1336 and other
crucial tones are obviously in its sound spectrum.
Materials you will need in order to build The Pearl Box:
C1, C2:.5mf or .5uf ceramic disk
Q1.....NPN transistor (2N2222 works
S1.....Normally open momentary SPST
S2.....SPST toggle switch
B1.....Standard 9-Volt battery
R1.....Single turn, 50k potentiometer
R2..... " " 100k potentiometer
R3..... " " 500k potentiometer
R4..... " " 1meg potentiometer
SPKR...Standard 8-ohm speaker
T1.....Mini transformer (8-ohm works
Misc...Wire, solder, soldering iron, PC
board or perfboard, box to
contain the completed unit,
Instructions for building Pearl Box:
Since the instruction are EXTREMELY difficult to explain in words, you will
be given a schematic instead. It will be quite difficult to follow but try
it any way.
(Schematic for The Pearl Box)
! ! \
C1 C2 \
! ! +
+ + -----+T1
! b c-------! +
! Q1 ! +-S1-
! e-----S2---+ ! SPKR
! ! ! +----
! B1 !
! ! !
!R1 R2 R3 R4!
/\/\ /\/\ /\/\ /\/\
+--+ +--+ +--+
Now that you are probably thoroughly confused, let me explain a few
minor details. The potentiometer area is rigged so that the left pole is
connected to the center pole of the potentiometer next to it.
The middle terminal of T1 is connected to the piece of wire that runs down
to the end of the battery.
Correct operation of The Pearl Box:
You may want to get some dry-transfer decals at Radio Shack to make this
job a lot easier. Also, some knobs for the tops of the potentiometers
may be useful too. Use the decals to calibrate the knobs. R1 is the knob
for the ones place, R2 is for the tens place, R3 if for the hundreds
place and R4 is for the thousands place. S1 is for producing the all the
tones and S2 is for power.
Step 1: Turn on the power and adjust the knobs for the desired tone.
(Example: For 2600 hz-
Step 2: Hit the pushbutton switch and VIOLA! You have the tone. If
you don't have a tone recheck all connections and schematic.