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Copyright
2008 FiveFish Studios
www.fivefishstudios.com
SC-1mk2 Microphone Preamp Kit
SC-1mk2 Assembly Guide
The general guideline in electronics assembly is to solder the smallest/shortest component first (resistors, diodes, inductors),
and solder the bigger/taller components last (ceramic capacitors, electrolytic capacitors, switches, etc).
The last step is inserting the IC chips into the board.
NOTE: The photos on this Assembly guide may not match exactly the PCB you received. But the instructions are still valid.
Follow this checklist during your construction.
STEP 1. Solder all 1/4-watt resistors to the PCB. The orientation does not matter.
Build Notes:
a. DO NOT SOLDER RESISTOR R31, R32. (These are marked as 2M2 resistors on the PCB. Leave blank.)
b. If you’re NOT using the Input Transformers, solder jumper wires for the transformer. See the dashed lines printed on the PCB
board. Solder 2K67 resistor for RLP. (located to the right of the transformer)
c. If you’re USING Input Transformers, leave RLP blank and solder 6K8 resistor for RLS (located to the left of the transformer)
d. DO NOT INTERCHANGE the 100R and 100K resistors. (100R is 100-ohms. While the 100K resistor is 100,000 ohms. )
R28 besides IC3 is a 100-ohm resistor.
R29 and R30 besides IC1 and IC2 respectively are 100K resistors.
STEP 2. Solder the (2) inductors to the PCB. The orientation does not matter.
STEP 3. Solder all diodes to the PCB (except LED diode, LED1). These include Z1 to Z4, and D1 to D9. Note the orientation of the
diodes. All diode bands should be pointing to the RIGHT, or pointing UPWARDS.
STEP 4: Solder all IC sockets to the PCB. Note the orientation of IC3 socket. Make sure to mount the IC3 socket in the correct
orientation. (This will serve as a reminder on how IC3 chip will be inserted.) TIP: Use masking tape to hold the IC sockets in
place while soldering. See photo on right.
STEP 5: Solder all ceramic capacitors to the PCB. These are the yellow and blue capacitors. The orientation does not matter.
Note. This capacitor is UNUSED. C25, 33uf/ 50V
STEP 6: Solder the jumper connectors, JP2. Make sure they are soldered straight up, and not crooked to the left or right. TIP:
Solder one leg first. Check if it is straight. Then continue soldering the other leg.
STEP 7: Solder the Transistor. Note orientation of the transistor. The flat side should be facing to the right. You will need to
bend the middle pin backwards to go through the hole.
STEP 8: Solder all electrolytic capacitors. Note the orientation of where the (-) leg should be inserted. The unmarked leg of the
capacitor is the (+) leg. All (+) legs are positioned either to the right, or up. Capacitors C12 and C13 are non-polarized so their
orientation does not matter.
Build Notes:
a. It may be more convenient to solder C18 and C27 last. These are the big, tall electrolytic capacitors located at the bottom of
the board, near the power supply pins.
STEP 9: Solder the Trimmers. Solder on leg first; check to make sure the trimmers are flushed to the board and straight. Then
solder the rest of the pins.
STEP 10: Solder the voltage regulators. It may be easier to attach the heatsinks to the TO-220 voltage regulators first before
soldering them to the board.
Build Notes:
CAUTION: The positive voltage regulator is labeled LM317. The negative voltage regulator is labeled LM337. DO NOT
INTERCHANGE THE TWO PARTS!!!
STEP 11: Solder the DPDT switch. This switch has 6 legs. You may need to adjust the legs and move them slightly left and right
for them to insert properly into the PCB. All (6) legs must be properly aligned for the switch to go into the PCB. Solder one leg
first; check that the switch is still flushed to the PCB. If everything is flushed, solder the remaining legs.
STEP 12: Solder the Bourns potentiometer. Make sure the component is flushed to the board. Solder the middle leg first, check
alignment, and then solder the other 2 legs.
