Page 10
Copyright
2008 FiveFish Studios
www.fivefishstudios.com
SC-1mk500 Microphone Preamp Kit
SC-1mk500 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.
Follow this checklist during your construction.
STEP 1. Solder all 1/4-watt resistors and inductors 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. The 100K resistor is 100,000 ohms. )
R28 behind the Bourns potentiometer is a 100-ohm resistor.
R29 and R30 besides IC1 and IC2 respectively are 100K resistors.
STEP 2. Solder the (2) inductors L! and L2 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. Don’t forget Diode D6 located below the relay
(white box component).
STEP 4: Solder all IC sockets and the single Relay to the PCB. Make sure to mount all IC sockets in the correct orientation. (This
will serve as a reminder on how IC chips will be inserted.) TIP: Use masking tape to hold the IC sockets in place while soldering.
Also make sure the Relay is oriented in the correct direction. The “line marking” should be at the bottom.
STEP 5: Solder all ceramic capacitors to the PCB. These are the yellow and blue capacitors. The orientation does not matter.
Build Notes: C25 (33pf 50V) is unused.
STEP 6: 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 7: Solder all electrolytic capacitors. Note the orientation of where the (-) and (+) leg should be inserted. The unmarked leg
of the capacitor is the (+) leg. All (+) legs are positioned either to the right, or up.
Build Notes:
a. Capacitors C12 and C13 are non-polarized so their orientation does not matter.
b. Watch for the orientation of capacitor C18 and C19. Make sure there are no shorts under these capacitors. These
capacitors are power supply filtering capacitors.
c. Also make sure there are no shorts on capacitors C20 and C21 (0.1uf capacitors).
STEP 8: Solder the (2) 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 9: Solder the Bourns potentiometer. Solder the middle leg first, check alignment, and then solder the 2 outer legs.
IMPORTANT: Make sure you cut/snip the tab located on one side of the blue potentiometer. Cutting this tab will make the
potentiometer stay straight and perpendicular to the Front Panel as you tighten the nut.
