Caledonian Audio Phono Classique, Assembly Manual

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R7 is there to enable you to lower the voltage (if
necessary) before it gets into the voltage
regulator.
If you find that the later stage that the voltage
going into the regulator is too high (perhaps due
to local fluctuation of AC voltage coming into
your property) and the regulator is doing too
much of work ramping it down to 12VDC, then
you can ease the work of the regulator a little bit
by lowering it before it goes into the regulator.
However, for now, you can just use a wire-link.
Figure 2 Resistors on the power supply PCB
2.1.2 Capacitors
Once all the resistors are done, move on to the capacitors.
Please note that ALL electrolytic capacitors have to have the correct polarities
on the PCB. So, before soldering them onto the board, make sure that they are
correct. The electrolytic capacitors are:
•
C1
•
C2
•
C3
•
C4
•
C5
•
C7
•
C8
•
C9
•
C11
•
C12
As usual, follow the drawing on the PCB silkscreen which indicates the
polarities of the capacitors. Place and solder other capacitors as well.
2.1.3 Diodes
Please make sure that you get the correct polarities for:
1. D1, D2, D4, D5 – these are Schottky diodes in TO-220 format which form
the rectifier for the circuit. Follow the drawing on the PCB silkscreen
2. D3, D6, D8, D7 – these are again Schottky diode but in the normal DO-
15 format. They form the rectifier circuit for the 12VDC supply. Follow
the drawing on the PCB silkscreen
3. D9 – a standard diode to raise the 12VDC regulator by 0.6V in relation
to zero volt
Figure 3 Power supply PCB with resistors, capacitors and diodes installed.
shows the power supply PCB with some of the parts installed.