Optonica SM-4100 Power Supply

The power supply is very simple in this amplifier. You have a split rail voltage supply labelled B+ and B- on the PCB. These Nichicon capacitors seem to be working fine all these years.

There is negligible ripple in the power supply; however, this amp is one of those worth modifying with upgraded capacitors. In my case, I have decided to keep this one in its original state.

Here is the popular and well-known BA40 Bridge Rectifier.

Here is another look at the Nichicon capacitors.

Although the power button is at the front, the power switch is at the back of the case. Hence, they had to use a metal strip to connect the two together.

Here is the mains power switch.

This is the mains transformer with a centre tapping.

It seems to be very robust with copper shielding.

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