High capacitance power supply with noise filter for the modular high end audio amplifier system

Project presentation

Abstract

The power supply presented here is part of my modular audio amplifier system. This is an improved version of the medium size low noise power supply for the modular high end audio system. The power supply presented here has higher capacitance, while retaining some of the noise filtering of the low noise power supply.

Design presentation

Design considerations

The design is mostly the same like the medium size power supply for the modular high end audio system and the medium size low noise power supply for the modular high end audio system, but with an additional storage capacitor per supply. When I added the huge toroid inductor to the low noise power supply, I wondered whether I could instead squeeze another large storage capacitor on the PCB. Finally I succeeded, but had to rearrange a lot of components in order to make it work. Once the huge inductor was gone, I immediately missed it and found a spot to squeeze in a smaller one. While the inductors used in this design are very small, they still form a low pass filter with roughly 500Hz cut off frequency. The cut off frequency of the low noise power supply is roughly 130Hz. As always, compromised need to be made. I believe this is a good one.

Schematic

Assembly

Cost

Here is the cost breakdown of the module:

Part Quantity Cost p.p. [€] Cost total [€]
Storage capacitors 6 13.00 78.00
PCB 1 10.00 10.00
Rectifier diodes 8 1.00 8.00
Cage clamp terminals 24 0.25 6.00
Small capacitors 12 0.50 6.00
Inductors 2 1.00 2.00
Heat sinks 8 0.375 3.00
Resistors 14 0.15 2.00
115€ incl. VAT

Of course, the high capacitance power supply is more expensive and this is because it features more storage capacitors and those are the most expensive components on the PCB. However, the increase in capacitance results in an overall performance increase and the relative cost of all other components is lowered in comparison.

Summary

I find that this revision of the power supply is the best compromise in terms of size, performance and cost among all power supplies presented so far. Each of them is optimized for different applications and this one is balanced in the middle.