My DIY 5U Modular Synthesizer Power Supply

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My DIY 5U Modular Synthesizer Power Supply

Post by Danniielle »

Here's a few photos of the dual tracking, linear power supply I designed and built to power my 5U modular synthesizer. This provides very low noise +15, +5 and -15 volt rails. The +-15v rails are dual tracking and the +5v rail is derived from the +15v rail via a 78H05 regulator. I used good old 2N3055/MJ2955 transistors as the main regulators for the +-15v rails.
I also built the main cabinet and left wing cabinet for the synthesizer.

See the synthesizer HERE

This power supply has timed inrush current limiting on the main filter capacitors via series resistors which are bypassed after five seconds via a relay. I used a second relay to disconnect the rails if an over volt failure occurs.

Some of you may recognise the large PCB with the diode bridge, main filter caps, inrush limiting resistors and the timer circuit. I repurposed it for this project.

It doesn't require a great deal of cooling so I have the fan running at quite a low speed so it is practically silent. Finned heatsinks on the main regulator transistors aren't necessary.
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