KR4DIO

External Power Supply for Technics SL-1200 Turntable

photo of modified technics sl-1200 turntable

My dad has been modding his Technics turntable to make it less DJ and more audiophile, so in addition to removing the pitch fader and cue light, he also wanted an external power supply. This is apparently a pretty common mod, and other than the box, I was mostly able to put it together using parts I had laying around.

photo of technics sl-1200 turntable and external power supply

The main benefit is just moving the transformer out of the turntable, which should significantly lower the noise floor. I re-used the stock transformer, adding a 1N4007 diode bridge and a CRCRC filter made up of 3300μF caps and 10Ω resistors. A heavy umbilical cable carries the rectified and filtered DC power to the turntable, where it’s fed into the old rectifier’s position.

Next step: Replace the main 18v regulator with a low-ripple LM317 circuit.

external power supply schematicSchematic

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