Here is a quick article describing a low-noise power supply for low current applications. It’s simple, and easy to build. All parts are widely available and cheap. I’m using this power supply to power-up my RIAA preamplifier. It’s more that capable of delivering excellent results. Build one and try it for yourself.
First of all lets see the basic functional diagram of the regulator.
This is a quick entry to demonstrate a simple topology used in this ECC88 preamplifier. I’m using 7V heater variant – PCC88. It seems like the term “preamp” is not quite suitable here because the stage is actually a buffer and there is no amplification whatsoever. The schematic is shown below:
This is a very neat and nice PCB upgrade for Thorens turntables. It’s possible to use it with almost every other turntable that includes 16 to 24 pole synchronous motor.
The idea was to have a small PCB which includes both protection and power-off function. The PCB itself is a one-sided board with black solder mask on both top and bottom layers. I’ve decided to include optional drills for other capacitor sizes. This will make it possible to “adjust” the board for other Thorens models of even other turntable makes like Linn or Ariston.
Here is a handy LM317 constant current calculator/tool. It allows you to quickly calculate the set resistor and the heatsink (is needed).
Here is my circuit adopting the famous LME49811 amplifier front-end and ThermalTrakTM
transistors. This one is a rather conventional topology but implementing some tricks to improve the performance.
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