DIY audio blog for projects, schematics, PCB's, designs, electronics, mods


ECC88 Preamplifier / buffer

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:


Thorens Power Supply Upgrade TD-150, TD-160

pcbThis 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.

LM317 Constant Current Calculator, Tool

Here is a handy LM317 constant current calculator/tool. It allows you to quickly calculate the set resistor and the heatsink (is needed).LM317_constant_current


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.

Simple JFET Preamp

A JFET preamp for beginners. Simple yet elegant. Low noise.

The following is an example for a very simple and high quality JFET preamp. You can use this to amplify a very low signal sources. FET transistors are usually not used independently in preamplifiers. In most of the cases they are paired with bipolar transistors.

simpe jfet preamp

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