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 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.
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.
We have completed this module this week. It is a custom build by order of a customer. The module has many specific functions. It can be used for speaker protection, speaker delay, toroid soft start and others.