Brian Powell Audio

MC1

This PCB was produced from 1978 until 1981. It was adequate in terms of noise but had several shortcomings. It was expensive in parts and labour. It was hardly stable at HF. It picked up RF quite badly.

In FEB 2024 I have reworked the values for the MC1 and it works extremely well on the LTspice simulator.

DC re-bias the ensure all devices within range, adding a DC load to the array stops excessive voltage drop across the feedback arm:

The .asc file above is for the technically minded who would like to run the file inside the LTspice program

The noise can be lowered by using low Rb devices but below the value of the sharing resistors (22R) there is no improvement to speak of see Ultra low noise amplifiers (dicks-website.eu)