Hello everyone, I bought some pcb to build a phono of audio note kit, I assembled everything tested and it is here with me that it sounds great, I have only a small problem, at the volume setting of my pre I hear a hum, which goes increasing with the volume, I used shielded cables, and separate transformer for the filaments.I use a gyrator instead of the inductor. I am attaching the schematic so that I can comment better.
