I’m pleased with the big reduction in hum level by removing the original built-in transformer and bridge rectifier and then using a toroidal transformer with an Ebay Chinese rectifier/capacitor board. It required a bigger box too. Hum level is so low as to be inaudible now even though I have increased the overall gain to give an output similar to CD. I also changed the original mica cartridge load cap with a polystyrene one and added a second switchable one to sum to it if required on each channel. Also, this circuit needed DC blocking caps on the output which at best is around 100mV...this value does vary quite a bit with different samples of LM4562. I have also included a series and discharge resistor on each side of the O/P caps as seems to be the norm. Sound quality really is superb and totally transparent using my Ortorfon VMS 30 Mk2 (fine-line stylus). The transformerless late board is now available shown below
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