Thanks for the advice. I will look into fuses and DC detecting.
Anyway, my DC offset is 0.7mV on each of my Gainclones with the input shorted and connected. They both start at around 5 - 10mV for the first few seconds after switch on, but slowly dwindle away.
When attaching the scope to the output, there is slight noise, and when a speaker is attached, there is a slight hiss, but there is no hum. This was achieved with the ground blocking circuit which AndrewT recommended. (10R resistor paralleled with 2 back to back diodes between main earth and power ground)
Anyway, my DC offset is 0.7mV on each of my Gainclones with the input shorted and connected. They both start at around 5 - 10mV for the first few seconds after switch on, but slowly dwindle away.
When attaching the scope to the output, there is slight noise, and when a speaker is attached, there is a slight hiss, but there is no hum. This was achieved with the ground blocking circuit which AndrewT recommended. (10R resistor paralleled with 2 back to back diodes between main earth and power ground)