• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Power On Indicator Light

pengboon said:
Is there anything bad to have a AC power on Indicator light (operates on AC) on the equipment, or is it better to have a LED (operates on DC)? I know it's probably best to have nothing, but just for interest sake. :)

No. As with anything else carrying AC, keep it away from sensitive, low level, circuitry. Indicators are most helpful if you split the heater power from the HV, as when using a SS power supply. It's most helpful to know if the HV is on or not.
 
Thanks for the replies everyone. I guess for tubes, it would be quite easy to tell. Don't we all love the glow.

I guess my point is, AC indicators (rated at mains voltages) are easy to implement (just 2 wires), almost the size of a LED, and not that much difference in price but seldom I see anyone using them.

Just food for thought anyway :D