Headphone socket wiring / schematic

[mcandmar]

That sounds like a very bad day.  I will resist the urge so..

[Loquah]

Is there any technical reason why you shouldn't switch the impedance board while the amp is running?

The manual for the impedance boards states "UNPLUG AMP BEFORE SWITCHING!", however is that just a safety warning to discourage people from poking their fingers inside a live amp, or is it ok to lift the amp and switch them with something non conductive?

Yeah, there's a good chance that you'll zap yourself while you reach under there.  On top of this, the zap will cause you to drop the amplifier, and it may zap you again on its way down.  (Don't ask how I know)

LOL and ouch (physical and pride)