Another thing, the TAD schematic specifies voltage at various points in the circuit, measured with DVM read to ground. At one point it even goes up to 390V. Now, if I do that measurement I will do my best to stay safe (clip one DVM to the chassis and tape the other lead to the end of a wooden chopstick) - but my digital multimeter is a cheap one, and the probes look like this:



My DMM is a Velleman DVM850BL (click for specs). Supposedly it can handle up to 600VDC, but looking around on the Internet I came across the concept of a "high voltage probe". Do I need a pair of those? Should I go out and buy them or just skip the measurement step altogether if the amp powers up and works?