Review on 🔍 Nobsound Vacuum Amplifier Current Tester: Accurate Measurement for Audio Devices by Evan Haynes

Keyhole extended on one side to allow current tube to be inserted into probe per contact. It looks like it's about to hit! This damaged my amplifier. Fortunately, this only resulted in a burnt screen resistor and damage to the tube. I'm good with a soldering iron and replaced the resistor and now the amp works fine but the board is charred and my 6550 pair is just a tube now. You can rate this to see how much they cost. Madness to say the least. Don't skimp on test equipment, even something as simple as a displacement probe.