What does this mean?: If one of the hookup wires carrying power/B+ came loose from its soldered weld and touched either the chassis or something conductive to the chassis and the user then touched the chassis/unit with the power on they could get a significant electric shock. There are some seriously high voltages in this tube amp (like many amps of its topology) and the result could be lethal.
I would be surprised if the B- is not connected to the chassis as well as the circuit signal ground. Question is how are they connected to the chassis? Directly or through a low wattage resistance resistor? Or how.
If B+ were to short to chassis it would not matter one way or the other if the chassis was connected to the AC mains wall outlet equipment ground. There is not any electrical reference to the wall outlet equipment ground and the secondary windings of the power transformer.
I would hope the designer added some type of protection in the high voltage DC power supply to save it from seriously being damaged, If there was a B+ fault to the chassis B- of the high voltage DC power supply.
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The problem with the equipment ground contact, of the IEC inlet connector not solidly connected by a wire to the chassis, is there is not any protection from a possible electrical shock hazard if the HOT AC mains conductor came into contact with the chassis. Or it could be a bared spot in the primary winding of the power transformer to the iron core.
FWIW I looked up the amp. It looks like it was made in 2019. I though maybe it was wired using Double Insulated AC power wiring. I didn’t see any evidence that it is. Also worth noting a two prong IEC power inlet should have been used.
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