Why does my express sound like FUZZ?

[fugezii]

I’m guessing that it screams now! I love these amps.

It sounds great now, Reasonable noise levels. For safety, I use a leakage protection switch to connect and wearing insulated gloves .
There is one more thing I don't understand.
Measuring the bottom case of the chassis, it has 36AVC, is this normal?

[sluckey]

Measuring the bottom case of the chassis, it has 36AVC, is this normal?

In respect to what? Are you sure it's not 36mV?

[fugezii]

Measuring the bottom case of the chassis, it has 36AVC, is this normal?

In respect to what? Are you sure it's not 36mV?

Sorry for the wrong description, forgive my English level.

I measured the aluminium case to the ground. It has 39.9vac, 2.13ma

Is it normal?

[pdf64]

The 0V circuit common (ground) of your amp should be connected to the chassis using a screw, nut, star washer and solder lug. Surface oxide can prevent a good connection so check that the connection’s resistance is 0 ohms with a meter. Don’t omit a star washer, as they act to cut into the metal surface, thereby breaking through the oxide layer.
The chassis must have a safety ground connection, so that the chassis is securely and reliably connected to planet earth when it is plugged into the mains wall outlet.
Obviously the screws / nuts for these chassis connections must be tightened to a high torque.

[wpaulvogel]

Quite shocking eh!

[fugezii]

The 0V circuit common (ground) of your amp should be connected to the chassis using a screw, nut, star washer and solder lug. Surface oxide can prevent a good connection so check that the connection’s resistance is 0 ohms with a meter. Don’t omit a star washer, as they act to cut into the metal surface, thereby breaking through the oxide layer.
The chassis must have a safety ground connection, so that the chassis is securely and reliably connected to planet earth when it is plugged into the mains wall outlet.
Obviously the screws / nuts for these chassis connections must be tightened to a high torque.

I rewelded the common grounding of the circuit and added a star washer. Finally, I found that a filter socket caused the ground wire to hang. Now the problem has been solved. The voltage from the aluminium shell to the ground is 0.001vac. Thank you very much for your help!