Sparks at 62kV on the bias.

Turned it down, turned it back up and got a spark at 60kV.

Now up to 63kV, no sparks so far (5 mins). Left EE @ -3100V and EZL @ 28.5kV

There is the sound of a low level continuous discharge, like HV power lines, and a very strong ozone smell coming from the HV duct that sticks into the cage and carries the cables from the HV rack. Also seems to be present near the EE insulating standoff. Can't see anything though. Maybe just moisture in the air? Starts at 55kV on the bias, does not change with EE voltage.

Turned EZL up to 29kV, bias stable at 63kV for 11mins.

Sparks at 63.6kV in the EE spark gap, EE @ -3.1kV.