For those that don't know I'd like to issue a safety warning on open connections like this, I am NOT picking on you personally mordy, it is just your setup here is a great example.
On the unmodified Vector extenders there can be upwards of
155 Volts exposed on terminals 5 & 6 and if you have the LD in EF92 mode on terminal 7 as well. (Obviously the same applies to the terminals on the bare B9A socket since that is where the wires terminate.)
If you are going to work with this kind of setup then do your work with the power off and don't forget that the capacitors in the LD will take a few minutes to discharge.
There is still dangerous levels with the power switch turned off and the mains cord unplugged if the amp has been on for a few minutes or more.
Try it for your self, while listening to some music, shut the amp off and pull the AC cord out if you wish just to see how long it takes for the music to fade out. These are the 250Volt capacitors in the amp discharging that is keeping the music playing and the voltage on the above terminals will still be present. I believe the music stops because the tube cooled with no heater voltage before the capacitors discharged all their reserve.
So if you have to touch or adjust anything with the power on then only work with one hand. Keep the other hand behind your back or in your pocket.
I you had a hold of the amp chassis and managed to touch terminal 5, 6 or 7 depending on the mode, it would be similar to grabbing the 110V Mains with a wire in each hand.
The LD transformer is rated for 100mA on the B+ line and referencing Charles Dalziel's chart, you are past the point where you can voluntarily let go.
So seriously take heed of this warning with these open point to point connections.
I really don't want to see anyone get hurt and If this warning makes just one person who is unaware of the possible dangers take some precautions, then that is good.