Converting unbalanced direct outs to balanced

[psb_87]

Signal goes from IC4 out (impedance like 0R), then goes through R87 22R to direct out.
So output impedance is 22 + 0 = 22 ohms.

Remove the output jack socket ring / sleeve connection, solder a 22 R resistor between ring and sleeve, then you have impedance balanced out

Thank-you very much, a perfect answer.

 

[Newmarket]

Would it be this one marked in green?

I saw this over the weekend but wasn't logged in and couldn't see the schematic.
Yes - the 22R is the 'build out' resistor and is the resistor to 'duplicate' on the cold side.

Arguably it should really go to signal ground on the channel pcb rather than the connector shield but it may not matter / make a difference - depending on how the desk is put together. 'Pin 1' issue etc...
Also there's an argument for replicating the coupling capacitor but commercial implementations (eg on several Soundcraft desks) often don't bother with that and go with simple resistive balancing. The electrolytic should be large enough that it 'disappears' at audio frequencies anyway.

Summary - go with the simple resistor  to screen balancing outlined and check the results.