Center-tap Choke

[SonnyOneness]

The extra voltage on one side is caused by the voltage across the choke adding to one side and subtracting from the other. There is probably not much point in getting to the bottom of the issue, as the choke is not the best solution for your original aim anyway.

Drop the choke, and add a mains filter. In addition, add some proper grounding arrangements.

Yeah, maybe i should get rid of it, the increase in bass dynamics and headroom might just be in my imagination too, hehe.

Anyway i did test two other inductors (one air-core), same "problem". It's just strange, this should not happen at all, especially not with an air-core inductor.

The unbalance does get stronger/wider with increased inductance of the choke in place..

 

[DF96]

Yes, exactly as expected. All that counts is the inductance, not the core material. The perceived increase in bass dynamics could be your imagination, or it could be the choke interacting with the capacitors to form a resonant circuit which will raise the PSU output impedance and muck up the amplifier bass response. A poorer (i.e. less flat) bass response can sound better, depending on your musical tastes and what you are used to listening too. Some systems deliberately boost some frequencies. Its not hi-fi, but some people prefer it.