MW/LW Loop - transformed

I went to pick up RF transformers today. When inserted both noise and signals are attenuated, but it looks like the S/N is somewhat better.
The antenna was still located in the noise field of the shack, so I am not too surprised. 
Time to connect a longer cable (still indoors) to test the loop a bit away from the shack with all its computers and SMPSs.
The weaker signals may be due to a different impedance match of the receiver through the transformer to the loop.

Moving the loop further away from the shack noise, about 3 - 5m, offers a considerable reduction of the noise level on LW. The RTTY station on 138kHz is now essentially noise free, i.e. I estimate it could easily be demodulated Signal is about S6, and noise is down to about S1. Another RTTY signal on around 133kHz is now clearly audible, and one on about 147kHz - previously drowning in the noise - is now quite strong. That was not the case with the loop closer to the shack noise.
MW is not so much better in that respect, so maybe too many turns still create too much stray capacitance. MW is better, but a considerable noise level still exists on large parts of the band, mostly a harsh hum with many overtones, probably from SMPSs.
Is it possible that I should use fewer turns to optimize the performance on MW? One more thing must be tested before testing the loop outside, and about 12-17m from the noisy shack - and 10 - 20m away from other potentially noisy houses.
Enough experimentation for now. More in the week end. Electrostatic shielding should be tested to see if the S/N can be further improved.