Power Supply Noise Test Comparison (Strymon Zuma vs Tone City Substation vs Donner) 

This is a scientific test of the noise floor between these three pedal power supplies.
Strymon Zuma
Tone City Substation
Donner DP-2
Signal chain is
Guitar
Pedalboard
Amp
Rode NT1A
Behringer UMC202HD
No post production effects or boosting was applied to the audio.
No compression, no EQ.
I hope this is somewhat helpful.
Donner
1:36 SD-1
1:40 OD-3
1:44 OD-3 x2
1:48 Phase 90
1:52 Analog Chorus
1:56 RE-20
2:00 RV-6
Tone city
2:08 SD-1
2:13 OD-3
2:18 OD-3 x2
2:23 Phase 90
2:27 Analog Chorus
2:33 RE-20
2:37 RV-6
Strymon
2:46 SD-1
2:51 OD-3
2:54 OD-3 x2
2:59 Phase 90
3:03 Analog Chorus
3:08 RE-20
3:12 RV-6