HC-05 and annoying pulsation

maybe my bad luck is that there is a wah wah between the pedals and notoriously in the circuit of this stomp box there is an inductance, as in the picture below

https://medias.audiofanzine.com/images/normal/vox-v846-wah-wah-pedal-441397.jpg

I desolded the HC-05 led but the pulse remained. I then powered through this https://www.parts-express.com/calin...18v-guitar-effect-pedal-power-supply--245-100, which does not have real isolated outputs, because they have the common mass but at least they are filtered one by one, and I powered the stomp boxes separately, all at output at 100mA, except the Zoom that absorbs 500mA and connected it to the output 500 mA. At this point, I did converge the power supply ground on all the enclosures, and I got the absolute silence but it happens ...

if I turn on the wah wha (bought new and I keep it with the potentiometer closed, I hear a hum and if at the same time I turn on the booster (made by me) that is after the wah, the hum disappears as if the noise loses inside booster, after which there is the amplifier. Here, if I could remove this other hum, I would be more relaxed

mauros said:

I did converge the power supply ground on all the enclosures, and I got the absolute silence but it happens ...

Click to expand...

Good. As I expected.

mauros said:

if I turn on the wah wha (bought new and I keep it with the potentiometer closed, I hear a hum and if at the same time I turn on the booster (made by me) that is after the wah, the hum disappears as if the noise loses inside booster, after which there is the amplifier. Here, if I could remove this other hum, I would be more relaxed

Click to expand...

Keep chasing the grounds...

I also removed ground from wah's power supply but unsuccessfully

mauros said:

I also removed ground from wah's power supply but unsuccessfully

Click to expand...

Why?

eventual ground loop ... it works the same because ground gets it from the cables too