removing humming sound from effects pedals

im using windows 7 and audacity version 2.1.0
I recently switched from inputting my instruments through effects pedals through the 1/8th’ BLUE PLUG on the back of my pc, instead of the PINK PLUG which I had been using. I was told this change would improve my sound.
however, since making that change, whenever I turn on my effects pedals (delay, envelope filter, loop pedal) just through my amp (in other words, just playing, not recording on my computer using audacity at all,) the effects pedals create a loud HUMMING SOUND when I turn them on. this has never happened before.
could someone please tell me how to get back to how things were before I switched to using the blue plug (which I assume is the source of the problem) with no humming sound?
thank you for your help and sorry for the inarticulate description. it’s the best I could come up with.

The blue socket is “line-in” which is the correct one for devices like effects pedals, which have “line out” on them.
The pink socket is “mic-in” which is for microphones , it’s not matched for other devices.
Noise and distortion will occur if you plug a line-level signal into the pink socket.

What is the make and model number of the amplifier? Are these hardware pedals, if so the make and model number?

Is the amp or pedal attached to line-in?

Where is the hum heard - in the amp?


You seem to have a “mains” problems (something is not linked to the earth in your gear). I use a line 6 ux1 that is a specific hardware to record guitar but what you can do if you want to fix that with audacity is when you record something, record the huming sound, then select a section of the huming sound, go to effect, noise reduction, then click ok. Now select all your track and press ctrl+r or go to effect and do again noise reduction and click on ok.