Hello everyone ,
So up until now I was using my pod through my Combo's current preamp , which means i used the MONO output from the POD to the input of the combo amp without bypassing the preamp section.
Now I've decided that i'd like to bypass my combo's preamp , and for that I learned that you need to use something called the 4 cable method , though I did try some trick since i don't have 4 cables at my reach right now , by taking the guitar , putting it into the GUITAR IN on my Pod and plugging the MONO output from my pod to my Combo's Effects Sent loop. as for now it looks like it's bypassing my combo's preamp but at the same time , unlike before there's a very annoying static noise , quite bassy , it's mostly noticible when i don't play. when i turn the volume on my amp or on my pod or on my guitar all the way down the noise doesn't go away , is that because I didn't close the effects loop with the return and left it open so theres something hanging and causing some grounding issues or something which brings this annoying noise?
So I guess at the bottom line my question is , would using the 4 cable method solve my problem with this irritating noise or what i did with only two cables without closing the effects loop isn't the cause of that noise?

Thank you very much in advance!
You want to plug the output from the POD into the RETURN on your amp.

Guitar -> POD Guitar IN -> Left Out -> FX RETURN.

Also there is an option on the POD to select different output modes (Combo Front, Combo Power Amp, Stack Front, Stack Power Amp), play around with this. When I use the POD in this configuration I usually set it to Combo Power Amp.
Changing the settings from combo power amp to studi/direct doesn't help , It still makes the noise , i've realized the noise comes from my computer specifically since it doesn't occur if i plug my phone to the amp for instance. so i assume i should just give up on plugging the pod to my pc while playing.