My Bellari EQmade pops whenever engaging or disengaging the EQ or when bypassing it BUT that’s how it works courtesy of Bellari. My Lokius I’d dead quiet, no noises at all. I would reverse the cables and see if it still pops. That will tell you if it’s the EQ or the preamp.
It’s for that reason that I have not listed the Bellari for sale. I liked the frequency’s they chose compared to the Lokius but don’t want to deal with the complaints about the noise when it turns on or off.