If it’s been serviced, I’d be surprised if they didn’t catch a bad cap? How long after you turn it on, does it pop?
Also, the DBX unit is right under the table. Have you tried moving it further away? Maybe the cartridge is picking something up from the unit?
I’ve listen to the pop several times now. It sure sounds like a static discharge to me. It builds up and then releases as a pop. It sounds like a Zerostat gun?
When an amp clips, it cuts the top of the waveform off. Here is an example of amp clipping:
https://www.youtube.com/watch?v=SXptusF7Puo
Much different sound than your pop.