Flipping record causing series of loud pops

Sorry, have never heard of a tube amp causing this issue. I’d say it is more likely a major build up of static electricity at the turntable platter. Maybe try zapping it with a zerostat. Is turntable grounded properly? What mat are you using? Felt can add lots of static. A leather mat works wonders...also the cleaning of a record while on a spinning platter can add lots of static, especially If using something like the old discwasher d4 system. The audioquest carbon fiber record brush seems to work well. 

Definitely static

Basic things!   
Baloney.  I never mute my phono in between.  There is no need to if everything is connected (grounded) properly.
If it wasn't static before it isn't now.  Doh.

If it is static electricity, you will feel the hairs on your arm raise when you lift the record off the platter no matter which phone preamp you're using. If this is the case, deal with the static discharge with one of the suggested solutions. Less likely, it's a grounding issue on your tube phono preamp.  Either way, get in the habit of using your mute button before cueing your tonearm down or up. That's what it's for and your amp will thank you.

It is an interaction between the phono stage and static electricity from removing the vinyl it is probably sensitive to this and some gear is more sensitive than others to static.