Turntables and power conditioners?

You don't need them. A purpose built controller for your specific turntable is a big plus, however.

I have an SME 20 here, so I'll take a closer look at how it works. Meanwhile, I will revise my earlier post by saying that it all depends on the turntable you own.

If your particular turntable doesn't have a controller that regenerates power, maybe a power conditioner is in order. Otherwise, I cannot see any benefit.