turntable speed control

The Phoenix does no AC regeneration, or lower the motor voltage after startup like the SDS. More noise.

This of course is also incorrect. The Falcon/Eagle are AC regenerative power supplies and they use DDS technology to create AC regeneration which has much lower distortion and noise as well as being hundreds of times more accurate than the PLL circuit the SDS uses (see link above).

The Eagle/Falcon also has reduced voltage output which is front panel programmable.

The Eagle is capable of 230VAC output so it works with tables worldwide. It will also work with 50Hz motors where the SDS does not. The Eagle/Falcon works with the RoadRunner tachometer to automatically correct for long term drift which the SDS cannot.

The Eagle also delivers more output power than the SDS:
https://www.youtube.com/watch?v=tt9AuTg3QXA

phoenixengr

Thanks for dropping in, pretty much sums it up.

I was looking at buying an SDS for my Prime, but after reading this and comparing the price ($525 for the Eagle vs $1399 for the SDS) it seems like a no brainer.

If the motor on the sds system is always turning the same speed the platter will not go faster because the bearing is warm. That's a load of hooey. And I think the affects of belt creep are also greatly exaggerated. You could always go to tape, silk, or thread if you are concerned about that. To me a a constant stable speed is always better than a changing one. 

The best belt would be a endless rubberized steel cable style belt like the old micro seikis. Quiet and they can't stretch. Micro did things right