Do I need an SUT w/ an EAR 868?

It depends on the output of your cart and the total gain of your system. KAB has a gain calculator on their web site.

EAR makes some of the best phono SUT's on the planet. Not sure why you'd try anything else. In fact, your 868 may have a SUT already in the signal path which is what might be causing the hum... a sut connecting to a sut...

I'm with Swampwalker, what cartridge, output are you using?

I have a EAR MC4 SUT...it's a killer good SUT. This might be one of the very few instances where the wonderful bob's devices sut is a step down from the sut you already have built in...

maybe one tweak to far ;-)

Jfrech.. I'm using a Cardas Ruby 3. Output volt 0.34 mV at 3.54cm/s. Impedance 38ohms.

I may agree...one tweak for tweak sakes only! Recommended by a trusted dealer. But perhaps one step too far.

Thanks