You pretty much have it! Mini jack to stereo RCA's, plugged into the input of the Eros. Ideally you would run the signal through a reverse RIAA circuit, but straight through gets the job done too! Turn the volume all the way down on the music source. I usually hook the Eros output to my my pre, turn the phono, pre and then amps on. With all of the amplification on, preamp at your normal listening level, slowly ramp up the volume on the music source to just a comfortable listen level. If you are running OS tubes, put the stock tubes in for the burn in!!
The music will be distorted. Not to worry, it is just the lack of phono EQ. Once the music source level is determined, I note it. Then I can run the burn in signal in subsequent sessions without turning on the amp & pre. No need to listen after that!!
Yeah the "Oh Wow! /Oh $#!T /Oh Wow!" cycle is always exciting!! Be patient!!!
Cheers,
Geary