Some spend more time perfecting than listening and that is fine.
So for that crowd this is the place to go http://arsc-audio.org/journals/v20/v20n1p14-23.pdf
My fellow blogger gave us some praise on the merits or curves etc…so this will let you set your rig to get get best from the older black ones.
This year after finishing the we13a I will be building a mono phono stage to take care of these tedious details. Drop the chrome zanden and Emt packed with off the shelf capacitors fancy knobs etc….and stay real.