Thom,
Don't forget he's running through stepups. Resistor values are different than with an active MC phono stage and, as Swampwalker mentioned, tiny changes are (should be) audible.
Stepups create more complexities than active MC gain stages (turns ratio? primary side loading? secondary side loading? both?). We spent years tuning stepup loading, including pairing parallel resistors to achieve intermediate values. The quality/type of resistor matters too.
Suggestion to Artemus: try some Riken Ohm resistors in place of your cheapies. If you get the right value they might remove some edge without rolling off the highs.
****
Regarding amps and power (wattage):
Maril555 gets better performance from a 150wpc BAT than from a 90wpc p-p amp. OTOH, we get better performance (despite more difficult speakers) from a 57wpc p-p Doshi/Lectron than from a 240wpc SS MF-2500A.
There's no reason to doubt these reports, so there's no correlation between these improved performances and increases in total wattage (for the reasons Lewm explained). In a typical home environment, speakers like Artemus's or even our B&W's simply do not use the full power output of a 57wpc amp, never mind 90, 150 or 240. The improvements must be attributed to other factors.
One reason the Doshi/Lectron so easily outplays the c-j is its massively overdesigned, overbuilt and well isolated power supplies. Power supply modulation by dynamic, complex signals is a major source of sonic congestion, smearing and harmonic distortions. Zero feedback is another, as Lewm mentioned. With speakers like these we don't need more power (watts). All you get from more watts is more SPL's, and we can easily surpass 100db in our room with the power we have. What we need is an amp with a very low noise and sound floor, that supplies current instantaneously and which is not prone to going muddy when the going gets tough.
I suspect Maril555's BAT is simply better at these things than his old p-p amp. The fact that it offers 150wpc vs. 90 is interesting, but not relevant with speakers like these.