Tweaking preamp and amp combination

SMC is hard to beat. You have one, and upgraded, so you must have a pretty good idea what to expect. Hard for me having had a DNA to understand why anything else is even on your list, unless there's something you want to change. Surely you'll have more improvement for the $$ from SMC, and without the risk of changing the sound you have now. AR will definitely change the sound you have now. So is that what you want?

Why are you looking at changing the amp anyway? Seems to me its the best component on your list.

What aspects of the sound you’re currently experiencing are you looking to improve upon?

I'm using SignalCorp.com interconnects, power cord for amp, and speaker bi-wire cables. The phono stage tubes in
the SP9 MKII are Electro-Harmonix 6922 Gold. The WX-2 cross-over filter that I'm using is set at 75K.
Thus at minimum an M5-HP (If I could find one) may make an improvement.

When listening to certain vinyl recordings I hear distortion in high timbre vocals and cymbals where playback is too bright which from my understanding may be due to the recording's improper mix or lack of proper compression.

In digging deeper to my original inquiry, can changes in interconnects, tubes, crossovers, cartridge or amplification compensate for playback of recordings to make them more listenable if they may have been mixed improperly?

charkune your last paragraph is exactly where I would start.The right nos tubes can make a huge positive difference.EH tubes have a clear 'modern' sound.Experiment with different brands that are known for a touch of warmth in the upper mids.
When you find 'the ones' that get you most of way there,then move on to try something else,maybe interconnects next.Room treatments are something to consider too.

Hi,
i had an SP-9MKII and i do not remember it sounding bright, quite the opposite and it had a very nice phono section. Neither is McCormack a bright sounding amp.
What kind of distortion? clipping? Is your cartridge correctly aligned? loading? You get this distortion from vinyl playback so you should start there.