Tweaking preamp and amp combination

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.

Your problem is not your amp, and I find it very curious that when you say you’re having issues with vinyl playback you don’t bother to mention what analog gear you’re using.  Why???  Sheesh. 

I've owned the 3A Sigs and the SP9 MKII (and MKIII).  Neither caused any distortion on my vinyl.   What did cause the distortion you describe was bad cartridge setup, especially zenith.  
The Electro Harmonix tubes were ho-hum IMO.  In the MKII I liked Telefunken ECC88 but in the more detailed MarkIII I liked the E88CC.  
The 3A Sigs were sensitive to cables for sure.  I had cheap Monster Powerline 2 and going to Acoustic Zen Satori reduced glare dramatically.  Also, reducing "midrange glare" is a function of the tweeter control, not the midrange control, so a heads up on that.  Good Luck!  

Thanks all for the recommendations.  I decided to take guidance to revisit my cartridge setup.  I found a more current document online and when thru the tonearm setup. I realigned the cartridge on my tonearm and reset tracking force. I then set VTA and azimuth.  These changes have corrected the issues I was facing with cymbals and high timbre vocals. 

I'm due for a tube replacement in early July on the pre-amp so next step will be to try a different brand of tubes.  Thanks again.