Which cable has most impact - IC, Spkr., power?

I will suggest your power cords. Digital unit 1st, then the pre, finally the amp. Starting out with the least possible distortion will give you the best bang for your investment in my experience.

I agree with Nasaman....my experince the power cord`s and ic`s made the most difference. I usually keep my balanced interconnects between the amp and preamp and speaker cables the same. Changing the power cords and ic`s on my sacd/cd player gives the system a whole new character. Changing the amp power cord and TT ic`s have the same results.

I feel that interconnects are most critical, closely followed by speaker cables. Power cables are the least critical in my systems but I always start with a 20a dedicated circuit - sometimes multiple 20a dedicated circuits.

my 2 cents

happy listening!

...like I said, nowhere!

My experience is that everyone's components react differently to cabling, as is everyone's power quality. Never has YMMV been more true.

For me Power Cords make the biggest improvement
with my Krell gear. I am suspecting that high dollar
powercords filter noise out of the A/C without suppressing
the current flow (like those nasty monstercable power
conditioners). But no matter the reason all I can say
is power cords can transform a system more so than
anything else in my experience.