PC recommendation for McIntosh 501's

Putting the "final" touches on my current system which resides in a listening room that has dedicated circuits and extensive acoustic treatment.

Apart from adding a power conditioner to the front-end, the obvious next step would be to consider upgrading the pc's feeding my 501's.

I'm not looking to alter overall tonal balance, just want to let the 501's shine. In other words I'm looking for something as transparent (neutral) as possible. Any suggestions?

Here's my set-up:

CDP - Mark Levinson 390s (VH Audio Airsine / Gold Oyaide)
Preamp - Mark Levinson 326s (Shunyata Python CX)
Amps - McIntosh 501's (stock pc)
Speakers - Focal Micro Utopia Be (Audience AU24 speaker cable)
Sub - Revel Ultima Sub30 (VH Audio Airsine / Rhodium Furutech)
IC's - Nordost Valkyrja throughout
My vote is stick with the stock cable - I have tried a few and felt I lost that organic feel that makes the Mac's special.
Thanks Theo - I'll check out usedcable.com

Pops, I'm curious to know what cables you've tried as I have heard your "stick with stock" suggestion mentioned before.

If it helps, I'm open to anything in the sub $1,200 per cord range.
My thoughts mirror those of Pops. However I would like to add a few. McIntosh recommends to use their stock pc's on their amps and sources and concentrate on dedicated 20 amp AC for the amps, preamp and respected sources. Also invest in room treatments. If cables are still an interest invest in some good interconnects and speaker cables. Other than the stock pc's, Cardas GR, Wireworld Silver Eclipse, Kimber PK10, Kimber PK10 Palladian might interest you.

I reread your post. Try the Kimber PK10 Palladian if you are looking for a neutral sound. Articulate bass, better dynamics, free of grain and a sense of ease are just some of the characteristics of the power cord.
I use JPS Power AC-2's on my 501's.Extremely quiet black backround with superb bass and dynamics.I also use one on my C42 preamp as well.My quest for power cords ends with these.They're keepers.