power cables' effect on power conditioner?

You must use a high current cable of heavy guage.

If your entire system is plugged into it its your most important cable.High gauge copper is best.

Ok, I get the importance of a heavy gauge cable from the outlet to the conditioner. I have an Audience Au24se cable that I can use for that. I have a LFD NCSE MKII+ integrated amp. I use  LFD Silicon Signature power cables for the amp and LFD Dac 5se dac. Although considerably less costly than the Audience the LFD cable gives a much better sound. But will the sound be changed noticeably by a different brand power cable in the chain? The LFD is not as heavy as the Audience.
Thanks for the info. Power conditioning is a new arena for me.

There is no risk in mixing brands among your power cables as long as the capacity of the cord matches the draw from the conditioner. So try and see what sounds best to you. My personal experience is that the cable to the conditioner is actually less sensitive than the cables from the conditioner, that’s assuming a conditioner that has some genuine power reserve/augmentation capability.

If your Audience PC is 10 gauge, it’s worth trying on the power conditioner. It has a low noise floor, but I wouldn’t call Audience a neutral sounding sounding cable.

Completely agree with @steakster.
Each PC in the chain has an effect on overall sonics.

Regarding power conditioners and amplifiers, make sure you choose a unit that is non-current limiting. IOW, a unit that does not affect the sonics or dynamics of a high current component.

During my experimenting with various power conditioners, I agree with folkfreak. "the cable to the conditioner is actually less sensitive than the cables from the conditioner" to the individual components.
Results may vary so experiment and see what happens.
I've experimented with the following; High Fidelity MC-6, High Fidelity Hemisphere, Equi=Tech Model 2Q, DeZorel G2 Mark II, and Core Power Technologies 1800.

Plus one for steakster. Try different cables, but high current capability is important for this application.

My experience is that the power cord to the conditioner has been my most important cord, bringing the greatest overall impact for my system's sound. This has been true with quite a variety of conditioners:  early Shunyata Hydra 8, Audience AR6, Audiodharma PowerWing, Weizhi PR-6, HB Cable Designs Acrylic and Marble units.  IME it seems that every component benefits from the qualities of that first cable (and I also agree that the power cords from conditioner to components matter a fair bit, too).
I am using a PS Audio P-10 regenerator now, and this is the first conditioner that doesn't seem to improve with some of my better power cords (e.g. going from an Elrod Statement to a Statement Gold, to a Diamond MB X2 made no difference to my ears).  However, going from a stock cord to the Elrod Statement was a nice improvement.  In all of the other above listed conditioners each cable move up was rewarding and worthwhile IME.

@lak. What was your experience with the 2Q?

@ptss, I like the 2Q very much and it does a very good job. Talking apples to apples in my opinion it functions better (sounds better) than my 1800, but of course its much better build, extreamly heavy but cost signifently more.

I am planning on running a dedicated 10 Guage steel shielded power cable from my breaker box to feed my niagara 7000.   

This cable claims to deal with harmonics - if I can find some others take 190 feet  since  they only sell 250 reels 

http://www.afcweb.com/mc-metal-clad-cables/super-neutral-cable-neutral-per-phase-or-oversized-neutra...

I wanted to terminate the run in a 20 amp IEC and plug directly into my power conditioner, bypassing the outlet and another cord.  Aside from code issues , has anyone done this ?

Any power cord cord will impact the sound of any gear you plugged them into. It’s how they impact the gears power supply and that is an unknown which is why you try before you buy.

@emailists , it was my understanding that steel shielded cable should not be used in audio applications. The link you provided states the use of this cable is for...

"Branch circuit and feeder wiring for computers, programmable controllers, electronic discharge lighting, office machines and other electronic equipment that introduce additive harmonic currents from non-linear switching loads"

Maybe you can enlighten me as to why this cable would be superior to 10 gauge Romex. 
I thought BX type cable and metal conduit should not be used from circuit panel to audio system.

I found mention of that steel shielded ac cable on another audio site but no one had actually used it.  They also have already aluminum cased version.  Would that be better?

In My application the cable will be in wall for for A foot or two from the breaker box then run on Wall or along the floor in mostly hidden areas.   That's why I thought steel encased cable would be advantagous.  I also just read about  VH audio Cryo treated romex.    Not sure which direction to go - I'd like to hear more about why steel or conduit should not be used.  

@emailists , I'm not an electrician or an EE. I think the issue with a steel shield or steel conduit is that it should never
touch the ground wire of the dedicated line or become grounded to the destination. eg, the circuit panel ground buss or a steel receptacle box.

If you are not consulting with an electrician, you could start a new thread about your dedicated line. Many  experts on the forum will respond.

https://www.southwire.com/commercial/metalCladCables.htm

This is from the company who makes Romex. Typically used in a commercial installation.
You could post your question about the best way to run your line and also ask about VH audio Cryo treated Romex.

@lak .  Thanks. I too find Equitech 2Q excellent and so it seems do all owners. They very rarely come for sale used. Very rarely; on any site.