Power Conditioners.

Stuff to help the power can be as simple as a ferrite clap on the zipcord AC wire to your DAC ($5.99 Radio Shack)
To several $10,000 devices..
I started with an Adcom power conditioner, then a Monster, then a better Monster.
Now I use a Furman REF20i ($3,500 list, I paid used, $1,500)
and a PS Audio P600 also bought used here.

Different devices have various ways they help. Far more diverse than cables.. A power conditioner is a device you need to try and see if that one is right for your needs.

My general way to help get through the wilderness is the say spend no more than 10% of your equipment cost on a conditioner. (not including cables)

Both my conditioners together at the used price I paid fall into this 10% rule.
So i suggest it as a rough guide on what to spend.

Like I wrote, conditioners come in a huge variety of devices, many of which do diffeent things to the power.
The best way to find out which is for you is to try them.
The Furman with "power factor" included are very good. And what I would suggest as a start.
Actually i would say anyone can dip their toes in with the $5.99 ferrite clap! They work on CD players.. DVD etc..

The Blue Circle Thingee is a effective PC for around $225. They are kinda ugly but if you can hide it behind your equipment like I do its not an issue. Google for reviews.

A number of questions to ask:
1. How much am I willing to spend? (Something to re-evauluate several times over this process.)
2. Is my budget determined by X% of the total cost of my current system, or, X% of the total cost of my imagined system 10 years down the road? Some folks recommend this approach (i.e., taking a certain percentage of the total cost of your system. I prefer to listen to how much of a difference the product appears to make in the overall sound, and let that guide the purchase -- to each his own).
3. Does the power conditioner use caps or coils? (such power conditioning methods have a reputation for restricting dynamic performance).
4. Am I going to try/compare 2, or 3, different products? (I"d investigate several brands, first, to narrow it down to the ones you'd actually try: never hurts to look for the "why" or "how" in the product, rather than just the "it does 'this' to the sound..." sort of presentation.

Power conditioning in the form of power cords is seriously worth considering too (or instead). By using power cords designed to condition the power, as a means of power conditioning, you'll be less likely to want to replace the power cords in the future, or purchase a stand-alone power conditioning unit, and therefore save money in the long run. There's also the added benefit that by using power conditioning power cords to condition the power—depending on the power cord—the conditioning will take place at the most vital location: immediately before the power enters the powered equipment (instead of X number of feet prior to it when using a stand alone power conditioning unit).

I'm wondering how long it will take now for the "power cords make no difference" crowd to chime in :)

Best wishes,

Aaron Knock
AK