How do you know if you need a power conditioner?

I presently have my audio equipment connected to a dedicated line - is this enough? How does one know if you need a power conditioner? Are there symptoms? Does a power conditioner always improve the sound - or only in certain situations? Is there any way (short of sophisticated electronic measuring tools which I don't have) to tell if your power is relatively clean or dirty?

Thanks in advance.
I would have to say that you know if you put one in and then take it out and the sound worsens. That's about it. As the Brit hifi mags like to say, you've got to suck it and see. Happy listening!
I have had terrible results with all power conditioning, from the cheapest to most expensive. Nothing I have ever put in my system did good, only harm.

If you live in a high rise and share electrical with 200 other peoples TV's, computers and AC units, perhaps power conditioning is better than crappy power. In most residential homes I would bet that multiple dedicated lines and attention to cabling will get you where you want to be.

For my own system I went with fourteen dedicated lines and star grounding. As crazy as that might sound, the entire rewire job by one of the finest electrical contractors in town, replacing EVERYTHING from the power pole to the wall outlets (including a new trans socket meter) cost less than $4K.

There are AC cords that cost that much. Make no mistake, I AM FOR high end power cords, but before spending on conditioning and cords, the electrical should be as solid as you can make it.
1.) If you can, put in a dedicated circuit(s) first. You need a power conditioner if you can't put in a dedicated circuit(s).

2.) If you do 1.) then test the line voltage at different times of the day and night to make sure it stays inside the 118 - 122 Volt range. If it goes above or below, you need a power regenerator (which usually includes a conditioner)

3.) If 2.) shows proper voltage, but you still have noise on the line (from God knows what . . . we won't go into that now) you might need a conditioner, or a balanced power unit, but not necessarily a regenerator.

To recap, there are three different types of, let's call it, "power treatment."

A.) Power conditioner -- mainly provides noise filtering and some amount (usually not enough) surge protection. There are some additional bells and whistles available, such as Cable TV cable isolation to prevent ground hum from that.

B.) Power regenerator -- takes the AC from the wall and "fixes" it so it comes out nice even constant 120V, 60Hz.

C.) Balanced power unit -- takes (regular +/_) 120V to 0V AC and turns it into +60V to -60V AC which results in natural noise cancelling within the powerlines themselves.

Two or three of these devices are often combined within the same unit. However, even if you need all three, it often makes more sense to separate them.

So if you are getting good constant voltage with accurate 60 cycle power from the company; and the lines from your panel to your audio system are not also supplying power to noise-producing devices (frig, fluorescents, dimmers, washer/dryer, microwave, A/C, etc) you shouldn't need nuthin' (and please let me know where on the planet one can find those conditions anymore!)

Oh, and have I mentioned all the 21st century wireless airborne digital hash!! That's right!! It can get into even the most pristine of dedicated lines. It ain't just your daddy's radio anymore!
I'll partially agree with Albertporter about conditioners as many just compress the sound.

I have not tried regenerators such as PS Audio so I can't comment on them.

I have used transformers in isolation and balanced setups that have given mixed results from worse to better. As isolation only and properly sized, they have not been any worse. Typically, a small isolation transformer would supply the CDP as backflow protection, in plumbing terms.

If you got noise coming from the speakers when the music stops, isolation might be the simple answer. Unfortunately, the problem may be more complex.
When my system reached a certain level of resolution I noticed that reproduction seemed much more natural and less tense after 5pm, especially during weekdays, and then even more so after say about 11pm or midnight. The involvement factor improved much more so than just implied by ambient noise differences. I added dedicated lines (2 X 20A and 2 X 30A) and still sensed a dramatic (to me) difference due to times of the day. Adding power regenerators rendered the differences of times of listening moot. I'm afforded after midnight purity anytime now. I'm certain that this may be fairly unique to my system due to condo living and which businesses share the power grid I'm assigned to. Also different component's power supplies would have varying suseptabilities to power quality. I feel this would be a good starting test to determine whether you need additional power conditioning or regeneration. As always YMMV.
I have a power conditioner in my system. I've read many pros and cons, primarily sonic considerations about them. I remain neutral as I truly don't hear a major difference in sound quality. Suffice to say, if it made a substantial change for the worse I'd remove it. The biggest benefit for me is that it accepts so many plugs and in essence just cleans up all that spaghetti and power strip nonsense I had going on for so long!;)
A friend of mine has lent me his PS Audio P300 on three seperate occassions and a large balanced power unit one time. I only used these devices for cdp and pre and had them for long auditioning periods. I could never discern a difference using either of these units, either positive or negative. The audio community sometimes makes me feel as if I'm doing myself a disservice by not using some sort of conditioner. But my findings are strengthened when I read posts' such as the one above from Mr. Porter. But, as stated, I'm sure in some situations they are beneficial. I am running two 20amp dedicated circuits...
It's so interesting to read the different experiences people have had. I agree with everyone, but also think it's important to investigate your own particular situation. I used to have a house here in central Tucson. The power grid I was on also serves the U of A and the (huge) U of A Medical Center. The power was always above 122 (usually 123V) and never a hiccup (except occasionally during thunderstorms when it just flat quit!)

So I'd never even thought about power devices. Yes, installing dedicated circuits made a big difference in lowered noise floor and bigger dynamics, and I quit right there (un-intimidated!)

2 years ago, I sold my house and now live in a 50 unit apartment complex ca. 1950. It's on the same grid as my former house. Without even debating the issue, I bought both the ExactPower units and installed them; the balanced unit, for the source stuff, is powered by the main regenerator unit. It was all fed by some nasty 15A branch circuit. It did sound great though, and I settled down to a life of processed power ;~((

Then, one day when labeling the (real fuses) in the fusebox, I ran across a 20A circuit that I couldn't trace to anything. With my adrenalin pumping, and a few mis-steps (read: electrical shocks) later, I discovered it went (ONLY) to an outlet under the kitchen sink, meant for a garbage disposer that was never installed! OH JOY!! ;~))

I bypassed the disposer wall switch, with soldered connections. Changed the wall outlet for audiophile grade. Cleaned and Caig'ed the fuse and socket. Then I made a 12 foot Belden 10AWG umbilical to the ExactPower regenerator and let 'er rip!

Result: Sounds as good as it ever did at my house (Note: my whole system only draws 450 watts at full bore)

Moral: Always label your fuse or breaker panel!

To elaborate on my experience I was getting very good results with a Chang Lightspeed device, and I was surprised when I took it out and inserted a simple Wiremold power strip the sound actually improved. High's seemed more extended and the sound was more lively. Thus as I and others have said, experimentation is key.
Thank you all, that helps a lot. I understand now that people's situations vary and that sometimes a power conditioner may improve things and sometimes not, and that experimentation is key. Also everyone agrees that dedicated lines are the way to go.

So that leads me to another question. Although I would love to have a dedicated line for each piece of gear a la Albertporter, (FOURTEEN!!!) that isn't feasible right now. At the moment I've got only one with a dual outlet on it. I am in a private home, so let's assume for now (until I have time to experiment with a conditioner) that the power is sufficiently clean and not in need of a conditioner. What is the best way to use this one outlet? E.g. all the stereo gear branched off of that via a power strip? Or say just the one component that is most in need of clean power (amplifier perhaps?) so that it's isolated from the other components? (leaving the rest of the gear to "dirty" outlets).
Sometimes you don't know until you try.
Well for the past 2 years I thought twisted dedicated lines seperate breakers on a dedicated ground were more than enough..

Enter: Equi=tech Balanced Power. Equi=tech runs gear for large sound studios, broadcast facilities etc, and home owners.

I purchased the Plane Jane Balanced Power Transformer in a box, and ran the output line to secondary breaker box where my dedicated lines connect. This is the simplist product that they sell.

The change was immediate and undeniable, but after 3 weeks. The overall change is overwhelming. TV / Satelite / Sourround system. Music how has sparkling clarity, . CD, DVD's especially a really large improvement. The picture is sharper and crisper colours are more saturated. The bass is HUGE it has grown, expanded, got deeper, tighter, more expressive, and unbeliveably powerful. Where is this bass comming from ????? The upgrade was worth it just for the Bass improvement.

My 2 channel using Klipschorns set amps, and Vinyl.. I could describe it as more immediate with pristine crystline clarity , more low level information, huge bass improvement.. better still, the music creeps out and grabs you, sucks you into it's captivating and enthralling musical vortex: and 20 minutes later you are released from its grip yet again to flipp the dam record!!! Enjoyment level 2-300% improvement.

I would like to try their other products.. A new line conditioner just for large plasma, and Hd TV rigs.. humm...

Yah I am convinced. Hydro is dirty, Balanced Power seems to lower the floor noise, and improve the bandwidth while injecting sparkle and pizazz. oh and did I mention bass
Anolog - What Equi-tech model are you using? I have the Son of Q and am very happy with it. It's almost the bottom of their line, and I'm pleased...
I have the Q type Transformer in a box. This was listed in the clearance bin at $399. You get the q -transformer with no extra power conditioning or filtering, no ac regulation and no outlets. You have to wire the transformer into the hydro box.. and then the line out from the transformer goes secondary breaker box - (8 breakers) where you run your dedicated lines. This worked for me.. I have 4 lines with schurter connectors on the ends so they plug directly into my amps / preamps ets. (no power cables needed) I also twisted my ac lines, which helps to cancel rf, and magnetic interference.
Can you provide a website for the product you mention?
- products - used equipment and factory blems.