How do you know if you need a power conditioner?

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.