How do you know if you need a power conditioner?

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...