Hey Electricians - Please help

First I would like to admit I am very weak in understanding the terminology or the science of electricity, but I am learning some things, so let's just leave it at that.

My question is this. My current system is hooked up to a Richard Gray's Power Company RGPC 400Pro. I am also using a PS Audio Humbuster to kill the DC noise in my lines (this caused torroidal hum in my amp). Everything in my system is dead quiet, so I am very pleased. However, when I turn the overhead light on and off I can hear a click through my speakers when everything is turned on. The light is a florescent light, btw. I know that the light and the consent that my gear is running through are on separate circuits, because I recently upgraded my socket and even after I turned the breaker off for the socket the overhead light remained functional. The click that I mentioned doesn't affect the sound of my system, so long as I do not turn it on or off when listening, but it annoys me just the same. Perhaps if I understand what is going on here I can either do something to fix it or simply resolve not to be annoyed by it anymore.
Please let me know if this is something you understand and can explain it to me.
My suspicion is that the power wiring and distribution have nothing to do with it. The fluorescent lighting is probably generating rfi (radio frequency interference) at turn-on and turn-off, which is radiating through the air into some sensitive circuit point or points in your audio system's electronics.

I suspect that if you were to bring a battery powered portable AM (not FM) radio near the light fixture it would pick up significant noise as well, at those times, despite having no connection to AC power.

The bottom line, IMO: I wouldn't worry about it.

-- Al
The Sun rises in the East and sets in the West. What you stated applies to almost every one.
You might have the ballast in the flourescent light replaced with a modern one.
That may solve your issue.
Flourescent lights use a big ugly lump of a device to stabilise the light. They get old and start making problems. Replace it, (cost is cheap, at any hardware store $20 or less)
They are usually just in the A/c line with wire nuts. easy to replace, (I have done it) but get a friend who is handy with stuff to do it. (No need for an electrician, any person decent with a few tools can swap the ballast)
Even though the breaker that the light's wiring is on, is different from the breaker your system's sockets are on; they may still be on the same phase of your incoming AC. That puts them in the same, "circuit."
As I recall some audio gear and florescent lighting does not mate well. It may cause recordings made on analog decks too become noisy etc. You may want to change your light fixture to another type if it gets on your nerves too badly. At any rate it may be more cost effective and even more attractive then "fixing" your gear. Just a thought, let us know how you make out.
What you are hearing is the "arc" across the switch contacts when it is closed.
Added thought:. Try changing the switch at the wall first.. As a different (new)one may arc less.
For an even cheaper.. just try tightening the wires to the switch, they nmay be loose.
Sounds like a ground issue. Easy no cost check: First, pull the PS Audio out of the circuit and see if the pop persists when turning the light on/off. Next, if the pop is still present, back up to the RGPC 400 and pull it out of the circuit and see if the pop persists. You implied that your amp is not plugged into the PS Audio device but your preamp and front end components are? Are you using BAL interconnects or Single Ended (RCA)? See, if the amp is not plugged into the PS conditioner, there may be a slight difference in the ground potentials between your preamp and amp. That could make your system a bit more susceptible to electrical noise.
I had an older vacuum tube preamp in the late 80s to 2001 that would pick up hum from any dimmer switch in the house. It would be faint, but there. The only cure was to remove all of the dimmer switches. (Just a side antidotal story).
I concur with Mrderrick and Elizabeth. If you have any unshielded interconnects, then wall switch arcs are the likely cause. You might try unhooking each IC and see if the clicking stops. That will tell you which one may be acting as an antenna and picking up the switch arc.
Dimmers and fluorescent lights are not audio friendly. Change the switch. I just changed all the plugs and switches in my house, and you would not believe how bad the contacts were in the house wiring. Some of the wires turned bluish from too much heat (future fire)created by a loose connection. Get a tester for plugs, and evaluate the plugs and see if they were wired correctly in the room. Jallen
There are dimmers just made for fluorescent lights that are very effective. Also, there are electronic ballast especially made to be used with these special fluorescent dimmers. I have both installed in my listening room and they produce no noise or interference with all the tube electronics I have in the room. The lighting is 'cool' especially with natural light fluorescent bulbs.
Elizabeth adds a very good point regarding loose connections.

Many devices are equipped with screw and stab connections.

The stab in connections are notorious for becoming loose over time.

Loose connections arc and arcing creates noise.

The better connection is the wire bent into a Sheppard's hook and placed clockwise around the screw, then closed into an eye and tightened.

The saying in the trade is " Push Or Screw, It's All Up To You".

Unfortunately time is money and most will push.

If you do decide to change out the device, try to find a heavy duty switch.

It will be rated 120/277 volt and either 15 or 20 amp.

There may even be mechanical clamp terminations on the device and that's OK.
Please report back to us your results with the above suggestions. Would be an interesting learning experience for us all.
This is a common problem. All home light switches arc inside them. An inductive load causes a larger spark, in most cases. Some florescent lights are worse yet. I have to change some new Leviton Decora switches (20 amp switches with just lights) with a different brand. These arc so bad everyone is afraid of them, since you could see it (flash) along the edges of it. They probably could put a capacitor inside them to lesson it, but maybe the average person doesn't care, or know the difference.

It does cause some interference through the line (shares the same neutral and secondary in utility transformer), and RF through air. Also, a little spike depending on what it's switching. I think the first wireless radio transmissions were done with a arc or spark jumping across a gap. Even the small power supply for my laptop gives a good visible arc when unplugged, and causes interference on the TV, that's on a separate phase leg. Like Almarg mentioned above, you'll probably pick it up with an AM portable radio.

I guess it's something not worth the worry in most cases. Even less of a problem, on a separate circuit. Living close to a substation like the one in this video that switches the load would probable be more annoying, at least for myself. [http://www.youtube.com/watch?v=IG7PQOQEFmg&feature=related]
Based on the suggestions given I tried a couple of things and concluded that it is most prominent when my amp is set to the phono stage. The theory of the switch arcing seems to be correct because the phono cartridge acts like a mic and amplifies the click. When it is set to CD I do not hear the click.
I would still like to eliminate the click if I can but I won't worry about it now that I know what is causing it.

Thanks to all of you. I really appreciate it!

Get rid of the RG conditioner, it did more harm in my system than good.
Tmsorosk, I am surprised to hear you say the Richard Gray stuff did more harm than good. Can you explain your experience a bit more? In my experience the 400 I have in my system has made a big difference in a positive way.
What are you using now that is better?