In my case its outlet-->Bada Line conditioner w/ surge suppressor---> Voltage regulator---> Receiver & power amp.
My sources (CDp, DVDp) Video projector (w/ UPS) and audio pre amps are connected
directly to the Line conditioner.
I met hardcore audiophiles who do not use voltage regulators cuz they claim it degrades the sound. But they have a device connected to the wall plug indicating the voltage, if there are bad spikes, they just turn off the system. I saw this device being sold at SGT home theater.
I use my voltage regulator for my receiver & power amp only. But all audio gears go to the line conditioner.
Once, I was almost planning to shelf my surplus CDp (wasnt performing to my expectation) but after a few days w/ my line conditioner, I noticed some extended highs and the music was much better. Even background music tracks during movies would really make meĀ
notice them (I usually ignore em).
A month later, I read The Complete Guide to High End Audio, and it confirms that the extended highs, etc. are caused by the Line conditioner.