Buzzing noise.

I don’t why when I turn on the power amp first then I hear the buzzing noise from speakers it was not loud but you can hear if your ears very closed next to speakers then I turn on the preamp next, the noise go away but you still can hear the buzzing just very little.!!!!.

A power amp should always be the last component to be turned on, and the first component to be turned off. It is not surprising that there is noise when the power amp is on but is connected to an unpowered preamp.

From your description it sounds like the noise level when everything is turned on is so slight that it might not be a problem at all, and might even be normal for the particular combination of components. But if not it could be caused by a lot of things. Including the possibilities the others have cited, as well as radiated interference between components or cables or the power conditioner simply resulting from them being too close together.

If you feel that the noise level that is present when everything is turned on is not normal, and if the power conditioner is located close to any of the other components, that is what I would focus on first. Either move the conditioner further away, or for experimental purposes try disconnecting it from the system and the AC altogether.

And if the power amp is located close to any of the other components, also try relocating it further away.

And regarding the possibility of a ground loop issue, for experimental purposes try temporarily putting a cheater plug (a 3-prong to 2-prong adapter, with the safety ground pin unconnected) on the AC plug of the preamp.

Let us know the results. Regards,
-- Al

Power amp must be turned on last. My power strip has 2 delayed outlets that I connect poweramp to. 
slight buzz not audible from distance is acceptable and less-likely you'll be able to do anything. 
i would try to use stock power cords instead of aftermarket and see if the noise level is lower and if it is, than i'd return aftermarket cords and either look for replacement ones or stop looking and enjoy the music.

It is normal for a buzz to result if the amp is on and connected to a preamp which is off.

The preamp of course should be turned on first, this to avoid damaging the loudspeakers should there be a turn-on thump.

If the buzz is then so quiet as to only be audible when your ear is pressed to the drivers of the loudspeaker, it simply is not a problem!

Jea48, Almarg and others... can you please advise about the power up/down sequence in my particular case? Frankly I haven't given much thought to which component to turn on or off first, etc. My integrated (Musical Fidelity M6si) has a power standby mode and my speakers (Golden Ear Triton One) have their own amp and is of course connected to A/C. I keep both the amp and speakers on separate power strips and the strips have their own power on/off switch. When powering the speakers off I wait until their internal amp goes into standby and then power down via power strip. In the case of the amp I've been powering it down with its own power switch and then powering down at its power strip. Point here is I haven't been paying attention to the M6Si in relation to the speakers, but based on what I'm reading herein it would still be advisable when powering down to go Amp first then speakers and vice-versa on the power up. But does this really "matter" in my case?