Preamp Noise with High-Efficiency Speakers

Wow, so much fight after just one day! George and Charles, we've already known you are big fans of passive pre or source-direct, but at the end of the day, some of us will turn on an active preamp and some will go preamp-less. Who gets more fun out of music/audio is impossible to determine.

I recently found my iFi iUSB Power supply a great tool to charge my cell phone --- faster than my Samsung Note II's own wall-wart power supply. Yes it cost $199 plus shipping thus qualifies the most expensive cell phone charger I ever use. But I had more fun using it to charge my cell phone than to power my USB DAC ---- I was smiling ear to ear watching this little audio gem charging a cell phone (silly, I know). Anything wrong with that? Can you guys find me a passive cell phone charger that works better?

Yingtonggao's problem was too much system gain with his 104db speakers. As the low gain Cary poweramps seems to have now fixed.

The cheapest way I suggested in one of my first posts a removal of gain by either going direct or the use of a passive, mine or anyones, and that colouration may also be reduced, and that Nelson Pass also recommends this. *Below is is quote again*

It was just couple of others here that started the passive vs active debate.

*A Quote from the master Nelson Pass
We’ve got lots of gain in our electronics. More gain than some of us need or want. At least 10 db more.
Think of it this way: If you are running your volume control down around 9 o’clock, you are actually throwing away signal level so that a subsequent gain stage can make it back up.Routinely DIYers opt to make themselves a “passive preamp” - just an input selector and a volume control.
What could be better? Hardly any noise or distortion added by these simple passive parts. No feedback, no worrying about what type of capacitors – just musical perfection.
And yet there are guys out there who don’t care for the result. “It sucks the life out of the music”, is a commonly heard refrain (really - I’m being serious here!). Maybe they are reacting psychologically to the need to turn the volume control up compared to an active preamp.*

Cheers George

Whart,
I understand where you`re coming from and agree.What`s annoying to me is the condescending 'know it all' attitude toward those who`ve reach a different conclusion from what he believes. Well I `ll leave it alone now,enough has been said.
Charles,

I also know where your coming from, and I'm only
condescending to those who deserve it. We’ll just agree to disagree.

Cheers George

This thread has been quiet for some time but has yielded some well sorted out theories.
I stumbled on it with hopes of finding a solution to a hum problem that seems to center around a phono preamp and like others on here, brought to light by some high efficiency speakers.
I've tried a star grounding system, moving power/ICs, etc.
Have dedicated lines and sub panel, a Balanced Power Technologies 3.5 Sig Plus. After I installed the BPT, the edge I was hearing in the presentation took a step back, and yes, the presentation became more natural.
Along with it came the hum, which was previously more subdued.
I will spend some time this weekend chasing down possible sources, not looking forward to this.
Question is: could the Power conditioner's large transformer be reaching 3 feet or so to the phono pre?