Least Expensive Power Conditioner/Surge Protector That Won't Worsen Sound

My question is whether some units/designs might actually worsen the sound from source equipment. Theoretically, reducing noise in the electricity would improve blackness of background, exposing finer detail, as well as improve dynamics. Might it also color (or discolor) the sound in some way, i.e., brighten, gray, dull, or flatten the 3-dimensionality of the sound?

Again, I'm just asking about source equipment, including phono preamplifiers.

@analogj , your question has merit. I've tried a couple passive conditioners for my sources that coloured the sound: eg, added warmth instead of remaining neutral, restricted dynamics, removed that sense of "air" and sense of space. They lowered the noise-floor, but at too great a cost.

These were name-brand products, but used too much filtering which affected sonics. I found many more conditioners at the same price-point which used different technology to achieve better results. I now use balanced power for the majority of my sources and a Brick Wall for a couple digital devices.

@buddyboy1, oh god yes, I immediately noticed an improvement in sound quality when I got on board the Garth Powell from AudioQuest’s clean power train. Powell designs all of the power conditioners and higher end power cables at AudioQuest. I noticed a much crisper and more clear sound from my system, with a much blacker sonic floor and greater detail and instrument separation in the music that I listen to. I use an AudioQuest Thunder power cable to go from the Niagara to the wall socket. Honestly if I had more money I would’ve spent at least twice as much on the power cable and conditioner because I feel that they quantitatively improved the SQ in my setup by at least 20%. 

@adasdad How was the PQ2, and what was the SQ leap from that to the Niagara? Both are designed by Garth, right? I've read mixed things thus far about the PQ2 and PQ3 in terms of sound.  

@analogj, the PowerQuest2 to my understanding was not designed by Garth Powell. For me it acted as a really good surge protector with some adequate noise filtering that made it a much better choice for an audio or home entertainment system than your average hardware store power strips. There really is no comparing it to the AQ Niagara series of power conditioners because the Niagara’s are audiophile grade units for dedicated hifi systems. The price of the PQ2 makes it a good place to start as you build your system or if you just want to have piece of mind protecting your audio gear. 

I took erik_squires advice earlier this year and got a Furman unit with LiFT and SMP. No degradation of sound, in fact the sound improved.