power conditioner

are you in the US?

apparently some countries have really dirty power - the Australians seem obsessed with that issue for some reason

blind listening tests are critical to evaluation and I bet you find that better speakers and room treatments are much more important...

randy-11

... blind listening tests are critical to evaluation ...

Perhaps that's true for you, but most audiophiles have no use for blind listening tests. They're tricky to conduct properly and if they're not done properly, the results are of no value. They're also time-consuming, and that time takes away from listening just for fun.

Double-blind tests do have value for designers and manufacturers, no doubt. But for hobbyists ... not so much.

Consumer audio is rife with confirmation bias.  The only way to eliminate that problem is to use blind tests.  While true that it is troublesome, it can save thousands of dollars.

randy-11

Consumer audio is rife with confirmation bias.  The only way to eliminate that problem is to use blind tests.

You've committed the logical fallacy of the excluded middle. Long-term listening will reveal a component's true qualities, and without all the time-consuming, fiddly nuisance and level-matching  of blind testing.

I use a power regenerator. All my gear is plugged into the Regenerator. Major inprovement in sound. Filters never did anything for me. Also blind testing for audiophiles is worthless. Live with a component for a couple of months playing a lot of music and you will then be able to tell if it is for you.
Blind or doubleblind testing is designed to tell if there is a difference in sound, not which is better. Did you know in a blind test if you listen to A and then to B most people will prefer B
Alan