I've recently decided to be open-minded (for a change, so I'm now into cheap-ass tweaks. A friend managed to talk me into this story how, due to certain piezo-electrical properties, some crystals can affect low voltage circuitry, blah blah blah. To cut the long story short, I took some of the crystals that my wife has lying around in her studio (rose quartz and amethyst, mostly), and installed them on the AC power cables and interconnects, etc.
Listening impressions: weird. It's not that I could hear any new, previously unheard details, it's just that the well known details in well known songs appear to contain more depth. Not depth in the sense of deeper soundstage, but depth in the sense of deeper sound, sound with more sparkle and presence. In general, more enjoyable sound quality.
I'm sure it's nothing but a very strong placebo verging on self-hypnosis, but I'm still curious if anyone else had ever experienced something similar. Also, I must insist here that I'm not all that prone to placebos, as I've demonstrated, on more than one occasion, that glitzy, ultra-expensive hi fi gear can leave me totally cold. What I'm trying to say is that I'm not easily falling for good looks when it comes to hi fi gear... That is, until now.