A friend built a dedicated room separated from his house, dedicated lines panel grounding rods, Cardas room ratios etc.
His JC1+ monoblocks amplified system had variations in sound at different day times. Night performance was not what we expected either.
After breaking our heads for months he got an APC power system Isolation transformer + UPS and the results are astonishing !!!! In spite of the praised Bybee technology they have, we were really questioning the amplifiers performance. After the power system installation, tremendous improvement on the music presentation, clarity, definition etc. No placebo effect at all. Checked with several audio friends that were trying to solve system issues.