Utterly failed my Law of Efficacy; a real waste of time tweak. About once a year or so I try such a tweak to revisit my standards of improvement of a system. And as would be suspected, this seeming wondrous trick failed miserably.
I tried not just the expensive copper unions, but also galvanized couplings;, and frankly, if anything I felt the galvanized coupling at 1/4 the price was better.
But, both seemed to have not an efficacious, bur rather a deleterious effect, though very slight. To me the effect was more like a power filtration device, which would hurt the micro dynamics, not improve the sound overall, imo. It reminded me of why I eschew power and cable filters, because to my ear they kill the extreme nuances of the performance.
My judgment: A waste of time as it brings no fantastic change to the rig - far beneath my criteria for an efficacious change - and if anything, kills a degree or two of micro dynamics. I would not recommend this tweak to anyone, as one's money is far better spent being put toward a component or cable.
To contrast this experience, after I did the coupling/union test I swapped one power cord, on my Wells Audio Innamorata Amp (reviewed for Dagogo.com). The effect was profound in comparison, immediately noticeable across the board from tone to dynamics to detail. No "critical" listening, i.e. straining to tell the difference, was necessary, but it was obvious, the exact opposite of the copper sleeve test. The cable change was efficacious, the sleeve not.
Imo tweaks like this will soon bring the audiophile to frustration, as they will be limiting their rig with insipid changes, thinking they really have it right when they are far from a superior sound, which could be had by making serious changes. :(
