yes, using a quality neutral distributor to compare is the best way like what Watchdog has done. and I base my buying on their recent evaluation here and decide which receptacles sound characteristic I like.
https://hificafe.sg/forum/index.php?topic=260.0 Anyway after further listen session on the receptacles , this is my take on the receptacles:
SINE , SW-2LP US(Platinum )Vocal is nice as it place the singer more forward and you can pinpoint the vocal image very clearly, this mid range vocal is essential to music. The high frequency range is nice for jazz music enjoy as you can hear all the high frequency details, but if you system is already on the bright side, then this receptacles may not be suitable as it will give too much treble. Bass control is the weak link here as not as tightly control. Sound stage depth and width is quite ok. receptacles come with the aluminum face plate so is cost saving here.
Furutech GTX-D NCF Vocal image is place further behind so it gives more image depth perception. Bass control is good as tightly control the bass woofer. High frequency details is very well present and is very sweet sounding, will not get listening fatigue. Bad is very expensive here and best to buy it from amazon Japan, also does not match with SINE aluminum face plate, end up I need to buy another face plate to match it.
I will change to the Oyaide R1 later to compare and will update back on this thread in future.