I've been using a JC-3 for over a year and can say it is one of the most neutral phono stages out there. When I say "neutral" I mean that it does not editorialize the signal, it will pass what ever is delivered and will respond to tweaks and power upgrades.
If the TT/setup is perfunctory it will reveal it and also if it is superlative, it will reveal it as well. The JC-3 will also reveal the power integrity fed to it and as such is a true high end phono stage, IMHO.
It is true that the input flexibility is limited and that was a concern when I bought it but it has proven to be a non issue for me so far.
Feed it clean power, preferably balanced or even better AC regeneration and pay attention to what it is sitting on and you will be rewarded. I have mine on a SR Tranquility Base being fed by high current balanced power via a SR Hologram A power cord and the results are sonic bliss!
John Curl is considered by many to be the guru for small signal amplification as this is clearly the case with the JC-3, in fact many consider the JC-3 a descendant of the famed Vendetta phono stage but on a budget.
Bottom line is feed it clean stable power and pay attention to what it's mounted on and you will be most rewarded :-)
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