Koestu original Onyx Sig pre-platinum cart vs. later/current platinum Sig comparisons

@wizzzard , You could try opening a post on Audiogon. Otherwise, I am not sure how you would attract experienced Koetsu users. Most of us attribute the decline to Sugano San's death. His son took over and the theory is that he is not as talented. I do not think the QC is as good. In short I prefer My Sonic Lab cartridges at least while Matsudaira San is alive. He is the preeminent living Japanese cartridge designer at this time. Only Jonathan Carr and Ortofon are as or more progressive.

Buying an old cartridge is highly problematic. Retipping the cartridge may not return it to it's former glory even if done by Koetsu. In many instance they just give you a new cartridge in exchange for the old one. Cartridges are like wine. Once you drink the bottle they are a memory only. 

This is a case where things have obviously gone downhill. The current Koetsu line can not compare to the earlier cartridges. No Koetsu fan I know of prefers the later cartridges. If you do not have access to an earlier one get a My Sonic Lab Signature Gold. It is a superbly built, very Koetsu sounding like cartridge.