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

@edgewear

By now I’ve seen pics of several slightly different pre-Platinum Onyx short bodies; it’s almost impossible to say exactly what you have, unless you get in direct contact with Koetsu. Still so much mystery with Koetsu!

I don’t personally know of any Platinum Koetsu that doesn’t have a leading "P" in its serial number, but that doesn’t mean it can’t exist. There could be pre-Platinum Koetsus that were later rebuilt with Platinum magnets (with original top plate retained).

You might join the "Koetsu Users" Facebook group, which has some interesting vintage Koetsus posted & discussed by members. These groups have the advantage of easy image inlining.

In a revision of my previous comment on this thread, I would now estimate my non-platinum Onyx at between 0.4 and 0.5mV output. Not fully double the Platinum model’s 0.3mV, but still quite noticeably higher. I would guess its magnet is most likely samarium-cobalt or permendur (i.e. like the Black, Rosewood, and Urushi models). The fabled long-bodies should use alnico - very large alnico magnets were necessitated by the (relatively) weak magnetic material, which required the long bodies to house it!

As to sonic matching - I absolutely prefer all my Koetsus with EAR SUT (or Koetsu SUT, or Quadratic MC-1 SUT) over any active MC stage, including that of my ARC Reference 3SE. FR64S and 64fx arms here. But then, every system is different! 

Not sure about how one dates a stone body Koetsu.

Carbon dating?

Platinum magnets are like green eggs and ham.

I do not like green eggs and ham.

I have dated numerous Koetsu's over the years, and the allure has waned with the passing of the old master and the advent of platinum magnets.

I experiment with swapping a lot of gear - depending on partnering gear, the non-Platinum magnets (Onyx in my case) work better in some cases, and Platinum works better in others. The non-Platinum magnets have more output to work with. They're also a bit more brash and dynamic / punchy sounding. The Platinum magnets are smoother and more refined sounding. But OP need not stress over which magnet his Onyx has - just listen and enjoy! The Platinums cost more but are not necessarily better. 

Blue Lace Platinum combines the smooth lushness of Platinum magnets with better dynamics and detail compared to other stones or RSP. It's the best. I also like Onyx Platinum, but it lags a little behind the Blue Lace. The warmer / softer sounding stones like Jade and Coralstone can be just too over-smoothed for many systems. 

Hi@statman71

I certainly hope you received a satisfactory response to a question you posted 5 years ago.  I find this of interest.  I only recently joined this website and peruse the forums.  Even though it has been 5 years may I reinforce the comments of others especially the knowledgeable mulling.

It was some years ago that I purchased two Koetsu Onyx Signature cartridges the same day at the same store.  Serial numbers:  #1167 and #1169.  One was purchased as a present (which never happened) and one I mounted on Oracle turntable fitted with a SME V tonearm.  I still have both cartridges, the #1167 is now mounted on an Oracle Delphi Mark VI with a SME V tonearm, and the #1169 still remains in its box and never used.  I presently have three Oracle turntables (I had others that I sold).  What can I say who buy two Koetsu cartridges at a time, and who has/had a collection of Oracle turntables.  But it makes for great comparisons.  Yes I also owned a Koetsu Onyx Platinum.  Operative word being "owned".  I had it for a relatively brief period.  A semi-friend was primarily interested in purchasing one of my Oracle Mark IV tables.  He also liked the Alphason Xenon tonearm I had but was not pleased with the Benz-Micro MC-3 Gold that was mounted, but wanted a Koetsu.  I was not going to part with the original Onyx Signatures because I considered the non-platinum cartridge very much superior to the Onyx Platinum.  So, I parted with the Onyx Platinum for that reason.

I do not know the reasoning, but the non-platinum, In my opinion, is superior.  Whether it is because it was fabricated by the Master himself, Yoshiaki Sugano, or because of the output voltage of 0.44mV, or because of its weight at 14.95 grams - I have no idea.  I realize that after Sugano San was fading from the operation the idea to incorporate platinum magnets to control the eddy currents was the reason that I found the Onyx Platinum inferior, or, was it that Yoshiaki Sugano was no longer involved personally in the fabrication or finalization.  I do not know.  It was shortly afterwards that the company went almost dormant for 3 to 4 years.  And Platinum was promoted as superior when the manufacturing was resurrected.

Nevertheless,  I had the opportunity to listen to both on identical Tonearm/Turntable and Phono Pre-amp set-ups, and easily be able to switch among speakers.  To me there was no question, tho non-platinum Onyx cartridge is superior.  To this day this one arrangement exists and gives me great pleasure.  The suspension system (surprisingly) is still working well, considering the Keotsu cartridges are not good tracking cartridges.  When new, they both, that is, the Platinum and the Non-Platinum just passed my "Test" record at 70mu.  At times even 65, but they improved a bit over some time.

I realize that this is no more than further verification of what others have stated.  And, as a new member, I just wanted to insert my two cents worth of opinion.  I realize that the word "Platinum" is a great Marketing tool, but, I think the Koetsu Brand could "Actually" (Hard to comprehend) even improve their products if they reverted back to the Samarium-Cobalt or other magnet materials, and, forget the Marketing, because they already HAVE the reputation.  They do not need any gimmick.  But, that is my humble opinion as someone who has a M.B.A. in Marketing as well as a Doctorate in Chemistry.  Sorry - A bit much.  My apologies to Koetsu.