Koetsu Coralstone
- Thread starter rockitman
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Christian, the question that was raised in this conversation was that no one has actually ever seen an image that documents that the diamond cantilever and stylus are one and the same. But if true, this person felt it was a tremendous advantage.
It depends. When running my SS Pass XP-25, I Liked 250 or 320ohms. If I run my nuvistor tube headlamp...Allnic HA3000 into the mm inputs(47k) on the Allnic H5000 DHT, I run either 100 or 200 ohms. If I go direct coupled transformer input on the H5000, I have no Idea as there is no loading control. You just select your gain/turnover.
Christian, that does not look like it was cut from the same piece of diamond. Looks like they laser cut a slot for the stylus to fit in. This would require less glue and be more precise, in holding the stylus in the correct plane. When styli are just glued on, I always wonder how square it is to the cantilever. If it's not perfectly square then the zenith would be off.
I just read how to calculate loading when going through a SUT, the other day. It's not that difficult. First you need to know the MM input loading which is 47,000 ohms on most phono stages. Then you need to know the amount of turns your SUT has. Since your SUT has 4 different turns ratios the loading will depend on which setting it's on. So once you have this info you can calculate the loading for each setting. First you divide the MM loading 47k by the turns ratio for example 40/1. Which will be 1175. Then divide that number by the turns ratio again and you get 29.375 ohms. So you basically you divide the MM input by the turns ratio squared. So if your H5000 has the same turns ratio's as my H3000, then the loading will be as follows. The +22 db setting is 13/1 turns ratio and therefor the loading is 278 ohms. The next setting up is +26 db, and has a 20/1 turns ratio, so the loading is 117.5 ohms. Next setting is +28 db, and has a 26/1 turns ratio, loading is 69.5 ohms. Then the highest setting is +32 db with a 40/1 turns ratio, loading is 29.3 ohms.
Not sure why they can't put that in the manual, but at least we know how to figure it out now.
It's hard to tell. The dark area at the end may be the reflection of the cart body. It would be nice to have one...
Good info. Thanks for that. Those are the same ratio's the H5000. Based on that, I am running my Coralstone at 69 ohms via the transformer input.
Do you mean, like an Excel spreadsheet? I'm sure it can be done, but I do not know how to do that personally. It would be a good skill to have. Maybe someone else on the forum, knows how to put that together?
This is the website I got the loading calculations from. http://www.rothwellaudioproducts.co.uk/html/mc_step-up_transformers_explai.html
I haven't run trans input much lately, but tonight I prefer 32dB gain or 29.3 ohms on the Coralstone.
If you look at the specs of the KCP from needle doctor, I think the recommended loading is 30 ohms.
Internal impedance. Somehow that doesn't translate with active (non transformer) based gain stages. When I went down to 50 ohms on my Pass XP-25, it didn't sound very good... way over damped. Passive transformer loading seems to be different from active gain loading in my experience.
I have seen and sold 4 units of Koetsus with the Diamond cantilever option, and from my own examination, I did take a very close look at the cantilevers/stylus assembly, as I was very curious based of my regional dealer's claim that it is cut from one piece and not joined, I have to say that they looked like they were cut from one piece. Plus the damaged diamond cantilever that I mentioned earlier here, it looked like that the stylus snapped off the edge of the cantilever and I did not see a hole in the cantilever where the stylus was snapped in and glued or anything like that. Too bad I did not take macro shots of it then, just regular close in shots, but my pictures do not give a seamless connection of the stylus and cantilever from afar, quite different from my own naked eye examination.
I lust for the diamond. I would be scared dragging it through a stylus brush. I wonder what you gain is sound quality with the same stone but diamond versus boron cantilever ?
And here is the mention of the Diamond option machined from a solid piece of diamond. The guy was my regional dealer then. And if there is one guy outside Sugano and his inner circle that knows Koetsu, it should be him.
http://www.koetsusea.com/Why-Rebuild-a-Koetsu-.php
Why Rebuild a Koetsu?
1) Koetsu does not retip their phono cartridges.
2) Koetsu REBUILDS their cartridges.
When a Koetsu is sent for rebuilding, all the elements in the cartridge are replaced - only the cartridge body is retained. This might be seen as wasteful but there is a strong reason for it.
A phono cartridge's performance does not merely depend on the condition of the cantilever or stylus. A cartridge with a brand new stylus is not going to do the music any good if the suspension is weak or if the coils are oxidised. This is akin to replacing the engine oil in your car while retaining the old spark plugs and oil filter. The car will still work, but it's performance will be terribly off-spec and suboptimal.
Replacing all the elements in your Koetsu phono cartridge will give it a new lease of life. It will be equivalent to getting a brand new cartridge. In fact, as the Rosewood body ages, it will add considerable value to the sound (which is why the Rosewood Signature Platinum [aka Pro IV] uses Rosewood which has been allowed to age naturally).
(TIP: Want a great sounding Koetsu at a lower cost? Get an old Rosewood Standard or Signature and have it rebuilt!)
Rebuilding your cartridge ensures that it will perform at the level which you've come to expect from your Koetsu cartridge.
For the more demanding Koetsu owner, Koetsu Japan is able to rebuild higher spec innards into their current cartridges. For example, upgrading the existing cores with the Platinum-alloy set.
Another upgrade is the Diamond cantilever option. As the name suggests, the stylus/cantilever assembly is machined out of a solid piece of diamond. This 'monocoque' structure effectively removes the interface issues associated with regular stylus/cantilever assemblies.
This is how Koetsu preserves your investment...
http://www.koetsusea.com/Why-Rebuild-a-Koetsu-.php
Why Rebuild a Koetsu?
1) Koetsu does not retip their phono cartridges.
2) Koetsu REBUILDS their cartridges.
When a Koetsu is sent for rebuilding, all the elements in the cartridge are replaced - only the cartridge body is retained. This might be seen as wasteful but there is a strong reason for it.
A phono cartridge's performance does not merely depend on the condition of the cantilever or stylus. A cartridge with a brand new stylus is not going to do the music any good if the suspension is weak or if the coils are oxidised. This is akin to replacing the engine oil in your car while retaining the old spark plugs and oil filter. The car will still work, but it's performance will be terribly off-spec and suboptimal.
Replacing all the elements in your Koetsu phono cartridge will give it a new lease of life. It will be equivalent to getting a brand new cartridge. In fact, as the Rosewood body ages, it will add considerable value to the sound (which is why the Rosewood Signature Platinum [aka Pro IV] uses Rosewood which has been allowed to age naturally).
(TIP: Want a great sounding Koetsu at a lower cost? Get an old Rosewood Standard or Signature and have it rebuilt!)
Rebuilding your cartridge ensures that it will perform at the level which you've come to expect from your Koetsu cartridge.
For the more demanding Koetsu owner, Koetsu Japan is able to rebuild higher spec innards into their current cartridges. For example, upgrading the existing cores with the Platinum-alloy set.
Another upgrade is the Diamond cantilever option. As the name suggests, the stylus/cantilever assembly is machined out of a solid piece of diamond. This 'monocoque' structure effectively removes the interface issues associated with regular stylus/cantilever assemblies.
This is how Koetsu preserves your investment...
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