Kiseki Black Heart NS MC Phono Cartridge

Made in Japan.
I kept it as a backup (I used it for about 50 hrs) but since already have two other carts I decided someone could enjoy this one (especially since it is getting harder and harder to get it- the wait time is about 8 months). 
The sound it produces is absolutely amazing. It is a bit more detailed and dynamic compared to the iconic Red Heart. 

The Kiseki Black Heart NS model was first introduced in the ’80s. Now, as then, the body of the new Kiseki Black Heart NS is machined out of solid Black Heartwood, but now has a smaller size (short body or "New Style"), like the Kiseki Blue N.S.

The motor is based on the same parts Kiseki is using for the other current Kiseki N.S. models.

The BlackHeart N.S. is the first model to use a solid nude diamond mounted both in and through the boron cantilever, instead of just mounting it on the cantilever. This results in a mechanically better construction for better signal reproduction as well as higher reliability.

SPECIFICATIONS

• Body: BlackHeart Wood, 25 mm long
• Cantilever: Solid Boron Rod: 0.28 mm diameter
• Stylus: 0.08 x 0.14 mirror polished diamond
• Stylus tip radius: 3 x 30 μm
• Stylus mount: In cantilever
• Vertical Tracking Angle (VTA): 20 degrees
• Coilbody: pure iron
• Weight: 6.4 grams
• Output voltage: 0.48mV at 5cm/s
• Internal impedance: 40 ohm
• Frequency response: 20 – 30.000Hz ± 1dB
• Channel balance: 0.2dB
• Channel Separation: 35dB at 1kHz
• Tracking ability at 315Hz at a tracking force of 2.6 grams: 80 μm
• Dynamic Compliance: 16 μm/mN
• Recommended loading: 400 ohms 
• Recommend tracking force: 2.0 – 2.6 grams 
• Optimum tracking force: 2.4
• Recommended tone arm mass: Medium
• Optimum working temperature: 20 °C
• Break-in period: 50 – 100 hours