Audio Technica AT-OC9/III

Shibata stylus moving coil cartridge

The AT33sa cartridge is Audio-Technica’s first moving coil model equipped with a Shibata diamond stylus. In addition to improved high-frequency performance, thanks to an ideal contact surface, the Shibata stylus delivers solid, richly detailed bass and midrange. The Shibata stylus is mounted on a boron cantilever with a double damper, considerably improving sound quality.

Advanced tapered boron cantilever, reduced mass

The AT33sa cartridge uses a tapered boron cantilever. This tapered shape and the revised coil winding reduce mass, giving the cartridge better high-frequency performance and more balanced reproduction.

Neodymium magnet, increased magnetic energy, and permendur structure

This model uses a neodymium magnet with a maximum energy product (BHmax) of 50 [kJ/m3]; its structure is made of permendur, a material with high saturation flux density and exceptional magnetic properties, further enhancing the concentration of the magnetic field on the coils.

PCOCC wire moving coils

The PCOCC wire coils ensure purer audio signal transmission, as the signal is not subjected to granularity effects in the electron emission direction. PCOCC = Pure Copper by Ohno Continuous Casting process (high-purity, oxygen-free monocrystalline copper)

Dual moving coil, high channel separation, extended frequency response

The basic structure is that of a typical moving coil cartridge, with separate cylindrical coils for the left and right channels. Since the output voltage is generated independently on each channel, this design ensures exceptional left/right separation. Otherwise, if the signal from one channel leaks into the other, intermodulation distortion occurs, significantly degrading audio quality and stereo image width. This product’s structure ensures a clear and smooth sound. Moreover, the two coils have an inverted V arrangement, effectively reducing the effective moving mass “seen” by the stylus. This design limits superfluous coil movements, further reducing distortion.

VC mold limiting extraneous vibrations

The VC mold holding the coils in place is made of a hard synthetic resin mixed with potassium titanate to further enhance its rigidity. This improvement results in greater lightness, further reducing extraneous vibrations.

A solid body with a rigidity-focused design

The cartridge body is made of a precisely molded hard aluminum alloy. A very hard synthetic resin is used in a sandwich structure for the top and bottom of the body to suppress parasitic resonances. This reduces unwanted noise while improving rigidity and the S/N ratio.

Dual Moving Coil Cartridge

• Special Line Contact stylus
• Based on the design of the highly acclaimed AT-OC9ML/II
• VC mold reduces extraneous vibrations
• Dual moving coil provides high channel separation
• PCOCC coils and terminal pins
• Solid body, increased rigidity

Measurements

• Frequency Response: 15 - 50,000 Hz
• Body Material: Aluminum
• Channel Separation: 30 dB (at 1 kHz)
• Channel Balance: 0.5 dB (at 1 kHz)
• Output Voltage: 0.4 mV (at 1 kHz, 5 cm/sec)
• Vertical Tracking Angle: 23°
• Vertical Tracking Force: 1.8 to 2.2 g (standard 2g)
• Stylus Type: Line Contact (curvature radius: 40 × 7µm)
• Stylus Curvature Radius: 40 x 7µm
• Stylus Mounting: Solid diamond, square shank
• Cantilever: Solid boron, Ø 0.26 mm
• Coil Impedance: 12Ω (at 1 kHz)
• Coil Inductance: 25 µm (at 1 kHz)
• DC Resistance: 12Ω
• Static Compliance: 35 × 10 - 6 cm/dyne
• Dynamic Compliance: 18 × 10 - 6 cm/dyne (100 Hz)
• Recommended Load Impedance: ≥ 100Ω

General

• Dimensions (W x H x D): 17.3 x 16.8 x 25.7 mm
• Cartridge Weight: 8 g
• Included Accessories:
  • Non-magnetic screwdriver
  • Anti-static stylus brush
  • 2 washers
  • 2 nuts
  • 2 mounting screws 11 mm
  • 2 mounting screws 16 mm
  • 1 plastic protector
  • 1 set of PCOCC lead wires (AT6101)