Audio Database DENON DL-305 65,000yen(around the 1980 time) Description �@ It is MC type cartridge which adopted the amorphous boron pipe. The new-materials amorphous boron pipe with a wall thickness of 0.025mm is adopted as a boom. the ratio which was excellent though the boron was light -- while having rigidity (Young's modulus/density), it has the physical properties of the fusing point of 2,300 degrees C, and has become the element optimal as a material of a boom. And since an amorphous boron is in the amorphous state with which small particles were tightly got blocked, compared with the crystal boron which is a collection of big crystals, destructive intensity is large also about three to 4 times. In order to use this material in the optimal state, while succeeding in the ultra-thin pipe formation by the original C.V.D. (Chemical Vapor Deposition: vapor phase epitaxy) method, it is realized [ of the boron emulsion side / equalization and ] whether it is precise. By this, the weight saving of the effective mass of a vibration system is carried out to 0.168mg, the mechanical impedance in upper register is held down to the minimum, and faithful and exact trace is enabled with light needle pressure. The solid diagram special ellipse needle is adopted as a needle, and 0.01mg or less is realized. The taper cut of the point of the boron pipe which fixes a needle is carried out, and it is correctly attached to the precise rectangle hole by laser beam processing. The power generation coil maintained the optimal mass balance while making the whole vibration system light using the cross type volume frame of hard resin, and it has eliminated the slump of the characteristic by division vibration. This volume frame system has a merit which it is possible to wind a coil around a vibration-system axis symmetrically, and can arrange many characteristics of a right-and-left channel. In order to obtain a small and powerful magnetic field, a rare earth cobalt magnet and a rational yoke structure are adopted as an internal structure. Moreover, a vibration system is supporting with the one-point type of mounting which has a track record in DL-303 and DL-103 series, can always hold a coil correctly in the center of a magnetic field, and is suppressing distorted generating by a power generation system low. Rating of a mode Form MC type cartridge Output voltage 0.2mV (1kHz is horizontal 5 cm/s) Play frequency range 20Hz - 75kHz Output load impedance 40ohms (20Hz - 20kHz) Conformity load 100ohms or more (about [ transformer ] 40 ohm) Channel separation 28dB or more (1kHz) Channel balance Less than (1kHz) 1dB Static compliance 35x10 to 6 cm/dyne Dynamic compliance 14x10 to 6 cm/dyne (100Hz, record measurement) Needle point (chip) 0.05x0.1mm angle solid diagram special ellipse needle Proper needle pressure 1.2�}0.2g Tare 5.8g Needle exchange Main part exchange (\39,000)