JEWEL TONE MP-20J/MP-20HJ
MP-20J : ¥ 19,000 (around 1979)
MP-20HJ : ¥ 21,000 (around 1980)
Commentary
An MP cartridge with a low-mass design vibration system and a boron cantilever.
The MP-20J is a cartridge unit model, and the MP-20HJ is a head shell attached model.
The chip mass has been reduced to 1/3 of the conventional size.
Uses samarium-cobalt magnet.
Uses Super Permalloy shield case.
0.2tx0.1tMm laminated yoke has been adopted.
Carbon ABS cylinder is adopted.
Uses glass-reinforced polyphenylene sulfide resin (PPS) frame.
The terminal pins are gold-plated.
Magnesium alloy is used for the head shell, and copper Litz wire of 99.99% purity is used for the wiring part.
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Model Rating
| Type | MP Cartridge |
| Format | MP (Moving Permalloy) Type |
| Playback frequency range | 20 Hz to 23 kHz |
| Channel separation | 25dB(1kHz) |
| Output voltage | 4.0 mv (1 kHz, 50mm/sec) |
| Output balance | 1.5dB(1kHz) |
| Load resistance / load capacity | 47k Ω / 100 pF |
| Dynamic Compliance | 9x10-6cm/dyne |
| Static Compliance | 21x10-6cm/dyne |
| Internal impedance | 4,300 Ω (1 kHz) |
| Cantilever | Boron |
| Needle tip | Triangular Tip Diamond 0.4x0.7 mil Elliptical Needle |
| Needle pressure range | 1.3 to 1.8 gr (appropriate 1.5 gr) |
| Exchange needle | JN-P20(¥6,500) |
| Weight | 7.9gr |
| Head shell | Magnesium head shell |