Pioneer PT-R7III
¥ 48,000 (released in 1982)
Commentary
Beryllium ribbon tweeter developed by improving ribbon tweeter PT-R7A.
The entire surface of the diaphragm is in the same phase and receives the driving force more uniformly.
Since the vibrating part itself is the driving part, an extremely light vibration system can be constructed without waste, and the diaphragm is easy to move and achieves excellent linearity.
Beryllium, which is the lightest and most rigid material of the diaphragm for the ribbon, has been adopted to realize high efficiency and high input resistance.
In addition, the ribbon is formed into a regular hexagonal pyramid pattern by a unique manufacturing method. Since the cut surface does not form a straight line in either the vertical, horizontal, or diagonal direction, it has a strong structure that does not worry about bending. In addition, a large compliance edge is provided at the end of the rigid part of the ribbon, and it is sandwiched by silicon elastic body to realize accurate piston motion.
The magnet uses Alnico 750.
The magnetic flux density of 7,400G. ensures uniform magnetic flux distribution and greatly improves transient characteristics.
A low-inductance power supply system has been adopted that greatly reduces the inductance up to the ultra-high frequency range.
This reduces the generation of slight inductance in the feed section and improves the energy characteristics in the high frequency range.
A matching transformer with a wide-band, low-loss design using multi-layer sandwiched winding of oxygen-free copper foils is adopted.
High resolution has been achieved by adopting a permalloy core with linear initial permeability characteristics.
The terminal is gold-plated.
In pursuit of sound quality, it uses a protective circuit with a fuse in the oxygen-free copper cap.
Comes with a stand base that can be set directly on the cabinet.
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Model Rating
| Type | Ribbon tweeter |
| Input impedance | 8 Ω |
| Playback frequency band | 5 kHz to 120 kHz |
| Max Input | 100W (5 kHz, when using -12dB/oct network) |
| Rated output | 50W (5 kHz, when using -12dB/oct network) |
| Output sound pressure level | 97.5dB/W/m |
| Crossover frequency | 5 kHz or more at -12dB/oct. |
| Total flux | 180,000Maxwell |
| Air gap magnetic flux density | 7,400Gauss |
| Protection circuit | Fuse type |
| External dimensions | Width 134x Height 89x Depth 179 mm |
| Weight | 2.6kg |
| Attachment | Stand base |