Audio Database

The

Pioneer PT-R7III
48,000yen(1982 release)

Description
 
The beryllium ribbon tweeter which improved ribbon tweeter program transfer-R 7A, and was developed.

It is a whole surface drive system which the whole diaphragm surface is the same phase, and also receives driving force uniformly.
Since the vibration portion itself is an actuator, very light vibration system without futility can be constituted, and the linearity which was easy to move a diaphragm and was excellent has been realized.

As a diaphragm material for ribbons, it is the lightest-weight, moreover the beryllium of a high rigidity is adopted, and a high efficiency and input-proof -ization are realized.
Furthermore, since the ribbon is fabricated by the original process to the pattern of right 6-sided pyramids and it does not become a linear line at all about a cutting plane in length, width, slant, and which orientation, it has an anxious firm structure of bending which is not. And the exact waveguide-plunger motion is realized by preparing the big edge of compliance in the termination of the rigid-body fraction of a ribbon, and also directing in the shape of a sandwich by a silicon elastic body.

Alnico 750 is adopted as a magnet.
A uniform magnetic-flux distribution is secured by the density of flux density 7,400G., and the transient is raised sharply.

The low inductance power-feeding scheme which reduced the inductance to a super-high region sharply is adopted.
This suppresses an occurrence of few inductances of a power-feeding part, and the energetics of a high region is raised.

The wide band and the matching transformer of a low-loss design which made oxygen-free-high-conductivity-copper foil the multilayer sandwich volume are adopted.
The adoption with a linear initial permeability property of a permalloy core has realized high resolution.

The gilding treatment is performed to the termination.

The tone quality was pursued and the protection network with the fuse of an oxygen-free-high-conductivity-copper cap is adopted.

The table-lamp base which can be arranged as it is is attached on a cabinet.

Output

Rating of a mode
Form Ribbon tweeter
Input impedance 8ohm
Play frequency band 5kHz - 120kHz
The maximum input 100W (at the time of 5kHz and a -12 dB/oct network using)
Output power 50W (at the time of 5kHz and a -12 dB/oct network using)
Output sound pressure level 97.5dB/W/m
Cross over frequency - It is 5kHz or more at the time of 12 dB/oct.
The total magnetic flux 180,000Maxwell
Gap flux density 7,400Gauss
Protection network Fuse type
Dimensions Width 134x height 89x depth of 179mm
Weight 2.6kg
Adjunct Table-lamp base