Audio Database


41,800yen(around the 1970 time)

The Integrated Amplifier of PB series which upgraded AU-555 and renewed the description and the design.
The whole page consists of silicon transistors.

The SEPP-ITL-OTL scheme of the pure complimentary darlington circuit which adopted the silicon transistor as the power transistor is adopted.

In order that an electrolytic capacitor may avoid the ill effect which it has on a music signal, as much as possible, using a hardwired-connection circuitry, a capacitor is lessened, and a required fraction makes a circuit impedance high and is using the Mylar capacitor.
Moreover, electrolysis connected the Mylar capacitor to the surely required fraction in parallel, and has improved the high region property.

The triple tone control of Bass, Midrange, and Treble is carried.
Moreover, since it is an it1 step type control, a special NetWare program and a more exact correction of a room acoustic can be performed.

Especially a preamplifier part uses the low-noise silicon transistor sorted out, and makes the noise small.

All the amplifying circuits from the first rank to the final output stage are constituted from NF amplifier, and the frequency characteristic, distortion, and S/N are improved.

A preamplifier part and a main-amplifier part are detachable.

The ripple-filter circuitry which became independent, respectively is attached to the main amplifier and the preamplifier power source.
A hum component is intercepted completely by this and the power source is stabilized.

Two speaker outputs are carried.

Functionalities which can be simultaneously monitored at the time of a low NF type filter, a high filter, a loudness control, and a sound recording, such as a tapes monitor circuitry and a headphone termination, are carried.

Rating of a mode
Form Stereo Integrated Amplifier
<Main-amplifier part>
Output power
Music power (IHF) : 85W (4ohm)
60W (8ohm)
Effective output : 33/33W (4ohm)
25/25W (8ohm)
THD 0.5% or less (Output power)
Cross modulation distortion (SMPTE, 60Hz:7000Hz=4:1) 0.5% or less (Output power)
Power Band Width (IHF) 20Hz - 40000Hz (8ohm)
Frequency characteristic 20Hz - 40000Hz, }1dB
Channel separation 60dB or more (1kHz, Output power)
A hum and a noise (IHF) 100dB or more
Input sensitivity/impedance 1V (Output power) / 100 kohms or more
Load impedance 4ohm-16ohm
Dumping factor 50 (8-ohm load intensity)
<Preamplifier part>
Output voltage Maximum output: 5V
Output power: 1V
THD 0.1 (Output-power voltage) or less
Frequency characteristic 20Hz - 30000Hz, }1dB
Channel separation (1kHz, Output power) Phono1, 2:45dB or more
Tuner, AUX: 50dB or more
A hum and a noise (IHF) Phono1, 2:70dB or more
Tuner, AUX: 80dB or more
Input sensitivity/impedance (1kHz, Output-power voltage) Phono1, 2:2mV / 50kohm
Tuner: 180mV / 50kohm
AUX: 180mV / 50kohm
Tape Play(Pin): 180mV / 50kohm
Tape Recorder(Din): 180mV / 50kohm
Sound-recording output (1kHz, input voltage) Tape Rec(Pin):180mV
Tape Recorder(Din):30mV
Equalizer Phono:RIAA NF type
Control Bass: 30Hz, }12dB
Midrange: 1.5kHz, }5dB
Treble: 15kHz, }10dB
Loudness: +3dB (10kHz), +8dB (50Hz)
Switchpoint A low filter: 50Hz-8dB
A high filter: 10kHz-7dB
Power source 100V, 50Hz/60Hz
Power consumption 130W
Dimensions Width 395x height 127x depth of 278mm
Weight 8kg