Audio Database

The

Accuphase E-303
245,000yen (July, 1978 release)

Description
 
The stereo Integrated Amplifier which pursued a good reproduction sound.
Head amplifier is built in so that MC cartridge may connect directly.
Four MOS FET was constituted from a parallel push pull, and 130 W/ch is realized.

All the magnification stages consist of perfect symmetrical type push pull circuits from the entrance of head amplifier to the final of MOS FET.
although this circuit needs the number of parts close to twice compared with the ordinary system -- base -- since it excels in the characteristic, especially a linearity, it has the merit that a low distortion is realizable by a little NFB.
Thereby, TIM distortion which degrades sound quality has improved sharply.

All the unit amplifier is considered as direct-current composition.
Moreover, direct-current cut condenser of NF loop which needs large scale was removed, and coloration is removed.
Newly developed direct-current servo system is adopted, it succeeds in suppressing direct-current drift, direct-current-ization of the difficult tone control circuit is realized, and it operates as direct-current amplifier also in the time of tone control use.

In order to lessen the coloration by a condenser further, the ICL system which removed the input condenser of each unit amplifier is adopted.
For this reason, the number of the condensers during the output from AUX and Tuner is one.

The input constituted the super-low noise transistor from a differential push pull, and has realized the low input conversion noise level of -150dBV conjointly with low impedance-ization of NF loop. Moreover, the large dynamic range which does not generate clipping in any MC cartridges is secured.
Moreover, since it does not have a condenser, there is no coloring by a condenser.
the head amplifier can be easily adapted also at the time of 2 arm use -- as -- DISC1 and 2 -- even a switch comes out also to which input, and it changes simply.

Equalizer amplifier enlarges the current of a final transistor, and makes it Class A operation, an Output load impedance is lowered, and the noise which also forms NF loop into low impedance and generates it by this in a difference input circuit is reduced sharply.

The high efficiency and the low leakage flux type which adopted CI core are adopted as a power transformer.
This CI type of core is the same as the form currently used for the pillar-shaped transformer of the intense home power source of load fluctuation, since winding wire is used as 2 division balance type, it is few, and is efficient and the leakage flux is also excellent also in rate of change.

Expansion of a tone control function is measured and the turnover changeover switch is carried.
Thereby, as for Bass, 200Hz, 500Hz, and Treble can choose 2kHz and 7kHz now.
11 contact rotary switch can perform the variable method, and it can keep change of a step exact.
Moreover, the tone control ON/OFF switch is also carried.

Hearing impression at the time of the amount reproduction of low-pitched sound is rectified, and the loudness Compensation switch which prepares energy balance is carried.
Three kinds of curves can be chosen according to the characteristic of a regeneration level or a listening room.

The Subsonic Filter of 17Hz and 12 dB/oct is carried.
The sound quality at the time of ON is thought as important, the input active device of high-level amplifier is utilized, the active filter is formed only by the addition of CR, without adding an active device, and sound quality degradation is suppressed.

The power output meter is carried and the Direct reading of the output can be carried out with logarithm compression type peak directions.

An Attenuator switch of -20dB useful when discovering the start point of a record,When not using a DISC input impedance changeover switch and a tape recorder, a recording output circuit is cut, and the function in which the switch which prevents distorted generating, the separate switch which uses them making a preamplifier and power amplifier become independent, etc. are useful is carried.

There is an optional wood case.

リアパネルとウッドケース装着時
内部構造

Rating of a mode
Form Stereo Integrated Amplifier
Output power
(at High Level Input, the time of both channel operation)
20Hz - 20kHz, 0.02% or less of a distortion
4ohm load: 180 W/ch
8ohm load: 130 W/ch
16ohm load: 65 W/ch
THD (for 20Hz - 20kHz) High Level Input->Output: Less than 0.02% (at the time of an Output power)
High Level Input->Pre Output: Less than 0.005% (at the time of an Output power)
DISC(Head Amp:OFF) ->Tape Rec Output: 0.005% or less (at the time of 6V output)
DISC(Head Amp:ON) ->Tape Rec Output: 0.01% or less (at the time of 2V output)
IM distortion (at the time [ High Level Input ] of an Output power) 0.01% or less
Frequency response High Level Input: 20Hz-20000Hz+0 -0.2dB
DISC Input: 20Hz-20000Hz+0.2 -0.2dB
Dumping factor 80 (8-ohm load, 40Hz)
A rated input / input impedance DISC1(Head Amp:OFF): 2.5mV/100, 47k and 82k, 150kohm
1 (Head Amp:ON):0.125mV of DISC(s)/100 ohms
DISC2(Head Amp:OFF): 2.5mV/47kohm
2 (Head Amp:ON):0.125mV of DISC(s)/100 ohms
High Level Input: 160mV/47kohm
Main Input: 1.3V/47kohm
The DISC maximum input (0.005% of a distortion, 1000Hz) Head Amp OFF:300mVrms
Head Amp ON:15mVrms
An Output power/Output load impedance Pre Output: 1.3V/200 ohm
Tape Rec Output: 160mV/200 ohms (in the case of DISC)
Headphones: 0.32V/conformity impedance 4-32ohm
Gain Main Input->Output: 27.8dB
High Level Input->Pre Output: 18.4dB
DISC Input(Head Amp:OFF) ->Tape Rec Output: 36dB
DISC Input(Head Amp:ON) ->Tape Rec Output: 62dB
S/N / Input conversion noise
(at the time of input short-circuit, an IHF-A curve, and a rated input)
Main Input:115dB/-112dBV
High Level Input:100dB/-116dBV
DISC Input(Head Amp:OFF):86dB/-138dBV
DISC Input(Head Amp:ON):72dB/-150dBV
Volume control linkage error Less than 1dB
Tone control
Low-pitched sound 500Hz : ±10dB (100Hz)
200Hz : ±10dB (50Hz)
2dB step
2dB step
Loud sound 2kHz : ±10dB (10kHz)
7kHz : ±10dB (50kHz)
2dB step
2dB step
Loudness Compensation COMP1:+6dB(50Hz)
COMP2:+9dB(50Hz)
COMP of 3:+10dB (50Hz), and +4dB (15kHz)
(with volume control and -30dB)
Subsonic Filter 17Hz, -12 dB/oct
Attenuator -20dB
Power meter Logarithm compression type peak level directions
dB and the output Direct reading at the time of 8-ohm load
Load impedance 4-16ohm
The semiconductor used 113Tr, 18FET, 2IC, 39Di
Power source 100V, 117V, 220V, 240V/50Hz, 60Hz
Power consumption At the time of no inputting: 100W
At the time of an 8ohm load Output power: 490W
Dimensions the width 445x height 160(piece -- it includeds) x depth of 370mm
Weight 20kg
Option Wood cabinet A-8 (\15,000)