What is stereo?

There are now two system of high fidelity, monophonic (monaural) and stereophonic. Monophonic is a system that starts from one microphone and is fed through a single high fidelity set. Stereophonic is a double system. Two separate microphones are placed at different sides of the orchestra and two different systems are used to keep the two signals or channels separated. Two separate speakers are used, placed on different sides of you room. Stereo is much like 3-D photography, two slightly different sound reach your ears giving you a new dimension in sound.

H.H. Scott '59

Accuphase E-204 (1981)

The E-204 is a new 75W/channel high quality Integrated Stereo Amplifier which received the full benefit of Accuphase's outstanding separate amplifier design technology in its development. Its powerful output stage is built around MOS FET's which are regarded as the best power amplification devices available. MOS FET's ensure a big improvement in the brilliance of treble reproduction by eliminating notching distortion, making its low distortion measurements comparable to Class-A operation characteristics. Another big advantage of MOS FET's is their high durability and heat resistant properties, both important requisites for devices used in power amplifier applications.

The E-204 employs these superior MOS FET's about which more details are given in another section, in a complementary-symmetry push-pull ppwer output stage that delivers a high quality 75 watts of power into both channels simultaneously at 8 ohms over a frequency range of 20 to 20,000Hz, with less than 0,01% distortion.

Pure DC amplifiers are used in both the voltage amplifier and power amplifier sections which permit direct coupling between them to contribute to improved sound. Employment of DC Servo Control in both sections further guarantees stable DC operation.

A built-in, 26 dB Head Amplifier in the Preamplifier section makes possible direct connections of high quality MC cartridges that require the extra amplification boost to bring their levels up to that of MM cartridges.

In creating the E-204 a most rigid program of parts selection was followed to ensure that this amplifier would give forth outstanding expressive power of music. Rigid parts selection is a basic policy of Accuphase whose engineers are well aware of the fact that two amplifiers with identical electrical specifications do not necessarily produce the same sound. Long experience in the pursuit of perfection has taught them that high quality parts make the difference in amplifiers which have that special power to express music more brilliantly clearly and impressively.

This amplifier is equipped with many useful functions such as a -20 dB At

tenuator switch which is convenient to start off records, a Disc Input Impedance Selector switch, and a switch taht permits separation of the preamp and the power amplifier.

An LED is located above each of the four Input Selector switches on the front panel. One of them will illuminate to indicate the input source that is selected.


Power output (both channels driven, 20 - 20,000 Hz, no more than 0,02% THD):

90 watts at 4 ohms;

75 watts at 8 ohms;

38 watts at 16 ohms

Total Harmonic Distortion (both channels driven, 20 - 20,000 Hz, at any power output from 1/4 watt to rated power):

0,02% max. at 4 ohms;

0,01% max. at 8 ohms;

0,01% max. at 16 ohms

Frequency Response (Main Amp Input):

20 - 20,000 Hz; +0, -0,2 dB at rated power output,

1 - 300,000 Hz; +0, -3,0 dB at 1 watt power output

High Level input Frequency response: 20 -20,000 Hz; +0, -0,2 dB at rated power output

Low level input Frequency response: 20 - 20,000 Hz; +0,2, -0,5 dB at rated power output

Dampingg Factor: 80, 8 ohm load at 50 Hz

Intermodulation Distortion: will not exceed 0,005% at rated power output

Input Sensitivity and Impedance (IHF standard):

Disc 1/MM: 0,22 mV at 100 ohms, 47 kohms, 100 kohms;

Disc 2/MC: 0,011 mV at 100 ohms;

Aux, Tape, Tuner: 13,9 mV at 47 kohms;

Main Amp : 0,12 mV at 47 kohms

Maximum Input for Disc Input (0,01% THD):

Disc 1/MM: 200 mV RMS at 1 kHz

Disc 2/MC: 10 mV RMS at 1 kHz;

Output Level and Impedance:

Preamp. Output: 1,0 V rated input level, 200 ohms;

Tape Rec 1, 2: 120 mV at rated input level, 200 ohms

Voltage Amplification in Decibels

Main Amp Input to Output: 27,8 dB;

High-level Input to Preamp Output: 18,4 dB;

Disc 1 Input to Tape Rec: 36 dB;

Disc 2 Input to Tape Rec: 62 dB

A-weighted Signal-To-Noise Ratio (IHF standard):

Main Amp Input: 95 dB;

High Level Input: 82 dB;

Disc 1/MM: 80 dB;

Disc2/MC: 77 dB

Tone Controls:

Bass: 200 Hz; ±10 dB at 50 Hz; 500 Hz; ±10 dB at 100 Hz

Treble: 2 kHz: ±10 dB at 10 kHz; 7 kHz: ±10 dB at 50 kHz

Loudness Compensator (volume attenuation at -30 dB):

Comp 1: +6 dB at 50 Hz;

Comp 2: +10 dB at 50 Hz, +6 dB at 20 kHz

Subsonic Filter: 17 Hz cutoff 12 dB/oct.

Attenuator: -20 dB

Output load Impedance: 4 to 16 ohms

Semiconductors: 55 transistors, 11 ICs, 8 FETs, 42 diodes

Power Requirement: 100, 117, 220 and 240 V, 50/60 Hz

Power Consumption:

55 watts at 0 Signal output;

300 watts at rated power output into 8 ohms load

Dimensions (W x H x D): 445 x 128 x 370 mm ( 17-1/2" x 5-1/16" x 14-9/16")

Weight net: 13,6 kg (30 lbs)

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