Pioneer QM-800 (1972)

The Pioneer Quadraphonic Power Amplifier, model QM-800 is designed to serve in a 4-channel stereo installation, together with a 4-channel preamplifier, 4 speaker systems and one or several program sources. Engineered for highest sound fidelity, it will open up a whole new world of "environmental sound."

DIRECT COUPLING OF ALL STAGES

Direct coupling of all amplifier stages greatly improves phase characteristics and permits an extremely wide frequency response down to near-DC. A load-regulated power supply unit is employed, and output power is higher than will ever be required.

LEVEL METERS FOR ALL FOUR CHANNELS

To obtain optimum sound balance in a 4-channel system, four separate level meters are provided. Moreover, the meters sensitivity can be adjusted in three stages (0, -10 and -20 dB) to permit accurate readings at all volume levels.

ADJUSTABLE lNPUT SENSITIVITY

As the power amplifier's input sensitivity can be adjusted in 6dB steps (at 0.5, 1 and 2 volts), it is easy to match with any preamplifier.

SPECIAL HIGH-RANGE SPEAKER OUTPUTS

ln addition to the four normal, full-range speaker terminals, a set of high-range speaker outputs are provided. The QM-800 can be used as an exclusive high-range amplifier in a multi-amplifier installation.

PERFECT PROTECTION OF OUTPUT STAGE TRANSISTORS AND SPEAKERS

The output transistors are protected from damage (in the case of overload or short-circuits in the speaker leads) by a dual system of relay and DC drift voltage detector circuits. The latter also guard against possible speaker damage by DC current.

UNIOUE PIONEER EXTERIOR DESIGN

The front panel is attractive as well as logically laid out. With its natural wooden cabinet, the QM-800 matches other Pioneer hi-f i components perfectly.

PROTECTOR CIRCUIT

Even if the power switch of the QM-800 is turned on, the speaker system will not operate for the first 5 to 8 seconds. This is because the QM-800 is provided with a circuit which protects transistor, speakers, etc. from possible damage due mainly to unexpected trouble.

If any of the speaker systems stops operating during a performance, or if mechanical noise (click, click, . . .) of the relays is heard continuously, a short-circuit in the speaker leads may be responsible. Turn off the power and check all speaker connections. Since the protector circuit is very sensitive, it may be activated if the power switch of the preamplifier combined with the QM-800 is turned on and off separately. It is therefore advisable to obtain AC power for the QM-800 from a switchable AC outlet of the preamplifier, as this guarantees simultaneous on-off switching of both units.

Specifications

POWER AMPLIFIER SECTION

Music Power Output (lHF):

280 Watts per channel at 4 Ω;

200 Watts per channel at 8 Ω

Continuous Power Output (2 channels driven):

42W + 42W / 42W + 42W at 4 Ω;

35W + 35W /3 5W + 35W at 8 Ω

Continuous Power Output (4 channels driven):

32 W x 4 at 4 Ω;

25 W x 4 at 8 Ω

Power Output in the range of 2OHz to 20kHz (2 channels driven):

32W + 32W / 32W + 32W (8 Ω, THD Less than 0.5%)

Harmonic Distortion: Less than 0.5% (Continuous power output)

lntermodulation Distortion: Less than 0.5% (Continuous power output)

Power Bandwidth (lHF):

5 Hz to 50 kHz (8Ω, 2 channels driven, THD Less than 0.5%)

10 Hz to 50 kHz (8Ω, 4 channels driven, THD Less than 0.5%)

Frequency Response: 5 Hz to 80 kHz, ±1dB

lnput Sensitivity/lmpedance (1kHz, Continuous Power output)

0,5 V/70 kΩ

1,0 V/110 kΩ

2,0 V/170 kΩ

Speakers: 4 to 16 Ω (FRONT, REAR, HIGH RANGE)

Damping Factor: 70 (8 Ω, 1kHz)

Hum and Noise (IHF): More than 90 dB

Level Meters: 0 dB = 35 W/8 Ω, (Sensirivity selector 0dB, -10d8 and -20d8)

SEMICONDUCTORS

Transistors : 39

Diodes : 37

MISCE LLANEOUS

Power Requirements:

110V, 120V, 130V, 220V and 240V (Switchable) 50/60Hz

Power Consumption: 400 W (Max)

Dimensions (W x H x D): 430 X 145 X 337 mm (16-15/16 x 5-11/16 x 13-1/4 inch)

Weight

Without package: 11,5 kg (26 lb)

With package: 13,5 kg (30 lb)