Pioneer M-22

The die-cast aluminum radiator, die-cast chassis employing class A stereo power amplifiers.

The streamer A class action is adopted. A class operation and is shed every idle current when no signal is still a lot of transistors, the method uses only transistors operating range with good linearity. A work-class power utilization is low, but increasing the amount of heat, the two push-pull output transistors are synthesized and amplified to obtain the same waveform and bottom, B strain and the switching amplifier is not salmon crossover distortion does not occur.

M-22 to A-level circuit is run, NFB removed the DC circuit capacitor amplifier configuration, the DC by the time constant of the formation of the loop without NFB, a flat phase characteristics were obtained through ultra-low, stable NFB operation are obtained. This A-class operation and streamer configurations DC amplifier,i realized the middle and high range and excellent bass response without distortion sense.

The M-22 was a pure Class A amplifier that was rated at 30 watts per channel. Pioneer stated in its Series 20 brochure: "Class-A circuits are used throughout to reduce distortion. If operated in Class-B the M-22 would deliver no less than 150 watts per channel--five times as much--with so-so distortion. The most sophisticated circuit construction yet developed by Series Twenty is reflected here, along with truly first-class parts and components to asssure you're getting the real advantages of such design."

Like the C-21 Preamplifier, the M-22 used metallized polyester capacitors and nichrome-vaporized, metal-coated resistors. Pioneer utilized a dual mono circuit design and component layout, with a massive power transformer for each channel, coupled with two equally large 22,000 microfarad electrolytic capacitors per channel. The left and right channel circuitry was mounted to large die-cast finned aluminum heatsinks. All this was mounted to a rigid die-cast aluminum chassis.

What was striking about both the M-22 and M-25 amplifiers was, of course, their appearance. Practically all amplifiers in the late 1970s and early 1980s were fully enclosed by sheetmetal on all sides, with a ventiated cover. Pioneer took the minimalist approach, indeed, a purely industrial design approach to the design of these amplifiers. All the key components were visible, with the left and right channel components grouped in a mirror image. This really appealed to audiophiles who truly are intrigued by the "innards" of their electronic components.

Specyfications

Integrated systems: Two-stage differential, PPdrive, two-stage Darlington, parallel PP. Net complementary OCL (A-class operation, DC amplifier configurtion)

Effective output (both ch driven): 30 W + 30 W (10 Hz - 30 kHz, 8Ω)

Harmonic distortion (10 Hz - 30 kHz, 8Ω):

RMS output: 0,01%,

15 W output: 0,005%,

1 W output: 0,005%

Intermodulation distortion (50 Hz: 7 kHz=4:1,8 Ω):

RMS output: 0,005%,

15 W output: 0,003%,

1 W output: 0,003%

Output bandwidth (IHF, both ch driven): 5 Hz - 100 kHz (strain rate of 0,01%)

Frequency: 2 Hz - 150 kHz +0 -1 dB(1W output)

Input: 1V / 50kohms

Output speakers: 8 ohms

Damping Factor: 60 (20 Hz - 20 kHz, 8 ohms)

SN ratio (IHF, A network) Short circuit: 106 dB

Semiconductor: Transistor: 44 pieces, Diode, other: 62 piece

Power supply: 100V - 220V, 50Hz/60Hz

Power consumption: 10W

Dimensions (W x H x D): 420 x 158 x 370mm

Weight: 22 kg