|
|
|
|
Pioneer M-22
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.
The M-22 had a total of 44 transistors and 66 diodes, for a total of 110 semiconductors. It measured 16.53 inches wide, 6.03 inches high and 14.56 inches deep. Its weight was 48 pounds, 8 ounces. M.S.R.P was $790.00. |
Article:
|
|
|
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."
And this is what Pioneer had to say specifically about the M-22's performance: "Not
to be overlooked is the extremely wide power bandwidth offered in the M-22: 5Hz
to 100kHz, both channels driven, 0.01% THD. Note also that the frequency
response is an amazing 2Hz to 150kHz, + 0dB/1 dB at 1 watt, and that the
signal-to-noise ratio is a high 106 dB (IHF short-circuited A network."
At its full power output of 30 watts into 8 ohms, this amp had no more than
0.01% THD between 10 Hz and 30kHz! Class A indeed!