For Sale: Pioneer M-22 amplifier - 30 powerful Class A watts - so it runs quite warm/hot. This is a stone cold classic amp - priced relatively low due to some cosmetic issues.Condition: See photos for condition. I would rate cosmetics at 6.5/10, performance at 9/10. There are no returns on this amp due to its age, but is guaranteed not to be DOA. Warning: Be very careful you don't accidentally remove the RCA's with power on! Description: This from the listing I purchased from a few years ago: "My cherished Pioneer M-22 amplifier. It is in perfect working order, and sounds amazing. If you are looking at this posting, you probably know all about this epic piece of Japanese industrial art. If you're not familiar with this amp, there is plenty of info online about it. Absolutely the best looking and sounding amp I have ever owned. The amp has been gone through by a career vintage hi-fi specialist about a year ago (family friend, wants to stay anon), and I had him replace all of the outputs with matched pairs of genuine n.o.s. Sanken transistors...not the Chinese copies found on eBay. All measurements were well within the factory specs. I have owned this amp for a long time, and only used it occasionally, driving a pair of Klipsch LaScalas. The detail and wide-open sound is simply amazing. Since it is a class A amp, it does get quite warm, and will definitely take the chill out of a cold room in the winter! Cosmetically, it does show some signs of wear...it's about 40 years old...but still looks awesome. Amp is in excellent working condition. Cosmetically, it looks very good. There are some small scuffs and scratches here and there, but looks very nice overall. It's time for someone else to enjoy it." Shipping: $100 in the continental US only. I don't charge for boxes, foam, tape, labels, travel to UPS/FedEx, or my time, so please don't ask for free shipping if you make an offer -"I'm not amazon." This amp will weigh about 65 lbs when packed." Thanks for looking. Specs and more below. From various reviews and discussion of the M-22 (your results and perceptions may vary, of course): from the stereo no mono blog: "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 assure 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."
Pioneer M-22 / M-25. Epic Japanese gear from the late 1970s. Pioneer should have never stopped making them. All it took was the first few seconds of the Graceland CD for me to realize that it was a better amp than the Hegel. The presentation is slightly different with the Hegel being sharper and more incisive with its attacks, vaster sound stage, and more volume at the extremes. However, the M-22 blew away the Hegel terms of microdynamics and plankton, and even slightly surpassed it with macrodynamics. Surprisingly, the M-22 was also clearer sounding than the Hegel, despite the Hegel destroying everything else before it in terms of clarity (Crest CA2, Vincent SP-331, NuPrime digital abomination, Parasound A23, etc.) The M-22 is the low wattage version, I think 30 watts, all Class A. Yes, the M-22 is magical. It is the best solid-state amp I have heard thus far. Super immediate and engaging.
The M-22 dwarfs the Vidar. I started with the Vidar. I set the volume to my normal listening level. Then I went to YouTube, played an 80 Hz tone, and noted the dB level from my listening position. I played a few songs from my "Test" playlist in Roon. Then I switched all the cables over to the M-22 and volume matched using the same 80 Hz tone. I then played those same few songs from my "Test" playlist. The difference was palpable. I couldn't believe how much better the M-22 sounded to me. I double checked the volume matching just to make sure that wasn't the reason for the difference. I am having a hard time isolating the differences because everything about the music sounds better. The music is much more full sounding without losing any detail or clarity. The bass is full and strong yet is controlled and clear. There is no muddiness in the bass. The mids are incredible. The highs are clean and strong without any harshness or brightness nor any roll off. For the overall sound, the word "lush" comes to mind. Maybe a bit "wet" as Marvey defines it. But all the while sounding natural. The Pioneer M-22 is the best solid-state amp I have heard so far. The M-22 limitations have to do with its limited power. Also, the the edges of the attacks are a bit rounded compared to the likes to the Hegel H2, although transients are just fast. No necessarily a negative, just different and a matter of component matching that works. Super detailed, sweet mid range, extends deep in the bass and sparkles in the highs, and overall very engaging. I had so much fun listening to it, I wanted to keep going all day. Switching back to my old Odyssey amp, everything sounded muddier in comparison. That afternoon I took it to a friends house to compare the M-22 to his 300b SET tube amp, and it totally held it's own! The sound quality was on par between the two amps with the usual variations you'd expect between SS and tube. The M-22 was a touch drier compared to the SET, but the detail and separation between instruments was extremely clear. The SET amp was more lush, but I felt like the overall presentation was a little more more smeared and smoothed over. Both were excellent though. Differentiation of timbre etc in the treble is really good. Maybe better than anything else I heard so far.
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 ventilated 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.” Specifications: 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 http://stereonomono.blogspot.com/2011/06/pioneer-m-22.htm
“The M-22 is one of those rare products that come along once in a decade when a company has the luxury of assigning its top engineers to a long-term R&D project. The service manual alone is a work of art, not to mention the construction of the amplifier and its circuit design. All first rate, no compromise efforts. The downside is that the amp runs hot, and needs to be checked out on a regular basis. Every 3-5 years at this point in its life cycle. They are all vintage at this point, and they all suffer similar problems with heat stress, oxidation, capacitor aging, etc. So they all need to be checked and maintained. The purchase price is just the beginning in many cases. A full restoration will cost more than the purchase price, so my advice is to just do what is necessary to keep it reliable, and get it checked out on a regular schedule." • Extreme detail and clarity: check
• Treble extension: check
• Delicate touch: check
• Density: check. Thickness is there when appropriate (male vocals, strings, etc).
• Bass control and punch: check
• Inaudible noise floor: check
• Correct treble timbre/texture: MASSIVE check. The antithesis of homogenous Sabre digimush shit. (note: timbre/texture is my personal catnip)
• Realism, depth and 3D-ness: BIG check also. Appropriate width/depth/height all in proportion to each other. Whatever magic this does is also very much complementary to good crossfeed, although it is 3D even without crossfeed to a lesser extent. This is definitely new.
• Moderately shitty recordings: check. Because of the clarity, if some badness is there, you will hear it; but on the other hand, it seems to be able to make these recordings a lot more listenable overall, much like a good multibit DAC in that respect.
• Value: MASSIVE ... Joined the M-22 club over the weekend. It's mostly @sphinxvc's setup, which we used to compare my M-22 to his First Watt F3. Going from the F3 to the M-22, the most immediate difference is with the cleanliness of the treble, overall resolution, and the improvements in imaging. The M-22 was able to get louder and had more control over the bass due to its higher power output as well. Overall it's an extremely solid SS amp if you can find one in good condition or price, and if you have the appropriate speakers (90db+ at 8 ohms). M22 sounded like a more powerful F3 to me. It's rare I find something to outperform the F3, but the latter's lack of power and gain was obvious on the 91db Devore Nines. To me, the difference basically came down to slightly less-mid centric tonality on the M22, and better control/tightness and presence in the bass. I think some of the other things @thegunner100 mentioned are byproducts of those features, which is to say they aren't as prominent. (The XA-30.8 should have better edge definition, inner detail, and punch. I'd suspect the XA-30.5 to be the closer comparison to M-22.)
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