Pioneer M-22 Power Amp - Epic Japanese Gear From the Past

Discussion in 'Power Amps' started by Armaegis, Mar 30, 2017.

  1. bozebuttons

    bozebuttons Friend

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    Just put in in your system & Listen to it.
     
  2. Drakkard

    Drakkard Facebook Friend

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    Oh wow, did not expect to see such thread here :) I have Pioneer A-0012, which is also known as A-27, and love it. The internet says its essentially C-21+M25 in a single chassis. It works as poweramp now, as I found better pre-amp to use with it.
     
  3. 9suns

    9suns [insert unearned title here]

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    Speaking about epic gear from Japan...

    [​IMG]

    Accuphase A-36 can be bought second for less than 3k in Japan, it would need voltage conversion, but that's nothing compared to a complete refubrish for a 30 years old Pioneer unobtanium amp.
     
  4. winders

    winders boomer

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    The refurbished Pioneer M-22 I bought arrived today with the morning mail. It is a heavy amp at 48.5 lbs. Its gorgeous!

    I setup the Vidar and M-22 on the floor in front of my rack so it would be easy to swap cables and let both amps warm up for 30 minutes. 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. Don't get me wrong. The Vidar amp sounds great. But it pales in comparison...at least so far.

    I immediately thought that I must be experiencing "expectation bias". What else could explain the significant difference I was hearing?

    I decided to setup a comparison session for my wife. She is a guitar player and is very musical. But, she has never paid any attention to audio equipment and thinks I am a little bit crazy buying all the audio equipment I have. I explained that I wanted her to listen to a couple of songs with each amp, not knowing which amp was used, and then tell me which she like better. She said I was wasting my time as she thought she would not be able to tell the amps apart.

    I had her listen to two songs: "Gold" by Jonathan Stewart and "I.G.Y." by Donald Fagen. The first song is one she requested and the second is one I think exposes strengths and weaknesses audio systems. I flipped a coin and Vidar got to goes first. She listened to both songs and commented that they sounded great. I then switched to the M-22, volume matched, and had her listen again. About 30 seconds into "Gold" she had me stop the music. She said the second amp sounded far better than the first. I continued the two songs. After they finished, she said she was surprised at how much better the second amp sounded and was even more surprised that she could actually tell the difference. She likened the difference to hearing music live versus on the radio. She told me to keep the second amp, whichever one it was. Funny, she never asked which amp was which.

    I have a lot more listening to do. But, if initial impressions are any indication, I will probably have a Vidar for sale soon!

    Edit: I almost forgot. The gain of the M-22 amp is somewhat less than Vidar as the tube hum is quieter. About 3dB less if measured 2 inches from one of the midrange driver dust caps. When volume matching, I didn't have to turn the volume knob all that much to match sound level. Maybe 3 or 4 steps on the relay. This is surprising to me considering Vidar is 200 watts per channel and the M-22 is 30 watts per channel. The M-22 has more enough power. The volume can go well past extremely uncomfortable!
     
    Last edited: Aug 25, 2017
  5. PTS

    PTS Friend

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    Great comparison, very helpful. Were you using tube mode on the Freya for extra gain with both amps?
     
  6. PTS

    PTS Friend

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    Interesting that Pioneer released different variations of the same design, including an integrated unit. Is the C-21 pre-amp side not very good?
     
  7. winders

    winders boomer

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    Thanks. Yes, I used Freya's tube gain mode for the all the comparisons. I prefer the sound I get with the tubes. For the comparisons, I used Sylvania 6SN7GT tubes in the output stage and Sylvania 6SN7GT "Bad Boy" tubes in the gain stage. That's as good a tube setup as I have...
     
    Last edited: Aug 25, 2017
  8. Drakkard

    Drakkard Facebook Friend

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    A-0012 is the 100v version for domestic Japanese market, A-27 is the 220v exported version as far as I know. All this units represented top of the Pioneer line-up in 1978-1980.
    They were later replaced with Z1 series: http://i.ebayimg.com/00/s/MTA2M1gxNjAw/z/hl0AAOSwPc9WykTu/$_3.JPG

    Yes, I found pre-amp section to be a bit muddy and soft compared to my custom-made pre-amp. It still sounded great and much better than my previous amp (also vintage Pioneer A-717) from the start.

    I actually want to change it for M-22 or M-25 at some point... I just adore how they look :)
     
    Last edited: Aug 25, 2017
  9. foo_me

    foo_me Friend

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    Wow, glad to hear that the M22 performed so well!
    And thanks for the comparison.
    Correct me if I'm wrong but I believe Vidal is 100 watts into 8 ohms and m22 is 30 watts /8 ohms.
     
  10. foo_me

    foo_me Friend

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    Btw @winders, what speakers are you using with them?
     
  11. winders

    winders boomer

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    Yes. Vidar is 100 WPC into 8 ohms and 200 WPC into 4 ohms. My speakers are 4 ohms.

    I have Tekton Design Double Impact speakers. These speakers are 98.82dB [email protected] into 4 ohms, which corresponds to 95.8 db [email protected] into 4 ohms. They are quite efficient.

    I am quite surprised at how easily this 30 WPC amplifier is able to drive my speakers. As I said previously, the M-22 has less gain than Vidar and a whole lot less power. Yet the volume knob position is only like 4 clicks more with the M-22 versus Vidar.

    You should have me come up to your place so you can try the Vidar amp before too long. As I play more and more of my collection through the M-22, I am more and more inclined to sell the Vidar!
     
  12. PTS

    PTS Friend

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    For those who got their M-22 restored - who did you use and how much did you pay?

    Currently keeping an eye out for a decent looking M-22, although eBay looks like a crap shoot right now. All overpriced and either broken or suspect. Looking at the sold listings I see there have been a few going in the $650-850 range.

    Bringing one back from Japan (I plan on going again this year) will be it's own pain in the ass, but undoubtedly cheaper if I decide to deal with the hassle.
     
  13. Hrodulf

    Hrodulf Prohibited from acting as an MOT until year 2050

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  14. winders

    winders boomer

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    I have some other no-musical observations to make about the Pioneer M-22 compared to the Vidar.

    The M-22 runs a lot warmer than Vidar. Hot in fact. So hot that I can't keep my hand on the heatsinks for very long. This is to be expected since in runs in Class A mode only. Because of this, I suspect I will turn the amp off when I am not going to be listening to music any time soon. It will certainly be turned off over night. Unlike Vidar, the power switch is on the front so it is easy to turn on and off.

    There is no hum of any kind in the speakers when the M-22 is on and Freya is off or in passive and JFET modes. With Freya in tube gain mode, there is a hum but it is much quieter than when Vidar is used. With Vidar powered on, there is always a hum in the speakers whether Freya is on or off. If I left Vidar on, I could here the hum in the speakers when I would walk into the listening room.

    While I very much like the industrial design on the M-22, I don't like the interconnects and cables plugging into the front of the unit. It is untidy and it doesn't really offer any advantage.
     
    Last edited: Aug 26, 2017
  15. bobboxbody

    bobboxbody Almost "Made"

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    Has anyone heard/owned a Mitsubishi DA-A30?
     
  16. ButtUglyJeff

    ButtUglyJeff Stunningly beautiful IRL

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    Sounds like you're describing Class A operation. Is the M-22 straight Class A?
     
  17. winders

    winders boomer

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    Yes, it is a straight Class A amp.

    I am listening to Fritz Reiner's "Scheherazade" through it right now. I have never been so moved by a piece of music. It sounds spectacular!
     
  18. winders

    winders boomer

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    I have been looking for the gain specs of the Pioneer M-22 amp so I could compare it to the gain Vidar has. Why? Well, I have been trying to figure out why there is no speaker hum with the M-22 while there is quite a bit with Vidar in otherwise identical configurations. Initially, I thought that it was due to the M-22 having significantly less gain. That premise seemed unlikely when I discovered during volume matching that there was not that much difference in knob position between the two amps when matched.

    Someone on another forum made me aware that you can calculate gain if you know certain information. I know the watts, load resistance, and input sensitivity of the M-22. The M-22 has 30 watts with a load resistance of 8 ohms and an input sensitivity of 1 volt. I can post the formulas if anyone is interested but the M-22 has 23.8dB of gain. Vidar has 27dB of gain.

    So, I am curious. When using the M-22, the speakers are silent with Freya off or on in passive or JFET mode. When using Vidar, the speakers output an audible hum with Freya off or on in passive or JFET mode. I don't think a 3.2dB gain difference explains the stark difference. If the M-22 had 10dB less gain. I would perceive that as half the volume of the hiss, right? So, if it were just the gain, I should still hear some hiss.

    Thoughts?
     
  19. ohhgourami

    ohhgourami Friend

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    I don't know what's the exact cause but from experience in my gear journey that high quality gear will have no audible noisefloor regardless of power output or gain.

    If the Vidar has an audible noisefloor then...
     
  20. winders

    winders boomer

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    I was quite disappointed in the hum from Vidar when I got everything setup. I even ordered a new set of RCA interconnects from a different vendor (BJC) to make sure it wasn't an interconnect issue. It wasn't. When I tried Vidar as a monoblock the hum was a little quieter with Freya in passive and JFET mode but louder in tube gain mode.

    This would be less of an issue with less efficient speakers. But my speakers are quite efficient at 98.82dB [email protected]
     

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