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

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

  1. skem

    skem Friend

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    Not being too original here -- but this just arrived. The condition was so good I couldn't pass it up. Also... had to get it so @porkfriedpork can listen to his HE-6 when at my place at an appropriate volume. The restoration project begins soon.

    [​IMG]

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  2. msommers

    msommers High on Epipens

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    Fuck that is mint!
     
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  3. winders

    winders Worst poster on SBAF (not a joke)

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    Much nicer looking than mine!
     
  4. bengo

    bengo Friend

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    Lol, I find the main issue with this amp is that it makes me want to listen at inappropriate volumes...
     
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  5. PTS

    PTS Friend

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    Got my M-22 back from Scott Frankland a week ago, and have been running it in over the past few days. Sounds fantastic, better than ever! Turns out the amp had been restored before I bought it, although probably some time ago. Aside from the repair and cleaning, the only mod was to have some Mundorf caps installed (detailed in Scott's last paragraph). I figured this info may be helpful to others that are looking to have their M-22 serviced.

    -----

    "All of the connector pins (about 5 dozen) have been polished, and Deoxit has been applied. I plan to do the same for the RCA jacks, and anything else that shows oxidation.

    The parts replaced by the previous tech are good parts, and I see nothing done that is not within spec. The parts replaced are all electrolytic caps, which have a finite lifespan. So you are in good shape for another 30 years, or until the big filter caps up top get leaky. Could be awhile.

    The only other parts that have a wear factor are the 4 trimpots for bias and DC offset. These are still functional, but they will probably be the next item to give trouble. Could be years. Same goes for the relays. They are not causing problems with signal dropouts at this point, but they will at some point in the future. Again, it could be years.

    The resistors all look good and therefore should not wear out for many decades (or centuries) unless they are overloaded by a parts failure. Same goes for the transistors and power transformers.

    The Mundorf caps will be connected in parallel with the big filter caps up top. Large caps are less able to bypass high frequencies than smaller caps, so it has been customary in modern times to add a small, high-quality film cap to large electrolytics to shore up their high frequency performance."

    -----

    Yesterday I sold my Tekton Lores and used the M-22 in my chain during the audition. The buyer's jaw dropped when he heard the music, which made me question if I should be selling them. Tried them again with the Bhavas today, which sound great but are a little more fussy about room positioning compared to big tower speakers. Still have to fine tune the sound.
     
    Last edited: Feb 5, 2018
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  6. Diesel Mat

    Diesel Mat Rando

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    This only comes in 100-110 volts?
    Apologies if this was asked before.
     
  7. thegunner100

    thegunner100 Hentai Master Chief

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    There's a 120v version as well.
     
  8. Diesel Mat

    Diesel Mat Rando

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    Ah too bad i was hoping there was a 220 version
     
  9. alubis

    alubis Acquaintance

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  10. bengo

    bengo Friend

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  11. frenchbat

    frenchbat BritishBat's arch enemy - Friend

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    [​IMG]
     
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  12. Habano

    Habano Rando

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    Hello everyone, after reading this thread, I am considering joining the club.

    I am looking at this:

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    I have a few questions:
    1) the seller said that the bias inside has been set and the offset of the terminals have been checked and adjusted. Nothing inside needs to be changed. Should I factor in the cost of an inspection/restoration anyhow?
    2) I am thinking of getting a Saga or using my Jotunheim as a preamp. What might be the difference in SQ? The Saga with remote seems pretty cool.
    3) I am considering a Holo Spring or an Yggy as a DAC to go with the M-22. What difference could I expect in terms of sound quality? I am still thinking about the loudspeakers.

    Thank you for your help!
     
  13. AdvanTech

    AdvanTech Friend

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    1) yes. My seller said everything worked fine and didn’t need to be restored, but it sounded limpdick until I did. It’s so old that caps will need replacing.

    2) Members here have not recommended a Jot as a preamp. If you’re going to get such a wonderful amp you should get a proper (and the Saga is really great!) preamp.

    3) I’ll have to defer to other members

    4) wanna PM me for my restored M-22? :)
     
  14. Habano

    Habano Rando

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    Thanks!

    1) OK, that's what I feared. With the cost of a restoration, the price of this unit seems a bit stiff

    2) Saga it is then. My Jot will remain on headphones duty

    4) PM sent
     
  15. AdvanTech

    AdvanTech Friend

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    I have been emailing Steven at PranaFidelity about another SBAF member and I's impressions pairing more powerful amps than our M-22's with our Bhavas, and noticing that they seem to 'wake them up' (especially with regard to slam/impact).

    I asked him if purchasing and restoring an M-25 might be the way to coax this kind of behavior out of our speakers while still retaining that vintage Pioneer Series 20 magic, and he said that the M-22 could be upgraded with a stouter power supply as "...there is more that can be brought out of that amplifier." @purr1n Might this be true? Has anyone else done it?
     
  16. bengo

    bengo Friend

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    You are kidding, right? Have you seen the smoothing caps on the M-22? The trafo is also pretty big.
     
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  17. purr1n

    purr1n Finding his inner redneck

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    Can the Bhavas be biamped? Run M-22 on the tweeter and something more powerful with bass grip but cheap like Vidar on woofers? You can pad down gain differences with JDS OL or Schiit Sys.
     
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  18. 9suns

    9suns [insert unearned title here]

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    It's a difficult and expensive route, but what about removing the passive crossover and using the matching Pioneer D23 active crossover, C21 preamplifier and two M22 amplifiers? That would be a fun experiment!
     
  19. purr1n

    purr1n Finding his inner redneck

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    Not really because the passive crossovers are specific to the Bhavas and "passive crossovers" are more than that: they are EQ and xover slope shaping circuits.
     
  20. AdvanTech

    AdvanTech Friend

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    That sounds ideal but they only have two binding posts.
     
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