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Major Surgery Revives 35 Year Old Amp


agile_one

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Back in the '70s the amp wars were on, and Japan (Sansui, Pioneer, and others) challenged the burgeoning U.S. HiFi (yes, that's what it was called back then) stalwarts Marantz, Fisher, Scott, McIntosh, and Harmon Kardon with high quality, low cost premium gear. Heck, even Sony had a presence in high end, high quality iron in those days.

Much of that gear is revered today, including the relatively exclusive Pioneer Series 20 line. I was recently fortunate to land a Series 20 M-22 Amplifier - 30 watts, Class A, and as sweet as any amp I have ever heard - right up there with any Pass Labs, Krell, McIntosh, or Levinson. When I got it, it was in very good (7.5/8 of 10) cosmetic condition, but a bit lacking in sonics. This wouldn't do for a rare beauty from 1976, so I found some guys in Illinois who are electronic engineers and restore old gear as a hobby. Off to them the M-22 went for a full restoration.

6 weeks, many parts (all diodes and capacitors in power supply, trim pots, all relays, new iec power cord, and correct bias setting after 48 hour burn in, and safe UPS journey home), I am thrilled and ecstatic with the outcome. Many of you know that I am a K1000 holdout in spite of the wave of JH13, HD800, Ortho, Omega w/ BH II fotm madness over the last few years. My steadfastness has been rewarded. This restored M-22 is as good as (note, I resisted saying better then) any K1000 amp I have ever heard (yes, bring me your Pass Alephs, even your Zandens ... I will spit you out ... ymmv :) ). I am just so pleased with this 35 year old classic, that I had to share.

Link (other great old stuff on those sites) ...

Pioneer M-22 Amplifier

Photos of my M-22 ...

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Fortunately, the huge 33,000 mF output caps tested as new ...

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Trafos were in perfect condition

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Nameplate is a bit banged up, but do you see one on today's gear?

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Edited by agile_one
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John ... I would kill to hear this with good speakers. If my car weren't so dam'n full for this trip north, I'd bring it, and let you use while I am in Maine. Wait, massive packing reorg is now in progress ... Becky, what are you thinking bringing those gifts for kids and grandkids? Get real, I got an amp to haul to jp. Stay tuned ...

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Re: ortho fotm, most orthos were made around 30 years ago, right around when this amp was made. This Pioneer looks absolutely gorgeous and is a true man's amp.

Good point, mpi, and I suspect this amp and those old orthos would be a lovely combo. Might need an impedance box, but, I've got the amp, if you've got the orthos ... bring beer. :)

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Very lovely indeed; congrats, Gene. Any "before" pictures?

Thanks, Todd. "Before" pics would be pretty much the same as after from the outside. It was in decent cosmetic shape to start with. This is a pretty straightforward and pure design - the sound quality is a result of clean circuit design and super premium components. They don't make transformers, heat sinks, and tomato soup can sized caps like these any more. Much like those 1000+ year old Samurai swords - the core of this thing was built to last.

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on a side note the M25, a 150 A/B amp is on audiogon at the moment about 1.75 hours from my front door. I love the looks of this amp. must resist, must resist.

Gene how costly was the rebuild?? Feel free to pm if you do not want to publish that data

Forget resisting John, DEW EEET!

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Very purdy but show us the real porn, i.e. the inside. :)

Birgir ... one of these days I'll get ambitious and open her up for photos.

on a side note the M25, a 150 A/B amp is on audiogon at the moment about 1.75 hours from my front door. I love the looks of this amp. must resist, must resist.

Gene how costly was the rebuild?? Feel free to pm if you do not want to publish that data

John ... M-25 is very nice as well. Identical aesthetics, but, as you noted, Class A/B. I think full A to 10 watts, then B all the way to 150 per side. The rebuild on the M-22 was $450 including return shipping. I got it for $500 (a good deal), so have less in it than the guy wants for that M-25. The M-25 would be fun to look at, and, if as advertised, should be e beauty. These amps are far more than lookers - they really do perform. Best quick description I could give is that they are a "musical" Krell, or "Krell with soul".

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