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 ...
Fortunately, the huge 33,000 mF output caps tested as new ...
Trafos were in perfect condition
Nameplate is a bit banged up, but do you see one on today's gear?