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

Here I'll recap your M-22.. *deep voice* Last time.. on pioneer m-22 the series.

 

I need Yggdrasil (and some smaller gear) to sell in order to fund this. However the first 30 seconds was enough to convince me that my amp is not a total dud, will definitely be worthwhile getting it reconditioned. I would guess in your case the bias adjustment was what made the difference but who knows.

Really surprised that Freya in passive mode would sound different to Saga or SYS, resistors is resistors... maybe something else is going on. I'm a bit old-school / skeptical about cables and other crazy stuff. Was pleasantly surprised to notice that my new Van Damme interconnects are 'silver plated OFC' (£40 for 1.5m pair with XLRs is roughly an order of magnitude less than "audiophool grade")

 

It was this https://www.head-case.org/forums/topic/8505-major-surgery-revives-35-year-old-amp/ that really got me interested in the M22, actually.

Incidentally, my "200 hours only" unit died within 24 hours of me receiving it. Its quite likely that any unit (even the minty fresh looking ones) will need a lot of reconditioning to perform at its best.

 

That's the same thread that got me started too!
Agile_One had heard my SET amp for the k1000 at a meet and was looking for something for his K1000s and found the M22s.
When my amp broke down and I was looking for a replacement, I saw his impressions and went down the same road and here we are.
It's cool that others are finding this gem and enjoying it.
It's nice to get something that offers such a great sound at a reasonable price relative to the current gear being made now.

 

Btw, like the Mitsubishi, there are other vintage amps out there that provides comparable value as the M22.
Just picked up Accuphase C200/P300 that sounds just as good and was again a good price.
I would find something though that can be readily re-capped/reconditioned.

 

My Freya had a turntable, CD player, and a Gungnir Multibit plugged into it, not to mention every output going somewhere as well. I'm sure the power supply of the Freya vs the non-powered passive Sys played a role as well, especially when using my turntable (signal is hyper sensitive to changes and interference). The Sys is so basic and has almost no outside influence to signal passing through, where as the Freya has a crap ton off stuff going on plus a tube stage in a slim chassis. In my case simplicity won the day, and no I wont be buying a Saga.

I'll forego the convenience of a volume remote control in my quest for the most direct, clean, and unadulterated signal.

I should also mention I set the DC offset and current bias of both the Mitsubishi and Pioneer amps before listening yesterday. Both were a little out of spec with the DC offset, but the current bias was pretty close to bang on the money for both of them.

 

Most of us have been lucky with M-22 units that sound good from the get go, and will sound excellent with light refurbishment. I've also read accounts of others receiving heavily used / badly stored units that seriously under perform, that probably need a lot more work. Mine sounded so good after biasing (before the damn protection circuit kicked in) that it's hard to imagine it being better, so I'm excited to see what a good tech can do. Mine is going to Scott Frankland for repair next week. He had this to say:

"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."

Winders mentioned that he talked to Scott about Cardas RCA input upgrades and installing a power socket instead of the fixed stock cable. I asked about this, and thought he was honest with the assesment:

"The RCA jacks are not that bad, so replacing them with higher quality jacks will give only a subtle improvement. Same goes for the line cord. In a class A amp, the line cord does not drop voltage when the power increases as it does in a class AB amp, so increasing the wire gauge buys you nothing. On the other hand, there are better quality line cords available. But again, I think the improvement will be subtle."

The one recommended upgrade I will definitely consider:

"The biggest improvement will come from replacing the small filter caps bypassing the early amplifier stages (input, pre-driver, etc.). Higher quality caps in these positions will sharpen up the resolution without trading off musicality. Bypassing the main filter caps with smaller, faster caps is also recommended."

 

Main filter caps = the gigantic caps that give the M-22 its distinctive look?

Also, has anyone had issues with the bias and DC offset changing (by something like 50 mV and 20 mV, respectively) when the amp is flipped? I had to account for that difference when biasing my unit.

 

I doubt he's referring to the big 33000uf caps on top, replacing those would be weird.

 

• Fix lame-ass soldering work: check
• 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 check. $400 + $370 EMS from Japan + import taxes. The amp was "maintained" 2 months ago, according to Hifido.

Summary: this amp is kinda freaking amazing!

Now the not-so-good:

• The treble and clarity are really a bit much for me, especially at higher volumes. EQ and/or careful system matching probably needed. Not recommended for stock HD800
• Bass and maybe overall tonal balance is a bit off. Sub-bass extension seems good, but I think mid to upper bass is a bit sucked out. Maybe. I can't put my finger on exactly what is wrong here.
• It still sounds like solid state, just really good solid state (I'm not that familiar with tube gear, big pinch of salt needed).

... and it should not come as a surprise to anyone that those huge heatsinks get far too hot to touch.
Probably this will benefit from re-capping etc in the long run.

Only first impressions based on quick listen to short reference playlist and reasonable familiarity with my other gear. Will try switching back and forth with the Phonitor for comparison, maybe next week.
Full chain: Pavane > XLR > Phonitor (hp out) > Garage1217 20dB att. > SE > M-22 > LCD-XC

PS: thanks @Marvey !

 

That chain ... why lol.

Edit: You need a Schiit Sys, don't you.

 

Anything short of a Saga is costing you transparency @bengo , DO IT!

 

Guys, guys .. I have the Sys already. But I was curious how it would sound with the Phonitor crossfeed. The other thing is just a resistor or two.

 

You just need to upgrade to the Phonitor 2 which lets you loop the crossfeed matrix through the preamp outputs

 

Anyone in Canada. http://www.canuckaudiomart.com/deta...-exclusive-m5-monoblock-power-amplifier-pair/

The granddaddy of the series. Will need a decent transformer to convert the line ac.

..dB

 

Check out his other listings as well, a treasure trove of Pioneer gear, including some turntables. I think this is the same guy that sold a pair of mint M-22's recently and an M-25...

 

It's perhaps pointless, but figured I'd throw this up. It's a short clip I filmed at a friend's house with my M-22 in the chain. He's playing Dreams by Fleetwood Mac on vinyl. The room was low light, but you can just about make out the M-22 next to his 300b SET amp. This doesn't begin to do justice to how good it sounded because of the crappy iPhone microphone, but may give someone who's on the fence about buying one a small sense of it's dynamics and sweet tone.



The chain was a vintage JVC turntable w/ AT-ART9 cart > Avid Pulsus phono stage > Van Alstine tube preamp > M-22 > vintage Yamaha NS1000 speakers.

 

How did the M-22 sound compared to your friend's amp(s)?

 

I posted a short description of the amp shootout on page 5 of this thread. I ultimately preferred the clarity and punch of M-22, but the 300b amp was no slouch. You could easily tell which was SS and which was tube, both displaying classic attributes of each.