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

Yep. With the phones on, blood pumping in my ears is significantly louder than any noise floor. I really can't tell if the amp is on or off as it's sitting out of sight, have even left it powered up overnight a couple of times accidentally.

Adapter is just a DIY thing with a Neutrik XLR and some random bit of wire wrapped around the terminals. Screen is connected to the XLR shell and to the M-22 ground terminal at the other end. I tried disconnecting the M-22 end, did not make any difference. I use it with the stock Audeze balanced cable.

The tests above were done with the Pavane on (but not playing anything), or in standby. If I disconnect the M-22 inputs, there is lots of hiss, so try a different set of interconnects in case they have a bad joint.

Also, I'm using SYS which is passive so cannot generate much noise by itself. You might get different results with an active pre.

 

I found a Mitsubishi da-a10dc for $100 on Craigslist. Great deal, right? I'm thinking about checking it out.

 

Thanks, good to know that it's possible to get a black background with the M-22. I wonder why @foo_me was getting audible noise? Lots of variables in the chain, I suppose.

 

I have not used my M-22 with headphones....I suppose I could try. When I had the M-22 gone over it had some distortion and static on one channel caused by a corroded relay. Once cleaned, the distortion and static were gone. The person doing the work, Scott Frankland, was quite impressed with the extremely low noise.

Maybe @foo_me has a similar problem with his M-22.

 

Give it a shot, let us know how you get on? I can send you a banana plug to female xlr adapter if you need it?

 

Sure. Yes, please send me the banana plug/XLR adapter so I can try it. I'll PM you my address. I have stock HD650 headphones with a 4-pin XLR cable.

 

Well I have been keeping an eye out for an M22 myself but may have found myself the owner of a pair of other Japanese 1980's power amplifiers



picking them up tonight

..dB

 

Very brief audition but sound VERY promising . @Marvey you would love this guys house , horn stack, compression driver's lined up the stairwell. He has been a collector for 40 years, mostly altec, jbl, electro voice. Sadly clearing out his collection to cover medical bills .

Looking forward to playing with these a little more. He compared them to spectral gear (which he owns too)

..dB

 

I would love that too. All that old altec and jbl stuff is so interesting. So many different creations...

 

I hope this is the right topic for my question. I’ve got a Pioneer M-25 recently, but having trouble finding replacement caps for the 100V 470uf and the 80v 100uf axial caps. Can I use bigger values or can I use radial caps and bend the leads? That would be the easiest.


Edit:

Today I finally I’ve finished restoring the M-25.
It was my 3rd diy project so I’ve messed up a few things, and resourcing some caps was troublesome.
Thanks to @JK47 for helping me to identify a few parts.

I made some notes to not to replace the variable resistors responsible for the current control, but totally forgot about it and replaced them.
It made the right side sight of the amp much hotter than the left and I had no means to adjust it.
I had to buy dummy loads and it took me a few weeks to find someone who would lend me an oscilloscope, a sound generator and an AC meter to adjust it as per the service manual. But now it works and no more heat problems.

I’m listening with the small Dali Zensor1 speakers for now but I will have a few bigger speakers on loan later this month.
few pics:
https://imgur.com/a/BJFTE

 

One for sale for 1.1k on Rochester craigslist. Looks to be in nice condition. @ButtUglyJeff Looking for one of these? Its nearby...
https://rochester.craigslist.org/ele/d/pioneer-22-class-amp-series/6395363909.html

 

Not at $1100. I blame the @Marvey effect...

Its actually reassuring to see it was used consistently.

 

We should try to get the Chinese to clone it.

 

Corners would be cut, lesser components and transformers would likely be used.

I got my M-22 for $800 pretty recently, so more reasonable deals can be had. I'm not sure why people are picky about paying around a grand, as this is still a world class amp that beats most other amps at multiple times the price. The days of picking it up for $400 are probably gone, unless you happen to live in Japan.

 

Even if you did pick it up for $400, it would cost another $600 to restore. I don't want to pay $1100 unless it's already all sorted.

 

Not if you restore it yourself, maybe $100 in parts, and it's not a very difficult remove and replace.

 

I agree, I wish I could solder better but I just can't. I should take a class.

 

I’ve finally restored my M-25 and edited my post above.
Its not that hard, and I’ve learned to solder from youtube only a few months ago.
You could practice on some old boards. Definitely worth it on the long run.

 

I was tempted to try it too, the boards look relatively straightforward to work on.

Are you referring to the bias control resistors or something else?