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

Ah, gotcha.

That's less exciting than the prospect of the M-22 being way more powerful than we initially thought, lol.

I thought we were still on the topic of amp power (Kurtz's post previous to rshuck's).

 

Sorry, yes, the M-22 & Nissyo 1500 pull 190W from the wall, measured on a Belkin Wemo smart switch. @spwath explains what I meant more clearly. This was in case anyone was trying to spec a step down transformer.

 

M-22 is actually a 40+ watt class A into 8 ohms amp. Unless mains fluctuate a lot; sine into dummy resistive load should do around 44 W without leaving class A operation. That translates about 95..100 W idle consumption per channel.
Speakers rarely are flat 8 ohms. It's nice to see the amp being conservatively spec'ed.

M-22 should consume about 200 W and a 1500 VA transformer consumes at least a few watts idle, doing 200 W loading, maybe 10 W losses in the step up transformer. That means I'd look into what the bias on your amp is,
it might be on the low side.

Also, the step up transformer better be beefy, otherwise I'd expect the bass to be limp-dick. Forget 200..300VA units for power amplifiers, despite on paper appearing to be powerful enough.
Any extra transformer between power socket and amp means extra losses and reduced psu load regulation capability.
A large one like the 1500 VA has less of that effect.

 

After warmed up for a little while (2 or so hours) it settled in at 197W from the wall. I also can’t verify the accuracy of the Wemo switch - I’d assume it was better as a rough estimate.

 

There's one for sale on CAM that just went up. Looks like he'll ship stateside for $120CAD. That's reasonable for such a heavy amplifier. I'm not sure if the price is reasonable either, but at least its cheaper for you americans because of the exchange rate.

https://www.canuckaudiomart.com/det...22-amp-amp-c21-preamp-in-very-nice-condition/

edit. lol at the shipping cost to new zealand/australia

 

Do not buy from mookauto; he’s a scam artist. Lies about condition, etc.

 

He had one posted previously as well (and an M25 as well I think) and I had asked about the last service etc for it. He could not answer so I didn't proceed. I'm getting the sense he is buying these from overseas (maybe he travels there regularly, or has family) and then bringing them back here to Canada to sell for a profit, with the internal condition being completely unknown. Buyer beware.

 

Exactly. I did buy an M22 from him because I decided I was willing to take the risk. It was a 100v Japanese version. He claimed it had been serviced and modified for 117V use, but couldn't expand on how. Upon receipt, not only could I not find any such modification, it also had blown fuses and blown capacitors. Just as well, since I overhauled it myself -- but he's not being honest.

 

Yeah it looks like he's been selling vintage Pioneer stuff from Japan since late last year. I hope you gave him a red/negative rating on CAM.

 

Anyone had experience with M-22's bigger brother, the M-25?

Curious if it retains the 22's magic while (being AB) not getting super hot?

My 22 is off-duty during SoCal's summer months.

Also open to recommendations of any other great sounding vintage amps (late 70s / early 80s) that run cool and cost under $3k?

 

@skem I agree with @rlow , people need to know about this kind of shady shit.

 

@skem So sorry that happened. Interesting that so many Quebecers are involved in the drama on the CAM fraudsters thread. Not trying to discriminate or anything but... Quebecois are a funny lot... they even have their own version of cam who's name escapes me, and their own little hifi ecosystem that is completely separated from the rest of the hifi world. I got into it, briefly, when I purchased my Cadenza loudspeaker system from Arteluthe. Thankfully Robert Gaboury isn't a fraud.

 

Thanks for the sympathies. I haven't left him bad feedback because I couldn't (easily) find out how! Anyway, amp has received the royal treatment, which I'll write up as soon as I'm done tweaking... Looking for an audio analyzer at the moment for final adjustments.

 

I have the M-25 and it gets very hot within 30 minutes. I’ve never had the M-22 but I can’t imagine that it can be much hotter.

 

My M25 runs cooler than M22, but still noticeable after 3-40 mins. IME M25 doesnt really have the same magic as M22 does, and despite its higher rated wattage, struggles driving power-hungry speakers (sub 86dB).
I recommend the Quad 606, runs way cooler and more powerful. I much prefer the Quad to the M25 driving Harbeth P3ESR and Kef 105.2. YMMV tho.

 

Flying back to Thailand from UK and the first thing I'm doing is looking at a Pioneer M-25 and a Sansui AU-9900. The Pioneer needs some aesthetic work, black case work etc. The latter amp is almost mint. Both same price, around £400.
And need to buy that pesky extra transformer if I purchase M-25.. has anyone tried those remote control sockets with hifi gear?

 

OK, decided on Pioneer, they are just iconic designs really
I found a guy in Cambodia who buys vintage gear from japan in bulk, inc 4 of these amps, around $400 each. Will drive over the border with Thailand in 2 weeks to see him. Fingers crossed

 

Hello guys. I'm new here. I am in the process to buy a M-22 but after reading some posts here, I am less sure. I was a potential buyer from Mookauto who had sales problems with some peoples here. Please, when you buy something and you have the chance to give a transaction feedback, don't hesitate to do it. It is easy and will help the community here. As it is near my town, I will look at the two amps he wants to sell. About the 100V transformers used in these amplifiers, as the V+ and V- for supply is only + 28 and -28 volts DC. This means that using 120 VAC will raise the V+ and V- at +33 and - 33 Vdc. This is not really high and I don't think it should hurt this amp. To correct this situation, I would only lower a bit the output transistors bias. As there's many regulators in the amp, other voltages will stay as they are now.
I have to decide if I buy or not Mookauto amp. If I do it, Ill go directly there to see what I'm buying. Thanks

 

I have been contemplating this exact issue. You’re right that the input and VAS stages are regulated by zener diodes. They might just need higher wattage resistors at most. You’ll be creeping up on the filter cap voltage ratings in the power supply, still under them but with thermal de-rating you are potentially using up their life quite fast. The extra voltage on the output stage might be fine or easily compensated.

FWIW, mine blew a fuse when connected to 120V. I don’t know why. I haven’t tried again since re-capping it.

Also, the lamp is probably not rated for the extra voltage. You can just disconnect or increase the dropping resistor R35. Disconnecting it has the advantage of removing a wirewound radiator that contributes lightly to the noise floor.

you saw this, I presume: https://www.superbestaudiofriends.o...r-m22-as-a-head-amp-and-recapping-guide.6717/

 

Thanks a lot Skem for these informations. Did you replace the 4 big power supply caps ? If yes, What did you buy ?. I have to decide if I go to Mookauto house to see this amp. Near 5 hours of driving time. I asked him some picts and other informations and he's not very cooperative. Also if it is $1100 CAN for a non working amp, that's too pricey. I also have a Forte 1A to refurbish but it is not sexy as this Pioneer.