M-4 output transistors

nerdorama

AK member
Subscriber
Are output transistors available anywhere for the M-4? Some web searching didn't turn up much and I'm afraid of transistors from Asia on the auction site.

Thanks,
John
 
Thanks. My searches didn't find this one. I guess I'd still be a little wary as they don't mention a brand but the price isn't too high.

I know several folks here on AK have restored these amps before. I'd like to hear from any of them about where/how they got proper replacements or if there are suitable modern subs.

Best,
John
 
10-4 and thanks. I use Mouser quite a bit, but wasn't sure about substitute p/n's. I would assume that an M-4 is worth fixing if the acquisition cost isn't too high for one needing repair.

They don't seem to command a high price at auction, so I'd want to have some idea that it's an amp with sound quality potential before tackling the project. AK folks seem to think well of them.

Best,
John
 
I would assume that an M-4 is worth fixing
Hell yes..Advertised 120 WPC -- Typically measure around 155+WPC @ 1khz - 8 ohm load before clipping.
 
I've built (4) M-4 amps now, but friends and family keep talking me out of them. I have two more on the shelf and one of those I'm going to build to keep.

Sleeper amps. Solid chassis. Easy to work on. Respond well to upgrades. Very reliable. Slightly warmer than the signature Yamaha sound.
 
If any of you were going to repair an M-4 with a blown channel, is it right to assume you would replace the outputs in both channels? Or leave the good one alone? I'm trying to decide whether I should buy one with at least one channel out. It looks to be about $25/channel for output transistors and who knows what else including caps. I can imagine a $100 parts bill pretty quickly.

Thanks,
John
 
If any of you were going to repair an M-4 with a blown channel, is it right to assume you would replace the outputs in both channels? Or leave the good one alone? I'm trying to decide whether I should buy one with at least one channel out. It looks to be about $25/channel for output transistors and who knows what else including caps. I can imagine a $100 parts bill pretty quickly.

Thanks,
John

Seems like we are looking at the same amp on CL? Certainly a good chassis based on the pictures. I have two other M-4 amps that need a few things and i was also thinking of picking this up and hopefully be able to make one good amp out of all of them.
 
If any of you were going to repair an M-4 with a blown channel, is it right to assume you would replace the outputs in both channels? Or leave the good one alone? I'm trying to decide whether I should buy one with at least one channel out. It looks to be about $25/channel for output transistors and who knows what else including caps. I can imagine a $100 parts bill pretty quickly.

Thanks,
John

Leave the good channel alone.
 
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