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Yamaha MX-1 Thread

Hi Jaka,

I did not replace C1~C4 in my amp. And I still have not found replacements that will fit well in the available space. The main problem is the rather short height of the case.

Those Kemet caps are probably too tall (82mm), you would have to measure very carefully to see if there is enough space under the top cover. They are also only 36mm in diameter, so they will not be secured in the mounting clamps. Lastly, they are screw terminal caps and the Nichicons have a large solder tab. The screw terminals can be adapted, but that needs space, back to the first problem.

C15 and C16 were not populated in my amp, so I did not look into finding replacements. Considering that they are in the soft-start sub-power supply I would probably use some Panasonic FC if I needed to.

Which caps went back order at Mouser?

Cheers,
James
 
Hello.
Caps that went to back order are: C13 (Wima MKS2 505MKS2-2.2/63/10A 2.2µF/63v), C18, C19 (United Chemi-Con KYB 1000µF/100v) and Relay RY101, RY102 and Variable Resistor VR201, VR202. Lead time on those are more than 20 weeks.

Best.
Jaka
 
RE: Backorder.

I've seen the US United ChemiCon distribution facility and it wasn't pretty. They're having to fly in large qty of product for critical parts.

FWIW, I've also been in the US HQ @Kemet.
 
Bratwurst7s said:
OK, I'm posting a zip of the cap buy sheet here, and will edit a note into the first post that it is here.

The caps shown in the sheet are what I used in my amp with one exception, that being C39. I used a United Chemicon KYB there. A Nichicon LKG would be a better fit in the space available and that is what is entered in the sheet.
As always, there are a lot of different opinions concerning cap choices. I used what I prefer, and they worked very well. But there are many other possible choices out there. Also, Mouser availability is very spotty at the moment, with long lead times on some out of stock items.

Cheers,
James
Click to expand...

I think the time has come. - I hope Avionic reads this one too lol

Thanks a lot for your file with all the caps and you have replaced on it. My MX-1 is still running fine, though I am starting to feel it is really time to put some attention to it. I've been using it almost daily for the past 3 yrs, and it's pushing 25Yrs old now. However, after the pandemic stock sort of sucks in many regards. I hope this won't be much of an issue.

What I am really interested in right now is to ensure the most future proof restoration possible. I know that when a part has to go, it might just happen. But, besides sound, is there anything else other than reflowing the soldering points, looking for heat stress, and recapping the unit? Wondering if:
  • Is it worth replacing heat paste on the transistors and heat sinks?

  • Is it worth stacking up on spare transistors to have in case down the road?

  • What’s a reputable seller we can get these from?

  • I imagine we should look for alternatives to Toshiba originals, correct?
I will contact the company that can send a board made to upgrade speaker lugs with - I’ll mention you sent the measurements just in case. Thanks a bunch.
https://speaker-terminal.com/en/.
Also, will definitely order the circuit relay, fortunately available in North America
40.61.9.012.0000 Finder, Power Relay, SPDT, 12 VDC (newark.com)

Finally:
There is a part that currently is unobtanium and it seems to go when something else goes wrong, required for the HCA circuitry. The BA3122N concerns me and I wonder if keeping two of those at least handy sounds like a good idea? See links below - What do you guys think on these?

Yamaha BA3122N IC Custom Rohm SMD PCB - MX1 MX2 AX730 AX930 - XG609A00 WOW! | eBay

https://www.diyaudio.com/community/...amplification-hca-circuit.152734/post-7024354

The reason why I want to go to this length with this amplifier, is simply because I want to keep it until I am dead, or try as much as I can. I am not joking. See, this is what happened. Rant coming. I landed on the Yamaha as a sort of “in the meantime” amplifier.

I have had several other amplifiers around here. Not that they sounded worse or anything. To each their own. Say I had some McIntosh and some Aragon, and while some could have enjoyed their sound more, I preferred the sound of the Yamaha myself. It does it for me, and I know I am only using 30 Watts of its power, tops. So, that being said, I cannot think of the hoops I would have to go through to get back to something that sounds like this Yamaha. I am sold on it and I want to get it to last another few decades more. Fun enough, I would have to upkeep another two amps from the ‘95-’00. Both are also Japanese. I do not know why, but it seems I like the sound of that decade or something! These three I hope they come along for a long haul. And do not hate me for being polygamous here lol - Accuphase A-20 (Who knows what could I do to even consider servicing this ever, suggestions?) and Sansui a907MR (another one I'll be getting the list done to future proof before is too late)

Thank you guys for the attention and looking forward to reading back regarding any extra mile possible to ensure longevity of this unit to the max.

PD: To be honest, I have even considered the idea of drilling the top case or having one done that can accommodate main filter caps through lol! Impossible to get one sthat fit that form factor. - Ending up with a Yamaha MX-1 “Targa” edition cannot be so bad, right? Right??. Aside from the fact that shipping the unit would be a PITA, in which case I would be looking at Snap On caps to jank them out during moving, lol.
 

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Bastian said:
I think the time has come. - I hope Avionic reads this one too lol

Thanks a lot for your file with all the caps and you have replaced on it. My MX-1 is still running fine, though I am starting to feel it is really time to put some attention to it. I've been using it almost daily for the past 3 yrs, and it's pushing 25Yrs old now. However, after the pandemic stock sort of sucks in many regards. I hope this won't be much of an issue.

What I am really interested in right now is to ensure the most future proof restoration possible. I know that when a part has to go, it might just happen. But, besides sound, is there anything else other than reflowing the soldering points, looking for heat stress, and recapping the unit? Wondering if:
  • Is it worth replacing heat paste on the transistors and heat sinks?

  • Is it worth stacking up on spare transistors to have in case down the road?

  • What’s a reputable seller we can get these from?

  • I imagine we should look for alternatives to Toshiba originals, correct?
I will contact the company that can send a board made to upgrade speaker lugs with - I’ll mention you sent the measurements just in case. Thanks a bunch.
https://speaker-terminal.com/en/.
Also, will definitely order the circuit relay, fortunately available in North America
40.61.9.012.0000 Finder, Power Relay, SPDT, 12 VDC (newark.com)

Finally:
There is a part that currently is unobtanium and it seems to go when something else goes wrong, required for the HCA circuitry. The BA3122N concerns me and I wonder if keeping two of those at least handy sounds like a good idea? See links below - What do you guys think on these?

Yamaha BA3122N IC Custom Rohm SMD PCB - MX1 MX2 AX730 AX930 - XG609A00 WOW! | eBay

https://www.diyaudio.com/community/...amplification-hca-circuit.152734/post-7024354

The reason why I want to go to this length with this amplifier, is simply because I want to keep it until I am dead, or try as much as I can. I am not joking. See, this is what happened. Rant coming. I landed on the Yamaha as a sort of “in the meantime” amplifier.

I have had several other amplifiers around here. Not that they sounded worse or anything. To each their own. Say I had some McIntosh and some Aragon, and while some could have enjoyed their sound more, I preferred the sound of the Yamaha myself. It does it for me, and I know I am only using 30 Watts of its power, tops. So, that being said, I cannot think of the hoops I would have to go through to get back to something that sounds like this Yamaha. I am sold on it and I want to get it to last another few decades more. Fun enough, I would have to upkeep another two amps from the ‘95-’00. Both are also Japanese. I do not know why, but it seems I like the sound of that decade or something! These three I hope they come along for a long haul. And do not hate me for being polygamous here lol - Accuphase A-20 (Who knows what could I do to even consider servicing this ever, suggestions?) and Sansui a907MR (another one I'll be getting the list done to future proof before is too late)

Thank you guys for the attention and looking forward to reading back regarding any extra mile possible to ensure longevity of this unit to the max.

PD: To be honest, I have even considered the idea of drilling the top case or having one done that can accommodate main filter caps through lol! Impossible to get one sthat fit that form factor. - Ending up with a Yamaha MX-1 “Targa” edition cannot be so bad, right? Right??. Aside from the fact that shipping the unit would be a PITA, in which case I would be looking at Snap On caps to jank them out during moving, lol.
Click to expand...
I intend to hold on to my two pairs of MX-1 I have here, have other amps but none that sound so melodious with my NS1000Ms as the MX-1
 
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