Yamaha MX-35

dino74

Active Member
I'm using two MX-35s to Bi-amp the Linn Tukans in my bedroom. I also have an extra 35, so I decide to recap it.

I got a paper copy of the MX-35 SM and made some PDFs from them. The design seems to be the same as the M-35 but I think these PDFs are better quality.

http://akdatabase.com/AKview/albums/userpics/10007/Yamaha MX-35 Schematic.pdf
http://akdatabase.com/AKview/albums/userpics/10007/Yamaha MX-35 Service Manual.pdf

I'm trying to figure out if these are the correct Nichicon capacitors to use.
ES for C103
KZ for 107, 119
PW for 123,121

Screenshot from 2019-01-10 18-40-32.png
 
The C103/104 are easy, signal path coupling/DC-blockers. Personally I would use Wima MKS2 film caps there but if not then for sure ES BP.
https://www.mouser.de/ProductDetail...=sGAEpiMZZMv1cc3ydrPrF7l45uRd9dVhvGS3cHOkNOA=

C121/122 and C123/124 look like de-coupling caps (or/and local filtering?) on the supply lines for the STK's? (+V=9 & 10, -V=6 & 7?) if so then the PW look like a good choice.

C107/108, C119/120, I'm not experienced enough to call their functions (de-coupling in filters & anti-distortion feedback loops?) but would think that KZ would work fine there. I'd up that 100µF/6.3v to 10v or 16v.

Wish that I could be more helpful, perhaps Avionic or mbz etc will drop by and have better thoughts.

Cheers,
James
 
Brat, thanks for your input. I'll take your word and try out the Wima MKS2 .

Seems like there are two type of caps in this box. Rubycon CEW for coupling and unknown marked AU for decoupling.
IMG_0498.jpeg

Since I only use this in 2 channel mode and not four, I'm going to swap out the push terminals for plug terminals
IMG_0501.jpeg IMG_0503.jpeg
 
That little triangle thingy on the dark blue cap means that it is a Matsushita aka Panasonic.

I tend to really like Panasonic FC and FM caps. 105° temp rating, low ESR, relatively high ripple rating compared to other caps with the same capacity and long life. The FC is a good all rounder and the FM have even lower ESR and longer hour rating but less selection for capacity. Iirc they tend to be less expensive than Nichicon also.

After reading a lot of posts by ConradH and other people that I've learned to respect I've come around to replacing all small capacity electrolytic caps with Wima MKS2 or Panasonic film caps unless they won't fit or it gets too expensive. The 10µF MKS2 are a bit large and won't fit everywhere as well as being fairly expensive so I tend to use them only where it really counts (like signal path) but pretty much everything 6.8µF and smaller gets film caps.

Nice binding posts. :thumbsup: I like those type a lot and use them pretty much everywhere (speakers also).

Cheers,
James
 
I went with the FMs where I could and will use the MKS for the signal path. Thanks for the input Brat!

$30 of parts for a $20 amp o_O
 
I went with the FMs where I could and will use the MKS for the signal path. Thanks for the input Brat!

$30 of parts for a $20 amp o_O

Happy to be of use.

Yeah, I kinda did the same thing with my AX-300. I think that it only cost me something like €15 and I probably spent double that upgrading it. But it's pretty well built for a simple little 30w amp and sounds sweet with a pair of Canton GL 260 speakers.

Cheers,
James
 
Almost made a dumb mistake. I decided to bump up the main caps to the next size but didn't see if it would fit but luckily it clears the lid by a couple of millimeters.
IMG_0508.jpeg
 
Almost made a dumb mistake. I decided to bump up the main caps to the next size but didn't see if it would fit but luckily it clears the lid by a couple of millimeters.
View attachment 1390052

Well, it looks like you got that one nailed. :D

But in any case, a couple of mm is as good as a km as long as it fits. I can't quite see in the photo, what caps did you use there?

Cheers,
James
 
For future reference: United Chemicon KMH come in a 5-pin config. (You have to cross reference the data sheet & P/N's, there are several different pin configs.) The 5th pin can be snipped off and the rest slightly bent in towards the center and then they are a drop-in fit.

I haven't used Cornell Dubilier yet but Avionic says good things about them so I assume that they are of good quality. I'll have to make a note about that pin config for my own future reference.

Cheers,
James

ps: I'm dying to know. What were the nails for?
 
Thanks James! Thanks a good to know about the 5 pin. LOL at the nails. I made the speakers terminals at my parent's house using my dad's table saw to cut the plastic mounting plate. I also need some nails to hang various junk in the garage so I grabbed a bunch from his nails can and put them in the amp.
 
Argh! I was all done except for the speaker terminals. One was a bit tight and tried to push the wire down to bend it and broke the pad. Oh well, good lesson to learn on an inexpensive amp rather than one of the others.

IMG_0545.jpeg
 
Well, if it makes you feel any better, I did something similar with my CX-1. After soldering one of the big 2.2µF film caps that I installed in the -20db amp section I bumped it. And the thick leads overpowered one of the traces and broke loose. And that one is the right signal path. I had to use some 0.8mm wire to jumper the traces.

When you buy the bifocals you might as well buy a set of reading glasses also. I found that while the bifocals were great for general use when I'm working at the bench or reading I got a crick in my neck from tipping my head back to use the lower lens over an extended time.

Cheers,
James
 
Hopefully I get sometime in the next couple of weeks to scrap off a patch and solder the wire directly.

At my last appointment, the doctor also recommend getting a reading only set.
 
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