Yamaha B-2 restoration journey

yep, CDE would fit. I have a set here. The ones I have are 18,000 and have 4 pins each. Two of the pins are dummies (just for support), thus the two dedicated pins will handle all the current. These fit just fine. I will be using Panasonics tho. Same pinout, same diameter but slightly taller and 22,000uf. Those fit just as good.
 

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Oh, and about them pins vs lugs and one handling more current or not...here is Nichie's own spec sheet showing that they make the same cap with either terminal, same specs ;)

The problem you have is that you choose a 5 pins cap with 4 active pins and one dummy. Would it make a difference if you use only two of the 4 active pins?? do not know...
If you look at Nichies's spec, they show the thickness of those pins. Different cap, different mfg, but that should give you a ball park idea.
 

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yep, CDE would fit. I have a set here. The ones I have are 18,000 and have 4 pins each. Two of the pins are dummies (just for support), thus the two dedicated pins will handle all the current. These fit just fine. I will be using Panasonics tho. Same pinout, same diameter but slightly taller and 22,000uf. Those fit just as good.
I see, yours are slightly different indeed. Not sure which pin is what (except 1), but your best option would to use 2 and 4 (if possible polarity wise). You can't use 1 and 3, because you need them off-centered.

I was forced to use 1 and 4 due to the pin-out on mines, that's why I have the small fitment problems.

CDE.jpg
 
Btw, if your pin-out is like this (1 and 3 active, I don't think you can use them in the B-2, because they need to be off centered.

No I remember, that's why I chose 5 pins, to get the pins off centered ;)

CDE1.PNG
 
If I were to use these CDEs, I could only use the center pins (1 and 3). The sides (4 and 2) are dummies, support only, not connected to anything. I could actually use them as support and drill couple of extra holes in the board.
These are 40mm caps so they would fit either way, center or off-center. The ones you have are 50mm, it looks like and they have 4 active pins... You could not just drill through the board and use those for support, and you must follow the off-center pattern of the original caps.
 
If I were to use these CDEs, I could only use the center pins (1 and 3). The sides (4 and 2) are dummies, support only, not connected to anything. I could actually use them as support and drill couple of extra holes in the board.
These are 40mm caps so they would fit either way, center or off-center. The ones you have are 50mm, it looks like and they have 4 active pins... You could not just drill through the board and use those for support, and you must follow the off-center pattern of the original caps.

Yes that's true.. And there will be no drilling holes in PCB's :eek:
 
The shinier cap sleeves are supposed to make the high's sound a little cleaner and more polished. I went for the matt sleeves; they're supposed to add a little more to the mid range. ;)

Doesn't mapleshade carry audiophile grade heat shrink? I wonder if it works on film and not just electrolytics?
 
OK, the CDE's are in and they fit very nice after all. Also mounted some 2.2 uF films for bypass.

Some communication with a CDE engineer made me proceed with the initial plan. Great customer service btw, I was instantly emailing with an engineer instead of a helpdesk. He said there were absolutely no technical drawbacks while using only one - and one + pin of these cans. He said the pins are interconnected on the inside and the pins can easily handle 10A of continuous current flows.

I gave the two cans on the right some extra support (foam) underneath them and I made an extra brace with sturdy foam on the inside of the black metal bracket (whichs holds the cans) which fills the space between the metal bracket and the top of the cans. These cans aren't going anywhere.

I bent the pins of the cans in a way that they make full and flat contact directly to the solder pads. Also, the pins of the bypass caps are directly in contact with the bare solder pads. Very happy with the results.

Because I consider myself as inexperienced, my next steps will be: reinstall the power board, the heat sinks + VFET's and the driver boards (in old state). When everything works properly, I will proceed with next phases:

1. Redo driver boards and test.
2. Redo meter board and test.
3. LED upgrade.
4. Mount and connect new binding posts + new speaker wire.
5. Mount new RCA sockets and (most likely) rewire for direct input in the driver boards and bypass all buttons and pots.
6. Put everything back together.

I hope to finish this within 4 weeks.

Some pics of today's work:

IMG_3125.JPG IMG_3129.JPG IMG_3124.JPG
 
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really nice job, those CDEs will do great!

you may want to add a drain resister in parallel to each of those caps since you are planning on going "in and out" of that amp...
 
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really nice job, those CDEs will do great!

you may want to add a drain resister in parallel to each of those caps since you are planning on going "in and out" of that amp...
Thanks, I'll think about that. I thought they are discharged after 3 hours or so?
 
Yesterday I forgot C251 and C252 on the sub PSU board. I did them today, along with re-soldering all wires ans cleaned everything.

IMG_3168.JPG

Later today I went ahead with the new binding posts and speaker wires. I bought some professional gold plated terminals from CMC. I had some Van den Hul Snowtrack speaker cable lying around and thought that I could use that in the B-2. Maybe it's a bit over done, but I like it. I actually use the same wire as actual speaker wire between amp and speakers.

For the binding posts I made a plastic (not sure what the real english name of the material is) plate which comes at the place of the original speaker terminals. After some measuring and drawing I drilled 8 holes of 9.5 mm. The binding posts are 8 mm, but then I had some room to get them aligned. I chose to mount the positive terminals all the way up in the hole and the negative all the way down in order to gain full strength of the metal back plate.

I crimped 8 mm gold plated rings directly on the bare wires with a small amount of solder for strength. The gold plated rings are directly mounted on the binding posts for maximum conductivity.

The plastic plate mounted with painting tape in order to draw on it:

IMG_3172.JPG IMG_3171.JPG

IMG_3174.JPG

Make sure to start with a small wood drill (2 mm), after that in small steps to 9.5 mm with metal drills:

IMG_3175.JPG

The final result of the plate after sanding:

IMG_3176.JPG

The Van den Hul Snowtrack wires with the rings mounted:

IMG_3181.JPG

Mounted on the binding posts:

IMG_3185.JPG

End result:

IMG_3189.JPG

IMG_3191.JPG

I already test fitted the power board. No problems with the thicker wires.

Next up: the Triac switch, because one connection of my power switch has broken off.

I already have the parts and the schematic, but I'm not really sure how to wire with those two transformers. I'll have a look into that.
 
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For the triac power switch as in this post Is your unoptainium power switch worth $5 and an hour or so of your time?, the "LOAD" is the two transformer in parallel.

Because you have to keep the individual fuse for each transformers, connect MT1 to the brown wires that go to the fuses (you may have to run new brown wires depending on the location of your triac). Assuming that the mains' incoming phase is connected to MT2, then connect the grey wires of both transformers to the mains' neutral .

Simple :)
 
I'm thinking about using Panasonic polyester 10uF caps for my 22,000 uF caps bypass.

Now these could be mounted right at the big capacitor board bypassing each CAP individually as Mr. Yamaha did, or I could mount 2 on each of the VFET boards themselves, bypassing +85/ground and -85/ground at each VFET board. Thoughts?
 
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I'm thinking about using Panasonic polyester 10uF caps for my 22,000 uF caps bypass.

Now these could be mounted right at the big capacitor board bypassing each CAP individually as Mr. Yamaha did, or I could mount 2 on each of the VFET boards themselves, bypassing +85/ground and -85/ground at each VFET board. Thoughts?

First reply would why these bypass caps are needed.....

Following several reference books on power amps (Bob Cordell, Douglas Self), the caps are merely to account for resonance frequency cancellation of the big reservoir caps beyond the 500 kHz region, and less for RFI/EMI HF decoupling as often mentioned. As such 1uf to 2.2 uF is often more than appropriate, and you can keep using polypropylene capacitors as Mr Yamaha did. Polyester caps are not distortion free, and starting with a distortion source at the very beginning of the power supply chain....

Secondly, the whole resonance topic of the large reservoir caps in the higher kHz region is sensitive (worsened) by inductive elements, and as such soldering them as close as possible to the pins of the reservoir caps is key.
Soldering those caps on the VFET boards is adding a lot of inductance in the 'system' due to the wiring and PCB track between reservoir caps and the bypass caps..... not good, potentially making things worse than not having them at all.

As for HF decoupling, on the contrary.... decouple as close as possible where needed, i.e. on the VFET boards themselves, using SMALL value bypass caps in the order of 47nf to 100nF (max, like for the +/-B2 rails on the driver board); or else you may start coupling instead of decoupling.....

So it's a dual job to do.

PS: the B+/B- power rails on the VFET boards continue to the driver boards via de connecting PCB below the heatsink, and have no further HF decoupling on the driver boards (which is a shame), so adding those 47~100nF bypass caps on the VFET board incoming power rails (to E) is no luxury at all in the era of wireless communication.
 
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