• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

EW mods for Yamaha B-2

H

hugomac

New Member
Looking for info regarding Re-capping my B-2 also C-2x if it needs it, which brand Nichicon or Blackgate also which Caps. I have the service manual & Schematic. Getting a Yamaha Technician whose been working on yamaha Amps & cant wait to work on a B-2. im in melbourne Australia so i unfortunately cant get Echowars to do it but can get his help. You there EW? If i can do it as per your specs would really appreciate it.

Hugo
 
Register to hide this ad
I hope your tech has experience handling VFET repairs.

Blackgates, though sometimes available from boutique shops, are no longer manufactured and will be mega expensive. I know EW is partial to Panasonic, but Nichicon or Elna would have been used and is my preference.

I can speak to Nichicon and have a couple general recommendations.

Power circuits - PM/PW or HE series. 105* long life
Critical audio path - KZ if size is available, then work your way down the foodchain - KW/FG and KT also where 105* is appropriate and the others are not available.
KG super tune for larger filter caps when size and fit is available, otherwise Pansonic THA or if you really want to go big some cornell dubilier screw terminal caps.

I'll let everyone else that's used them comment on Elna's. If I were recapping my MX-2000, I would stick to what Yamaha used where there are Elna's.
 
Last edited:
Good Luck with your venture Hugo.

The only other person in Australia(that I'm aware of) who has both B-2 and C2x is Aussie AKer timofred.

I sold him my B-2 and C2x. :yes:

Neither have been EW modded. :no:
 
i used ELNA Silmic II's for my A-1's power supply (except for the big Panasonic cans). i like what i'm hearing. they're only 85 degree rated, but the A-1 doesn't get very hot (although my transformers seem to get warmer after the recap).
 
The B-2 is 100% DC coupled throughout, with the exception of the back-to-back electrolytics on the little input board at the rear panel, and these can be bypassed using the 'Normal/Direct' switch, also on the back panel. But I'd still replace them.

My capacitor selection process is approximated here. As far as everything else on the B-2, its lifeline is the +/-80V regulated supplies, which supply the pinchoff voltage that keeps the VFET's from committing suicide. Anything and everything should be done to see that this supply is as reliable as possible, which means replacing the stock zeners (D205 and D206, 30V 1W zeners), and ALL the 2SC458 transistors, which are scattered throughout the amp (the meter circuitry has a bunch of them). I usually replace D203 and D204 with a series-pair of 1N4148's for reliability's sake.

The four large power supply caps are problematic. Nichicon sells a KG Gold in a 15,000µf and 22,000µf that will fit (the 22,000µf requires some rethinking of the power wiring at the rear, but it can be done).
 
EchoWars said:
The B-2 is 100% DC coupled throughout, with the exception of the back-to-back electrolytics on the little input board at the rear panel, and these can be bypassed using the 'Normal/Direct' switch, also on the back panel. But I'd still replace them.

My capacitor selection process is approximated here. As far as everything else on the B-2, its lifeline is the +/-80V regulated supplies, which supply the pinchoff voltage that keeps the VFET's from committing suicide. Anything and everything should be done to see that this supply is as reliable as possible, which means replacing the stock zeners (D205 and D206, 30V 1W zeners), and ALL the 2SC458 transistors, which are scattered throughout the amp (the meter circuitry has a bunch of them). I usually replace D203 and D204 with a series-pair of 1N4148's for reliability's sake.

The four large power supply caps are problematic. Nichicon sells a KG Gold in a 15,000µf and 22,000µf that will fit (the 22,000µf requires some rethinking of the power wiring at the rear, but it can be done).
Click to expand...

Sage advice as always. If the input caps are coupling caps, could they just be replaced with quality polypro caps?
 
No room. The caps are sandwiched between the tiny PC board and the back panel. I'd put some decent quality electrolytics in there, and use the 'Direct' switch position if their presence is an issue for you.
 
EW passed this tread onto my yamaha tech, we need to know which power supply caps to get. I've looked at Digikeys website (very helpful). He says that really the Power Supply ones are the most important & thinks he can get all the rest with his connections with Nichicon but is not sure about PS Caps. He also said that modern ones would be alot smaller. Would we still get Electrolyitics?

Thanks so much guys for the support, just got the C-2x & were blown away at the condition its like brand new especially inside. Supposedly it hasn't been used much. That wouldn't need Re-Cap would it? Can't wait for the results. Once i get this done all i have to do is re-wire the NS-1000's & get my beloved PX-2 going.

Hugo
 
hugomac said:
EW passed this tread onto my yamaha tech, we need to know which power supply caps to get. I've looked at Digikeys website (very helpful). He says that really the Power Supply ones are the most important & thinks he can get all the rest with his connections with Nichicon but is not sure about PS Caps. He also said that modern ones would be alot smaller. Would we still get Electrolyitics?

Thanks so much guys for the support, just got the C-2x & were blown away at the condition its like brand new especially inside. Supposedly it hasn't been used much. That wouldn't need Re-Cap would it? Can't wait for the results. Once i get this done all i have to do is re-wire the NS-1000's & get my beloved PX-2 going.

Hugo
Click to expand...

I also forgot that AKer timofred(who bought my B-2 and C2x)has had an extended loan of my PX-2.There wouldn't be too many people in Australia with that combination of gear...:no:
 
IIRC, the stock power supply caps (18,000µf 63V) are 50mm diameter, but 80mm in length. The diameter must stay the same, so the terminals will fit in the board. I have used the Nichicon KG Gold 22,000µf 63V caps several times (from Michael Percy Audio, or Parts Connexion). They are 100mm in length, which means that some of the primary AC wiring at the rear of the amp had to be re-routed to make room for the longer cap, but I can assure you that it can be done.

If you're talking about the small electrolytic caps (sorry, your post is not clear on this), then please read the link I provided in Post #5. Panasonic FC and FM, Nichicon PW and HE, and Panasonic SU for bipolars. All at Digikey.
 
You must log in or register to reply here.
Back
Top Bottom