Yamaha B2 - the "why" and the "how" of a comprehensive rebuild
- Thread starter rottalpha
- Start date
-
- Tags
- v-fet yamaha b-2
Hi! I am the fortunate / recent buyer of the B2 amp shown in the video posted earlier bench testing the amp for harmonic distortion. There was a comment about the quality of sound, so I thought I would chime in. When I first hooked up the amp I was blown away by the sound! The clarity in the upper midrange and highs are phenomenal. Cymbals were crystal clear (as I have never heard)! The sensitivity and detail are probably due to the incredibly low noise floor on this amp. With the gain turned all the up, the amp is dead silent (even when hooked up to my 99 SdBL sensitive Altec horn speakers. I could hear the texture of the snare drum like never before. On harmonics of string instruments, I heard and felt vibrations that gave me "goose bumps". Also, vocals were detailed (with texture) and I could hear the subtle breathing of the singer on songs that I had listened to for years, but had never heard before! The human voice is the most familiar "instrument" to us all, and this amp is almost "human" in the way it sings to me! As expected, the sound stage of both instruments and vocals were heard in "3D" and well localized.
I do not make these comments lightly as I have had many amplifiers including tubes (SE 300B, 2A3, and PP EL34, 6550) during my "journey" over the last 45 years. This B2 has that sweet "tube" sound of Yamaha V-FETs but is somehow stronger in the low / mid bass with much faster / articulate highs than any tube.
The bass is also very tight and controlled. I have been a Sony V-Fet fan for many years, but I must say that this B2 restored by Peter, is better sounding than my Sony V-FET amps including my TAN-8550 and TAN-5550, with more control / precision in the mid and lower ranges of instruments. I may no longer need a subwoofer with this amp as it drives my Altec Magnificents (16 ohm) and Altec 604's to new levels of excellence (tight bass with punch) that has put a smile on my face.
I tried the B2 amp first through a pre-amplifier and then through input 2 using the direct gain controls to adjust the volume on each speaker. Both modes sounded outstanding!
My wife (who is not an audiophile) was in the room when the B2 amp was playing and I noticed that her head turned to listen to the music. I later asked her if she liked the sound of the amp and she replied with a firm "Yes, it sounds like real music!"
Peter is one of the most passionate and knowledgeable restorers of VFET amplifiers that I have had the pleasure to know. As you can see in his three part post on Yamaha B2 restorations, he is simply remarkable in the amount of care, evident when he selects each component used to rebuild / restore his amps. He builds each and every amp as if it were to be his own. If you want a "life changing" amplifier look no further. My amp is a bargain at twice the price! Do not miss an opportunity to own one of Peter's amps! I assure you that the sound and restoration quality will exceed your expectations!
Peter, thank you for this wonderful Yamaha B2 amplifier! I cannot imagine it getting any better!
I do not make these comments lightly as I have had many amplifiers including tubes (SE 300B, 2A3, and PP EL34, 6550) during my "journey" over the last 45 years. This B2 has that sweet "tube" sound of Yamaha V-FETs but is somehow stronger in the low / mid bass with much faster / articulate highs than any tube.
The bass is also very tight and controlled. I have been a Sony V-Fet fan for many years, but I must say that this B2 restored by Peter, is better sounding than my Sony V-FET amps including my TAN-8550 and TAN-5550, with more control / precision in the mid and lower ranges of instruments. I may no longer need a subwoofer with this amp as it drives my Altec Magnificents (16 ohm) and Altec 604's to new levels of excellence (tight bass with punch) that has put a smile on my face.
I tried the B2 amp first through a pre-amplifier and then through input 2 using the direct gain controls to adjust the volume on each speaker. Both modes sounded outstanding!
My wife (who is not an audiophile) was in the room when the B2 amp was playing and I noticed that her head turned to listen to the music. I later asked her if she liked the sound of the amp and she replied with a firm "Yes, it sounds like real music!"
Peter is one of the most passionate and knowledgeable restorers of VFET amplifiers that I have had the pleasure to know. As you can see in his three part post on Yamaha B2 restorations, he is simply remarkable in the amount of care, evident when he selects each component used to rebuild / restore his amps. He builds each and every amp as if it were to be his own. If you want a "life changing" amplifier look no further. My amp is a bargain at twice the price! Do not miss an opportunity to own one of Peter's amps! I assure you that the sound and restoration quality will exceed your expectations!
Peter, thank you for this wonderful Yamaha B2 amplifier! I cannot imagine it getting any better!
Welcome to AK and the wonderful world of the B-2.
Nice write-up and agreed that it truly is an amazing amplifier; I'm sure that what's Pete is doing to them ensures many many more years of incredible performance!
zaibatsu
yam
Buying a high quality build there too, no disrespect to Yamaha but no mass manufacturing from any company could afford to hand build amplifiers the way some here do.
Not to mention the improvements that have been made possible with time. Very fine original pieces, but even finer now.
Not to mention the improvements that have been made possible with time. Very fine original pieces, but even finer now.
Hello Andrew and welcome to the forum. Thank you for your kind words and for sharing your B-2 listening impressions!
I have to say that I never heard the B-2 with a set of very high efficiency speakers or with a 16ohms load, and I hope one day I would be able to. It is always helpful to hear different listening impressions when the B-2 is mated to different components than we have in our own systems.
It is also very rewarding to me to see the B-2 getting the recognition that it deserves and to be able to bring back to life one unit at the time. Some of the AK members here are doing the same thing, so this forum is a good base of shared-knowledge for v-fet amps aficionados from across the globe.
About the Sony v-fet amps: when time permits, we have to do something about them too so they don't fall behind
Pete, what are those purple capacitors you are using for C107, 108, 109?
like he said^^^^^^
I used them because I have a bunch, but silver mica in not necessary there. New ceramic is OK or leave the original in.
Cool Cause silver micas are expensive from reputable sources.
You can find lots on eBay but not sure how good they are. I have a couple hundred 100pf's from there and have used them so far with no issues but still.....
I am very slow at reading minds^^^ ?
please do spell out what you are thinking about??
I am very slow at reading minds
please do spell out what you are thinking about??
I was responding to Nick , he seems to have removed his post . I should have quoted him, but I think he said , now paraphrasing here, that ceramics may not be the right cap. SO I was hoping he would clarify that .
Athanasios
Boards ready to go into an old B2 that was previously my parts unit!
For this rebuild, I am following all the teachings of this thread. Input JFETs on the driver boards are the Toshiba SMD BL rank, equivalents Pete suggested from the Yamaha B3.
This is getting close. Selector boards are installed in B2, meter board has been recapped, and now all is left is to start wiring it up and test.
For this rebuild, I am following all the teachings of this thread. Input JFETs on the driver boards are the Toshiba SMD BL rank, equivalents Pete suggested from the Yamaha B3.
This is getting close. Selector boards are installed in B2, meter board has been recapped, and now all is left is to start wiring it up and test.
Last edited:
the original are ceramics and worked for ~50 years. You can replace with better caps if you want.
The ones that are more critical are the original styrene caps.
very nice!
Sorry about that! I was responding to:
Yes indeed, the schematic shows C107, 108, and 109 are 6pF, 3pF and 5pF caps respectively and are polystyrene precision caps. If you're going to replace them with ceramic caps they need to be NP0 or C0G types. Same value Silver Mica caps will also work.
Last edited:
Thanks, they look like ceramic to me but I could be wrong. Nonetheless, I have not found any that needed replacement.
I just replaced them all and those were originally ceramic in my unit (at least the package looks like ceramic to me!).
The polystyrene are:
C101 = 47 picofarads
C104 = 100 picofarads
C106 = 330 picofarads
I switched those for Wima polypropylene. The original polystyrene were fine, so I kept them. I just like polypropylene caps because they are pretty.
Ah yes, you're right. C107, 108, and 109 are C0G Ceramic types; my point was more that they need to be tight tolerance caps and like Pete, I've always found the originals to be fine.