YAMAHA B-3 on the way...to me!

Discussion in 'Yamaha' started by Cosmin2000, Oct 16, 2017.

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  1. Cosmin2000

    Cosmin2000 Active Member

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    Unlike the older brothers, i.e. B-1 and B-2, B-3 was only sold in Japanese domestic market. You'll never see one on 220V or 120V.
     
    Last edited: Oct 17, 2017
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  2. Cosmin2000

    Cosmin2000 Active Member

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    They look somehow similar, but I guess they are very different. BX-1 monoblocks are the only Yamaha amps made in pure class A, using bipolar transistors, whereas B-3 is runing in AB class and is based on V-FETs 2SK76A/2SJ26A, similar to those in B-2.
     
  3. clinic-audio

    clinic-audio all on YAMAHA untill 1990

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    Here it is

    Yamaha-B3-schéma.JPG
     
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  4. rottalpha

    rottalpha Yamaholic

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    Thanks Cosmin :)
    but you think we would already known that. Both Mark and I have BX-1s.
    The comments were aimed solely at physical appearance....albeit BX-1 is class A, J-fet input stage; BJT output stage, but it is essentially two 50W bridged design, to achieve the 100W mono. That is where the similarities end.
     
    Last edited: Oct 17, 2017
  5. Vint Age

    Vint Age B-1 With Yamaha

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    Thanks!
     
  6. clinic-audio

    clinic-audio all on YAMAHA untill 1990

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    Hello

    but you think we would already known that. Both Mark and I have BX-1s

    me too (4) !
     
  7. Oilmaster

    Oilmaster Ozzy Subscriber

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    You really have to take care to get a true 100V supply to your B-3, not a 110~120V.
    A lot of consumer transformers offered are 220V->110V, and thus with 230~240V mains ending up with 115~120V output.
    No-go zone!

    Myself, I weekly scan the local websites for used industrial transformers, as I can't have enough of them.
    I found a couple like the one below, which come out of Japanese machinery exported to Europe, and thus provided with a step-down transformer.
    As you can see, it allows for multiple mains voltages in steps of 10V, not a luxury with nearly 240V mains voltage in Holland, and around 230V in France
    Note that the actual mains voltage in your house depends on the entire distribution in the neighborhood->street->building->your apartment.

    IMG_0908.JPG

    IMG_0909.JPG

    The unit above is a 1500VA baby, around 20kg.
    I guess you may be able to find similar transformers on Taobao

    Second option is to buy the decent stuff (true 230V to 100V) new.
    Around 750VA should be more than enough for the B-3 (even two of them).

    If you have Schuko type wall sockets, then this is a very decent product:
    https://airlinktransformers.com/product/japan-europe-voltage-converter-eu-ja0750

    If you have UK type wall sockets, then this one:
    https://airlinktransformers.com/product/japan-uk-voltage-converter-uk-ja0750

    The above units are so-called "auto-transformers". Nothing wrong with them, I use one in my main system (1500VA though) and it does not impact the sound at all compared against the big baby isolation transformers in the photo above. If you do insist on using a true isolation transformer, the same company sells those as well as loose items:
    https://airlinktransformers.com/cat...ange?input_voltage=230&output_voltage=100&va=
     
    Last edited: Oct 18, 2017
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  8. Vint Age

    Vint Age B-1 With Yamaha

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    To my thinking the B-3 is a very nice piece indeed ... but with that said it's too high maintenance outside of Japan even with its BTL mode and especially since I already have plenty of Yamaha V-FET goodness. :)
     
  9. rottalpha

    rottalpha Yamaholic

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    I had countless opportunities to acquire one or a pair for that matter. For some reason I passed and now I am in a buying "freeze".
    I will eventually get a pair some day, if for nothing else, just to complete the 1,2,3 set ;)

    I cannot wait for Cosmin to receive his and post some listing impressions

    or for Oilmaster to rebuild one of his then post his findings...that would be really interesting
     
  10. Cosmin2000

    Cosmin2000 Active Member

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    I am also very curious to see and discover this beautiful model. Today I will receive the B-3 (the package is on the way to my location, transiting Wuhan city).
    I have bought also a step-down transformer (actually is an auto-transformer like pointed by Oilmaster before) 1500VA, 220-100V from Delixi Chinese transformer company. It has a display where one can see the output voltage at any moment.
    I think is more than enough to power properly the B-3 which has a stated consumption of 190W.
    By the way, anyone knows if these 190W are at full power?
     
    Last edited: Oct 18, 2017
  11. Cosmin2000

    Cosmin2000 Active Member

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    I know that you have and enjoy the B-2 power amp. I would have bought thus one, I am really intrigued by B-2 sinergy with NS-1000Ms. I found one in Romania, partially recapped, but the cost was more than two B-3s.
    However, Yamaha sold B-3 and B-2 with the same price: 200000 Japanese Yen. This must say something about the quality of the former, despite the fact that is a "lesser" power amp...
     
  12. Oilmaster

    Oilmaster Ozzy Subscriber

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    Good you got a decent 100V stepdown transformer :thumbsup:
    1500VA allows you to buy much more 100V stuff :D

    190W is at full power with pure 1kHz sinewave input;
    In idle and normal operation, it's more like 25~50W.

    Yes.... I am about to start marathon rebuilt of my units around January, and notably another unit for another AKer from California, who is waiting desperately for more VFETs
     
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  13. Cosmin2000

    Cosmin2000 Active Member

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    Dear friends,

    My B-3 finally arrived, after a long struggle with the courier company. Actually, the step down transformer came in my possession first, it has a voltage variable between 96V to 108 V. Most of the time is close to 100V AC.
    I have not powered yet the B-3. I have opened and examined this amplifier. All I can say is just they don't do it like this anymore.
    The B-3 seems like a product carved from pure aluminum block, impressive build outside as well as inside. I never saw a better construction in an amplifier!

    In comparison with my Trio L-05M monoblock amps, the Yamaha B-3 comes from another galaxy. And, mind you, those monoblocks are well build, if not impressive by todays standards.

    The V-FETs are original Yamaha 2SK76A and 2SJ26A (thank God!), no sign of any replaced component. It has some very small blemishes usually undetectable with the naked eye (you need to put some intense light to observe these) and one small hit in the left side heatsink, lower part. Looks like 8.6 out of 10.
    Should I power the B-3 or do more investigations?

    IMG_20171023_190218.jpg
    IMG_20171023_190203.jpg
    IMG_20171023_185037.jpg
    IMG_20171023_183731.jpg
    IMG_20171023_185751.jpg
     
    Last edited: Oct 23, 2017
  14. Cosmin2000

    Cosmin2000 Active Member

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  15. Oilmaster

    Oilmaster Ozzy Subscriber

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    nice photos ! thanks.

    One thing with your tube pre-amp: I hope you are sure it has an output coupling cap, because the B-3 can be set to "direct" coupling, i.e. without a coupling cap.
    Hence, if you are not sure what your high-voltage tube pre-amp has, I would certainly keep the input switch set to "AC" (which means capacitor-coupled), and NEVER switch the pre-amp on after the B-3 !
    It may cost your dearly !
     
  16. Cosmin2000

    Cosmin2000 Active Member

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    Greetings, Oilmaster! That is not a tube preamp, is a tube amp (it has the output transformers). I do not intend to use it in any way connected with the B-3.
    Sadly, here I do not have a preamp, I will pilot the B-3 from my laptop audio board as preamp. I know this is not what it supposed to be, but this is the situation for the moment...Back in Romania I plan to pilot the B-3 with Trio L-07CII. You said once they make a good pair...
    By the way, when you listen to your B-3 what volume level you choose from the front/back potentiometers? DC or AC coupling?
    Last question: do you have any ideea about V-FETs power supply voltage?
    Because the main filtering capacitors (which are huge!) are 27000 microF/63V, I suspect that V-FETs supply is less than 63V for 100V AC mains voltage. Am I right?
     
  17. Oilmaster

    Oilmaster Ozzy Subscriber

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    The B-3 and L-07CII are a very nice match. When driving some APM-77,and sourced by a Sony CDP-R3, it's pure sonic nirvana :)

    DSC09303.jpg

    Ah, those dual volume pots per channel, opposite interacting... made me confused at first, and still makes no sense to me why one at the back and one on the front... Anyway, I've put both at no attenuation at all. That's why mankind has invented pre-amps after all...I think... And as such the standard quality carbon pots have the least sonic influence on the signal.

    For the moment I run the B-3 on AC input because the L-07CII desperately needs a recap, now having a naughty DC offset on one channel, tripping the B-3 into protection if connected in DC. Still..... it sounds great :confused:

    The power rails to the VFETs are at ~42.5V . Say 45V max with 7% mains increase. Hence, 63V rated buffer caps are the thing to go for. 50V would also be ok, but leaves little margin and shorter lifespan.

    EDIT: it is probably not required to replace those extra large PSU caps; they are most often still in excellent shape. But as I mentioned before, the amp needed months of daily playing to start sounding well. Bigger caps means longer reforming time.
     
    Last edited: Oct 23, 2017
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  18. SoCal Sam

    SoCal Sam Lunatic Member

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    Keep computer audio cards and personal players away from impossible to find VFET's. Get a proper DAC with a proper analog output stage to play your digital files.
     
  19. rottalpha

    rottalpha Yamaholic

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    love the setup, really nice pad Oilmaster!
     
  20. Cosmin2000

    Cosmin2000 Active Member

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    You have a wonderful system, Oilmaster!
    I wonder how it stands the B-3 against that Sony Esprit power amp. Which one sounds better to your ears?

    As far as the main filtering caps I have no intention to change them or any other component in the near future. The caps size really amazed me when I had opened the B-3. If they are filtering 45V then they will still be good in 10 years or more as well...

    Today I powered and listened the B-3. Even if the test speakers are nowhere near Yamaha NS-1000M, I could clearly hear new sounds on many recordings. I would say the sound has some richness, is warm, detailed and holographic.
     

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