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

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

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  1. Vint Age

    Vint Age B-1 With Yamaha

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    Not wanting to thread jack but here's a thought that I haven't explored completely; I wonder if this would work given that the B-3 is so very similar by design? If you're confident that only the V-FET's are dead on the one side and the rest of the circuitry is fine, you could remove the dead ones and then transplant one pair of V-FET's from the working side to the non working side and you'd have a B-1.75 ... :)
     

     

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  2. Cosmin2000

    Cosmin2000 Active Member

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    The Chinese seller from which I have bought the B-3 says he has another B-3, but without the original V-FETS. He modified the amp so now is based on some RCA transistors (IRF...). Are these good replacements?
    Of course, the price is lowered with like 20% comparing with the one I bought. I told him that I am not interested for the moment, because I do not know for sure what other modifications he operated to this unit. What do you think?
    http://r.jwtpp.com/h.DdR6OU?sm=d8a4bb
     
    Last edited: Nov 23, 2017
  3. rottalpha

    rottalpha Yamaholic Subscriber

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    Would you drive a Ferrari with a Chevy engine?
     
  4. Vint Age

    Vint Age B-1 With Yamaha

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    :no: :thumbsdown:
     
  5. clinic-audio

    clinic-audio all on YAMAHA untill 1990

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    Sad news , why don't you refix it ?
     
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  6. Vint Age

    Vint Age B-1 With Yamaha

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    Not everyone has a pocket full of V-FET's. ;) :)
     
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  7. rottalpha

    rottalpha Yamaholic Subscriber

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    Why bother?

    Edit: Scratch that,
    The B-2 is worth repairing. My "why bother" comment was for the modified B-3.
     
    Last edited: Nov 21, 2017
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  8. Cosmin2000

    Cosmin2000 Active Member

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    I am very saddened to inform you guys that my beloved B-3 entered yesterday in protection mode twice. :(
    I also observed a rather unusual rising temperature on hand inspection. After the first protection mode click, it took like 5 seconds and came back to normal operation, then again to protection and afterwards I just stopped the operation of the unit.
    After I came back to Romania, I have listened once the B-3 with no issues, like a two hour session. Now, how can I deal with this?
     
  9. avionic

    avionic " Black Knights " Subscriber

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    Depends which engine..LOL
     
  10. rottalpha

    rottalpha Yamaholic Subscriber

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    This is a unit that is over 30 years old now. There re components such as electrolytic capacitors the are well beyond their useful life in that unit.
    I cannot tell you what to do, but I can predict what it will happen if you do nothing..You will end up with a nice paper weight or door stopper.
    If this was my unit, I would have performed minimum maintenance even before I would have plugged it in the first time.

    If you turn that amp on in its current state, you are playing Russian roulette. You are on borrowed time my friend...

    Take it to someone that understands V-Fets for the maintenance.

    I am sure you will find someone in Romania. Otherwise there are a couple of AKers on your side of the pond that might be able to help ya

    PM me if you would like contacts.
     
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  11. rottalpha

    rottalpha Yamaholic Subscriber

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    True that!
     

     

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  12. Dr. Ear

    Dr. Ear Well-Known Member

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    Did you still use your PC as source? Don‘t do that, as suggested before.
     
  13. Oilmaster

    Oilmaster Drillers go deeper Subscriber

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    It could be that your source has a (intermittent) DC component on it, are you using the c-coupled input connectors or not?
     
  14. rottalpha

    rottalpha Yamaholic Subscriber

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    using that amp as is, without having it serviced is gambling in my book.

    are you planing a B-3 big rebuild anytime soon?
     
  15. Cosmin2000

    Cosmin2000 Active Member

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    The fact is yes, I have used the laptop as my preamp and source, but my setting on the back if the amp was on AC coupling. I shouldn't have done that, I know...

    Although I have a proper preamplifier, Trio L-07CII, and CD Players, I have them stored until I will build my own house.

    The protection engaged after two hours or so.
    Nevertheless, I will not use the B-3 anymore until I'll find a proper technician which knows to work with V-FETs.
     
  16. Oilmaster

    Oilmaster Drillers go deeper Subscriber

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    If the protection comes in that slowly then it is most likely drifting semiconductors by temperature, either circuit diodes and/or transistors.
    That "living heatsink" as I nicknamed it warms up in appr. 2 hours.....so that corresponds to your situation (though not necessarily related).
    I'll be attacking a couple of B-3 units in 2019 or so, by then you're welcome to shuffle in your unit.
     
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  17. rottalpha

    rottalpha Yamaholic Subscriber

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    there is your answer Cosmin. You could not find a better solution to your problem. It sucks to have to wait for a year, but it would suck worse otherwise.

    Yes, an ill faited semi is most likely acting up and giving you a nice warning.
     
  18. rottalpha

    rottalpha Yamaholic Subscriber

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    I might be getting in line myself if I end up with one ...or two B-3's by then :biggrin:

    you should start a waiting list :D
     
  19. Oilmaster

    Oilmaster Drillers go deeper Subscriber

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    Looks like you have negotiated yourself a new shutdown level at headquarters, considering the earlier purchase stop you imposed on yourself :cool:
     
  20. rottalpha

    rottalpha Yamaholic Subscriber

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    lol, is already kinda' late for the self imposed prohibition...given my increasing flock of B-1s.
    Just want to pay respect to the master. I should be able to restore those B-3s if I should ever have them in my possession, but I just think that you would be the person to do a better job than even what I would be able to do for myself :bigok:
     

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