Yamaha B-2

preliminary

The other monster V-FET power-amplifier, coming a year after the original non-complementary B-1, powered by a set of four complemementary pairs of parallel connected 2SK76 & 2SJ26.

Four 18,000µF caps, two enormous trafos, star-shaped heatsinks which many later siblings would inherit from - and unbelievable reliability.

The B-2 quickly became a big bestseller : the total production should be in excess of 10,000 units - quite impressive, for an amplifier priced at 200,000Y in 1976 !
No wonder, it IS one of the best amplifiers of all time : V-FET and Yamaha oblige.

Briefly available in silver in a few markets, late in the production run, circa 1978/1979, but not in Japan.

William, who owns several B-1s and B-2s, has sent this little comment :

"I just did a controlled A-B listening test between the Sony TA-4650, a Yamaha B-2 and a Yamaha B-1.
The B-1 came out on top (at $1600.00 new and being an ALL Fet design, it should have) and the Sony and B-2 were so close. Both use complementary V-fets, so that probably figures. Perhaps the Yamaha units can handle more.
In an Audio Magazine Report, Bascom H. King said that the onset of clipping occured at 220W @ 8 Ohms on the B-1. Thats 46% over spec !"

• My first YAMAHA                             (11)last updated by theophile - 30/07/2010, 11H49 Open this topic in TVK Talk
  • #1
    
    pat66
    08/07/10
    16H29
    Hello,
    
    
    
    I'm glad to fire up this new thread with some pictures of  the inside of my first YAMAHA 
    
    
    
    
    
  • #2
    
    Stoffie
    10/07/10
    11H00
    Nice! And in the background an ESPRIT TA-E901 and an ELCAset deck! You lucky man!
  • #3
    
    pat66
    10/07/10
    11H20
    Hi Stoffie,
    
    Yes you are right for the background 
    
    
    
     Just for compare : the B2 heat sink and the SONY's TA-F7
  • #4
    
    Stoffie
    11/07/10
    12H10
    Yep, Sony units never seem to have big enough heatsinks in comparison.
  • #5
    
    the-real-mandak
    12/07/10
    19H19

    Stoffie wrote:Yep, Sony units never seem to have big enough heatsinks in comparison.

    
    Now that must be why I am hooked on the Yamaha models 
    
    BTW. Pat66, that is a really nice and clean B-2 you got there.
  • #6
    
    roger456
    14/07/10
    12H33
    i also have yamaha B-2, i already re-new all E-CAp inside, the sound was superb, sweet and clear, also have tube taste, nice bass as well, highly recommand you renew this AMP, you will know the B-2 engineer, what they want you listen, what is original sound 
  • #7
    
    Unda Maris
    14/07/10
    17H43
    As I know, the B-2 runs as hot as the hottest Sonys ...  And: Only a hot V-FET amp is a good one ...
  • #8
    
    pat66
    15/07/10
    17H32

    Unda Maris wrote:As I know, the B-2 runs as hot as the hottest Sonys ...  And: Only a hot V-FET amp is a good one ...

    
    Happy to read you again Unda Maris    A V-FET amp must be as hot as tubes are, otherwise it sounds like a ... transistor amp 
  • #9
    
    pat66
    15/07/10
    17H42
    The heat sinks are really big but some other parts are undersized like those "power" resistors on the power supply board.
    
    Too close to the printed board and too weak 
    
    
    
    
  • #10
    
    Unda Maris
    16/07/10
    16H58
    The not-so-smart use of power resistors seem to plague many Yamahas of this time, especially the C-I and B-I. Even the resistors themselves seem to be pretty small for their rating (optimistic supplier) ...
    Sometimes (in order to further disimprove things) they even wrapped a small piece of glass fiber hose around the power resistor, which heats the resistors even more at wire leads (melting the solder joints).
    Pretty stupid from an engineering point of view ... Nevertheless this is not as much "brown engineering" as the notoriously wrong (upside down) mounted power resistors on the Epoxy PCB of the TA-N88 PLPS 
  • #11
    
    theophile
    30/07/10
    11H49
    My first post on TVKv2
    
    I've just returned from visiting my friend who is known at the Audiokarma website as 'timofred'.I sold him both my Yamaha C2x and B-2,plus he has an extended loan of my PX-2.He has them hooked-up to a pair of KEF Cantatas.I almost experienced seller's remorse.The system didn't do dynamics the way that those components did with my Altec Valencias,but it did sound very nice.The record played was the Opus 3 'Depth of Image' test record which I probably know better than any record in my collection.There was a lovely naturalness to the sound,which obviously has to be attributed to all of the components working together,but it was obvious to me that the KEFs were showing the deficiencies of my Altecs to some degree.
    
    
    
    I don't think that I would trade what I have got for that system,but I very much enjoyed listening to that combination of components and it highlighted to me just how capable that eras Yamaha components were.The PX-2,C2x and B-2 work very well together.