Yamaha B-2

April
1 9 7 6 april 1976
1 9 8 0 1980

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 !"

Yamaha B-2, image 1 Yamaha B-2, image 2 Yamaha B-2, image 3
Yamaha B-2 specifications
Title Value
POWER section POWER section
Output : 2x 140W (20Hz...20Khz, 4 Ohm)
2x 100W (20Hz...20Khz, 8 Ohm)
Frequency response : 0Hz...100Khz (+0 / -1dB)
10Hz...100Khz (+0 / -1dB)
Bandwidth : 5Hz...100Khz (-3dB, THD 0,5%, 8 Ohm)
Phase rotation : +0...-30° (10W, 0Hz...100Khz)
THD : less than 0,08% (rated power, 8 Ohm)
less than 0,01% (50W, 8 Ohm)
less than 0,008% (10W, 8 Ohm)
IM : less than 0,03% (50W, 4 Ohm & 8 Ohm)
Damping factor : 70 (8 Ohm / 20Hz)
70 (8 Ohm / 1Khz)
50 (8 Ohm / 20Khz)
S/N ratio : 110dB
Residual noise : 0,25mV
S/N ratio : 115dB (IHF-A, input short-circuited 4,7kOhm)
Input : 775mV / 25kOhm
METERS section METERS section
Display range : -50dB...+5dB
(0dB = 8 Ohm or 0dB = 0dBm)
(= 0,01W...300W for an 8Ohm load)
Accuracy : +5 to -20dB : ±1dB
-20 to -40dB : ±2dB
-40 to -50dB : ±3dB
Frequency response : 20Hz...20Khz : ±1dB
Rise / decay time : 100µs / 1s.
GENERAL GENERAL
Componentry : 8 V-FETs
4 FETs
95 bipolar transistors
2 ICs
66 diodes
Dimensions : 43,6 x 15,1 x 37cm
Weight : 26kg.
Yamaha B-2 : 1 topic
(last updated topic shows up first)
  • My first YAMAHA                             (11)last updated by theophile - 30/07/2010, 11H49
page online since : 2005
page updated : march 2010
page type : LGT / KNB
page weight : 152.05 Kb / 0 b

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