Yamaha B-3, no longer Sansui exclusive.

[GrisPato]

After reading several threads about the Yamaha V-fet amplifiers I decided to get some myself.
Always an exclusively Sansui man, I can still appreciate the efforts of other manufacturers in the late '70s.
So this week two Yamaha B-3s arrived from Japan.
And they did not disappoint!
Great build quality, big transformer, big filter caps, copper, all heatsink on the sides and ofcourse the V-Fet's.
Of that last thing you're never sure buying on Yahoo Auction Japan.
I can never resist opening the equipment, so some pictures of the insides and outside.




















I will restore them this winter. Hopefully with some advice from the V-Fet experts.
I am already enjoying them.

 

[JimEGR]

Can't go wrong with all of that luscious solid copper in there!

 

[bolero]

Ha, I was going to ask what's up with pots on the front & back?? But I see they are linked.

Congratulations!

 

[bolero]

The Vintage Knob details are very positive. And funny

http://www.thevintageknob.org/yamaha-B-3.html

 

[Mike244]

Congratulations!!!!! I couldn't resist the temptation of vfet either

 

[rottalpha]

Congratulations!!!!! I couldn't resist the temptation of vfet either
View attachment 3353110

TA-5650 or TAN-5550 vfets

 

[rottalpha]

Ha, I was going to ask what's up with pots on the front & back?? But I see they are linked.

Congratulations!

It is a single set of pots linked to front and back

 

[Mike244]

TA-5650 or TAN-5550 vfets

5650 waiting in line for recovery

 

[GrisPato]

To get the correct size of the filter capacitors I disassembled some more.



64 X 102 mm.
Replacement wil be Epcos B41560A/B41456B 33,000uF-63V 64,5/51,6 X 106,7 or Kemet ALS40A 66 X 107 same capacity.

 

[Sparkplug]

To get the correct size of the filter capacitors I disassembled some more.



64 X 102 mm.
Replacement wil be Epcos B41560A/B41456B 33,000uF-63V 64,5/51,6 X 106,7 or Kemet ALS40A 66 X 107 same capacity.

What is wrong with these? Have you measured them?

 

[GrisPato]

Sadly they measure high ESR (120-150 mOhm) and low in capacitance, around 22000uF.

 

[Sparkplug]

Sadly they measure high ESR (120-150 mOhm) and low in capacitance, around 22000uF.

Hmmm … must be the weather, I’ve never ever pulled a bad cap out of any equipment here in Japan. They always measure right on. Good luck!

 

[GrisPato]

For me it is just the third one that measures so low in capacitance % but is the ESR that especially does it for me. Never had it this high with late '70s equipment. ( Not that I have done so many).

 

[Sparkplug]

For me it is just the third one that measures so low in capacitance % but is the ESR that especially does it for me. Never had it this high with late '70s equipment. ( Not that I have done so many).

LOL, when they got to go, they got to go … they just look so cool.