any info,manual about Yamaha B-2 ?

[elviukai]

another one

a

 

[elviukai]

and this one

a

 

[jewilson]

I have a B2 Manaul

In some of my stuff I have the Sony service manual for this amp. Of course Nelson correct it does use Power FET not MOSFET and it has a FET Cascode front end. They was a very high tech amp for the 1970's. SONY also made the very Cool NS1000 speaker with the titanium domes after listening to JBL, Bose, Rectilinear these were a amazing all they needed was some good film cap in the cross over.

I will look for the manual.

 

[elviukai]

oh it would be great! maybe I could fix it then also I need readjust it. without manual its hard..

 

[jewilson]

elviukai,

I still am looking for it. I found several service manuals that I have not seen in over 10 years. So it may take a couple of day and hopefully it not in my addict.

 

[jewilson]

OK I found the manual for the amp after searching my house. what a pain. I have to much stuff.

 

[jewilson]

The outputs are 2SK76 and 2SJ26
http://www.thevintageknob.org/VFET/1975/VFET75.html

The manual is about 20 pages I recomend that purchase one at the place I found below. I can scan in a few pages but not the whole thing.

You can purchase a B2 manual at . http://www.treasurechestcorp.com/(iyczco455il0ez55myun3x55)/results.aspx?type=SM&brand=133&model=B2

Both Sony and Yamaha made power FET or VFET
http://www.thevintageknob.org/VFET/VFETselector.html

Claim to have the 2SK76 not the 2SJ26
http://www.tiptopelectronics.com/pdfs/industrial/semis_original.pdf

Regards

 

[elviukai]

yes

very thanks for You, You wrilly helped me a lot. I beg that my both V-fets are down is 2sk 76 I had no time to check properly this amp..

i wonder about what value this amp have in modern world? fixed and unfixed? I quaes arround 150-180usd broken and 250-400usd working?

also if this is is not a big problem I need schematic (not whole manual) to calibrate bias and read voltages.. if its not very many pages Could you scan it?

 

[jewilson]

I don't think it would be worth much even working on ebay.

Here is the inputs predriver and drivers board. the bias voltage is 13.3 volts. The would make changing to MOSFET very difficult.

I'll up load more later got to go.

 

[SkyChu]

FYR!

TR101: 2SA872A
TR102, 103: 2SC1775A
TR104, 105: 2SK43
TR106: 2SC1439 B or V
TR107, TR108: 2SA810 B or V
TR109: 2SA810 B or V
TR110: 2SC1452 B or V
TR111: 2SA872 BV
TR112: 2SC734 O or Y
TR113: 2SA561 O or Y
TR114: 2SC1775 BV
TR115: 2SC1775A
TR116: 2SA872A
TR117: ?
TR118: ?
TR119: ?
TR120: ?
TR121: 2SC1452 B or V
TR122: 2SA810
TR123: 2SC1452
TR124: 2SA810

OUTPUT : 2SK76 X 2 & 2SJ26 X 2

 

[jewilson]

B2 AMP for sale on EBAY

http://cgi.ebay.com/ws/eBayISAPI.dl...8599159&rd=1&ssPageName=WDVW#ebayphotohosting

elviukai, since you like this amp so much the another one for sale on ebay. you could use your for parts.

 

[gpdavis2]

He can't. Because I bought it (it didn't sell at $350 so I got it on the relist). And it is every bit as wonderful sounding as elviukai thinks it is. I have been A/B listening to it and my much newer bipolar output stage Yamaha MX-1000 and the B2 is clearly a better sounding amp. As a result I am selling my MX-1000. Guess I'll keep my fingers crossed about finding parts.

I called TipToe electronics listed above and they don't have any parts. I will continue my search and if I find any V-FETs, as soon as I get a dozen of each side for myself I will let everyone know where they are available.

BTW, I have the full B2 schematic in electronic format. Send me your e-mail address and I'll send it along as a JPeg.

The B2 has a truly magic sound to my ears. Needs better speaker binding posts, though (didn't everything in '77-'79?). I'll be replacing mine in a few weeks (time - where does it all go?).

Happy Listening!!

 

[elviukai]

yamaha

yap, great amp. it has very good midrange indeed,verry. comparing with pass labs aleph 5 with quality parts it is not looser.. maybe bass only a litle bit thin.. and hights to sharp, comparing with pass product or tube amps.. but comparing to any other new comercial designsin 200-600usd range he is a killer yes i would like to have schematic. i found one person who sugest me spare parts - sk 76.

 

[anatech]

Hi gpdavis2,
May I have a copy of the schematic? bhome.at.sympatico.ca. Replace the .at. with @

Thankyou ! -Chris

 

[jewilson]

gpdavis2,

It's a good sound amp considering when it was designed. Of course it could use a bigger power supply.

You might be able to find the N channels FET's but the P's look to be a different story. I have the power supply from one of these amp in and old preamp I designed. Anyway, the page I left of the shematic is all you need. I have the rest but it's a hassle to scan then it reduced to the correct size for the board.

Happy listening
Jim

 

[jewilson]

The meter circuitry is more complex than the amp.

 

[gpdavis2]

If you want a copy of the schematic, send me a pm with your e-mail address. However, I tried to send to elviukai and it bounced because the file size is 2.39meg in JPeg format. I have used Photoshop to reduce the maximum amount possible by that route. Photoshop can't get it any smaller. Has anyone got any better ideas on how to shrink or zip? I'm happy to send around, but need to get it into a smaller size.

 

[gpdavis2]

The meter circuitry is more complex than the amp.

Almost true. Lots going on in the meter circuitry. I've never looked at one from McIntosh or Sony or whomever, but this is certainly very busy.

 

[anatech]

Trade mark

That's Yamaha's trade mark. They take a design, then impossibly complicate one section. It's as if one engineer just has to show off. The meters on this one, the muting circuit on another or protection ...
Of course, that's where the most problems are typically. And have a lamp just light? Never, they have to be part of muting or the power supply.
-Chris

 

[gpdavis2]

Believe you are right. The speed sensors on their KX-1000 cassette deck is some sort or weird 'light-pipe' and when the reflections are off the deck won't run correctly. Very complicated.