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Yamaha B2 - the "why" and the "how" of a comprehensive rebuild

Vint Age said:
Yes indeed! I restored may first B-2 back in 2008 when there was little to no support. We've come a long way since then thanks to your love for this amp and your diligent work so far, not to mention your willingness to share it with others in this thread. You've certainly taken B-2 restoration to a whole new level! :thumbsup:
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And not to mention, in my case all help, tips & tricks from master restorer @Oilmaster and lot's of other AK members providing insights and tips. That's what makes AK a great community :bowdown:
 
If I may add from my painfull experience, It will be very halpfull Peter, if you will elaborate on the prociedurs fo chacking the well functioning of the board, espacialy the driver board. priore to finall asembly.
 
Mr. Yamaha said:
And not to mention, in my case all help, tips & tricks from master restorer @Oilmaster
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Agreed! It's always nice when an EE with a good understanding and a love of analog circuitry gets involved. Not too many do anymore due to the huge focus in the digital domain. I could be wrong but I'll wager that Pete has learned a few things form some conversations with Oscar over the years ... but perhaps that's a subject for a whole other thread. ;)
 
Mr. Yamaha said:
Awesome thread, Pete! Where was this thread in 2016? :D Makes me want to redo or 'finish' my B-2 resto (which is still playing sweet music every day since it was finished).

Reading this thread gave me enough itch to finally start with the restoration of my TA-N7B, which I did this week. Will be a slow project I guess due to the fact of having two little kids :idea:

Keep up the good work! I will follow this thread and may PM you in the foreseeable future about those upgrade boards you developed for the B-2 :rolleyes:

But first the TA-N7B...

Again, awesome work!
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Good to see you are still around Oscar.
Yes, there are a few things you can add to your already restored B-2 to make it more reliable and possibly to get more out of it.

I predict you will enjoy the TA-N7 too. You can go here and see how the TA-N7 wipes the floor with 5 other v-fet amps :biggrin:
 
Mr. Yamaha said:
And not to mention, in my case all help, tips & tricks from master restorer @Oilmaster and lot's of other AK members providing insights and tips. That's what makes AK a great community :bowdown:
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who, that @Oilmaster guy? Neah, he is too busy doing real work, going to other countries and picking up important things for friends....too busy for him to mess around Yamaha forums :biggrin:
 
Vint Age said:
:eek:_O:blah:
The TA-N7 isn't even a real V-FET amp since the V-FET's are in cascode with the BJT's which are doing most of the work.:biggrin:
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yeah, it would take you a while to lift the jaw off the floor and process what just happen once you hear one, then a lot longer to process or care of what the output stage is ;).
 
Arye said:
If I may add from my painfull experience, It will be very halpfull Peter, if you will elaborate on the prociedurs fo chacking the well functioning of the board, espacialy the driver board. priore to finall asembly.
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if your boards are with Patrice, you would likely only have to drop them in and do the bias adjustments. I am thinking that would also come already adjusted too.
One thing to make sure is that the set of vfets you are getting is closely matched set, at the operating parameters / at idle, which in the case of Yamaha B-2 are 58v Vds and ~92mA Ids. Tested for other operating points would also be nice but you need a curve tracer for that.

Unlike Sony who used ranks that span over 2v but relied on a different approach and different design, Yamaha matched their B2 and B3 vfets within 0.05v to 0.3v Vgs. This is not just within the same N or P channel devices but across the P to N channels, so within the entire set of four vfets for either of the left or right channels, you will not find variations of more than ~0.3 Vgs at idle current. This means they had tons of vfets to chose from, which is something we do not.
 
Vint Age said:
That being said, I'll take it that your B-2's sit idle most of the time then? :)
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nope, and neither do the other vfet amps. They take turns and every time I hear one that I did not hear for a while, I get enthusiastic abut it just as the first time.


The problem for me when it comes to the B-2s is that every time I restore one, it end up making its way to someone else. That is a good and a bad thing. Good because the vfet love is shared, Bad because the "shoemaker ends up with no shoes".
 
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vintagejapan said:
View attachment 2777026 View attachment 2777028 View attachment 2777029 One of the lucky ones that just finished a B-2 for a fellow here down under with all 3 boards upgrade from @rottalpha. Amazing work everything laid up beautifully and the boards are top quality.
I have been lucky enough to have a few Yamaha Vfets go through my hands and own all the B's(although the B-2 I own is waiting patiently for this upgrade)
This particular unit has the Gold Tune on the filter board. The difference from the start was very noticeable. The B-2 highs had more air and with so much nuance and movement than prior the upgrade.
I listen to a lot of ECM records and the B-2 was able to extract more information and I could almost feel the air around the instruments, shimmering cymbals and long lasting piano decays.
I can confidenlty say that the upgraded B-2 is now a notch above my Sony TA-N7(which has been rebuild completely) Congratulation on your work Pete and thank you for this mod.
The listening that I did was with the Direct In option. Looking forward to do mine now
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Thank you Alex for making another vfet amp owner happy. I am glad to see that the Ausie v-fet club is stronger than ever and looking forward to your own unit getting rebuilt :thumbsup:
 
rottalpha said:
nope, and neither do the other vfet amps. They take turns and every time I hear one that I did not hear for a while, I get enthusiastic abut it just as the first time.


The problem for me when it comes to the B-2s is that every time I restore one, it end up making its way to someone else. That is a good and a bad thing. Good because the vfet love is shared, Bad because the "shoemaker ends up with no shoes".
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you mean less shoes ;) lol

Athanasios
 
Guys, I have seen some of you have the chassis done with some kind of electroplating . What is that processed or "patina" called?

Looking for a place here in Western NY that could do the basket case B-2 project.

Athanasios
 
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