The malady lingers on

Well, my love for the JVC VFET continues. As one does, I occasionally punch in "VFET" while on ebay, and a few days ago something surprisingly appeared.

Without labouring the story, I am now the owner of a rather tatty and faulty Yamaha B2. It's a 100 volt model ex-Japan. The owner tells me that he turned it on one day and it emitted a weird sound, followed by a puff of smoke. Believe it or not this encouraged me to buy it, because VFETs are unlikely to emit smoke when they expire and I suspect either a power supply cap or, in the worst case, one of the power transformers.

Since the darned thing weighs in at 26kg (putting even the JM-S7 to shame) and I live in the country where couriers fear to tread, I'm having it delivered to my brother in Queensland. I need to visit soon to pick up a VW Transporter van that has been sitting in his yard while we've all been locked down by Covid. So it will go in the back for the return journey in a few weeks' time.

I'll let you know how the repair progresses and, if it can be made to work, how it compares to the JVC amp. In any case, at AU$500 it was a no brainer.

Edit: Forgot to mention, I checked to ensure it wasn't a dealer offloading an impossible repair. The seller also had a pair of Yamaha speakers and a 240-100 V stepdown transformer for sale, and he lived in a rather exclusive suburb, so that had no odour of fish at all. I think this one's a safe bet.
 

Attachments

  • My B2.png
    My B2.png
    326.8 KB · Views: 182
Last edited:
  • Like
Reactions: ranshdow
That means something completely different here in Australia. 🙂
I once had to change the title of the manuscript for an article from "Square rooting circuit based on a novel, back-gate-using multiplier" into "Root-of-x circuit based on a novel, back-gate-using multiplier" because the original title very much upset the lady who checked the manuscripts for language errors. In fact she thought it was "some kind of sick joke".

Anyway, good luck with your amplifier!
 
Last edited:
I once had to change the title of the manuscript for an article from "Square rooting circuit based on a novel, back-gate-using multiplier" into "Root-of-x circuit based on a novel, back-gate-using multiplier" because the original title very much upset the lady who checked the manuscripts for language errors. In fact she thought it was "some kind of sick joke".

Anyway, good luck with your amplifier!
As I always say, there's nothing like a good square root. 🙂
 
Well, my love for the JVC VFET continues.
I can say from experience that if you love the JM-7 you'll likely love the B-2 just a tad more. That said, the Victor is a wonderful amp and a joy to listen to. Both drive my NS-1000M's with a sonic synergy that just keeps me coming back for more.

Like your B-2, I took a chance on the JM-7 hoping that the V-FET's were still intact even though the seller said his tech claimed all Ks were toast which is why no one else wanted it and I got it for what I did.
 
Especially when using "a novel, back-gate"...? 😆😆

No wonder the poor lady was upset 🤣🤣
It was at the Delft University in 1993. Neither I nor my then mentor and co-author Jeroen Kuenen knew what rooting meant in Australian slang - how were two Dutch guys to know?

So I sent the manuscript to Mrs. Zaat-Jones, the lady who checked for language errors, with a note that she could send it to Jeroen when she was finished. Some time later Jeroen got a phone call from her; she said that the article was allright, but there was something about the title that was so bad she didn't want to discuss it over the phone, and asked if she could come to his office. Not having a clue what could possibly be wrong, Jeroen agreed. Mrs. Zaat-Jones came into his office, threw the article on his desk, pointed at the title and asked: "Is this some kind of sick joke?"

It turned out that it was indeed the combination of a rooting circuit and a back-gate-using multiplier that had upset her. If we had only used the term rooting, she would probably have assumed that we didn't know the slang meaning, but the combination was a bit too coincidental.

http://bioelectronics.tudelft.nl/~wout/documents/el94.pdf
 
Last edited:
If they are in good condition, probably. Not my style, but getting. pair so that they can be properly be made into a mirror imaged pair.

dave

The guy even offered to ship them to me through his company's courier and include that in the price. I was sorely tempted but that wouldn't be doing justice to the two dozen or so Jordan drivers that I have yet to put into enclosures. Besides, they would need to be put on stands and so take up half the living room.
 
I sure did. All all V-FETs were fine.

It's missing the serving tray side handles and the thermal sensor was toast but it was otherwise working fine and sounding superb. 🙂
Well that's encouraging. 🙂

The side handles are just an extrusion, I'm sure you could find something similar. It was probably rack mounted at one time.
 
Last edited: