It does say this, though.
Yamaha B-1 Alert
- Thread starter Elroy
- Start date
It does say this, though.
That does not apply to v-fet amps.
Edit:
See this post in this thread: http://www.audiokarma.org/forums/showpost.php?p=5432537&postcount=4
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VFET is a depletion mode FET. Without the -200 supplied at the gate (pinch off) it will conduct current from the source to the drain until it destroys the device.
With a regular transistor it takes current flow at the base to switch and allow the transistor to flow current from collector to emitter. No voltage or current at the base -no current flow between the emitter and collector.The VFET operates the other way around.Using the pinch-off voltage at the gate to throttle down the amount and duration of current flow from source to drain.
With a regular transistor it takes current flow at the base to switch and allow the transistor to flow current from collector to emitter. No voltage or current at the base -no current flow between the emitter and collector.The VFET operates the other way around.Using the pinch-off voltage at the gate to throttle down the amount and duration of current flow from source to drain.
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I still wouldn't flirt with destroying unobtainium FET's
To add insult to injury. Say if one VFET goes tits up. Your going to have to find a pair with the same ranking ie (matched pair). These are usually found attached to another B-1 amplifier.
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4seatPilot
"Broker"
that's about how my thought process is going with this one too. it's not hard to rig up a 220v adapter from a dryer plug and give it a real test. most likely it doesn't work, so a little creative wording and hope for a sucker.
I'm not bidding... that's for sure. maybe the buyer will get lucky and the problem will be in the protection circuit, but it might just be a big black doorstop.
Elroy,
all my experience of having overseas gear hooked-up to step-up transformers,is that it doesn't matter about the 50Hz/60Hz thing.
Where it really matters,is with turntables that use synchronous motors.They take their speed from the mains frequency.
Uncle Paul
Super Member
Knowing that the seller got this at a swap meet tells me that he is active in the hobby and knows what this is. I can't imagine anybody getting their hands on a B-1 and not hooking it up and listening to it. Almost every house has 220 available...
It would be a crying effing shame if he destroyed the VFETs by plugging it in to 120v.
4seatPilot
"Broker"
I'd bet that it shipped with a different plug and someone has changed it. Whether it was the seller or whoever he got it from at the swap-meet, jury is out on that one.
A shame indeed if that simple brain-dead move :bash: destroyed the amp...
cubby01
aka Buck
I wonder when that cord was put on. I'm no Yamaha expert but I'm guessing it's not an original Yamaha cord for any amp. ... So begs the question, what happened to the original cord. Maybe it was one of those 'cord cut' finds and someone thought they could just wire in a new one -- looks like they did a nice job though which leads me to think that's not the case. Or maybe someone had the amp converted from 240 service to 120? hmm, now there's a thought. Regardless, unless the seller indicates it works or you can visit it yourself, I'd be assuming it's just a parts unit with a pretty face.
i"m curious about this amp, never heard of one or seen one. Is it really that good ? can it hang with an sx-1980 ? what makes it so good ? and why would yamaha make it 220, you would have to have the living room re-wired to be able to play this thing. Why not just buy a mac, sorry for all the questions just trying to understand....Roost
cubby01
aka Buck
Pffttt. 'scuse me for a moment while I wipe down my screen.
[edit: maybe slightly unfair
I believe they were king of their respective hills during their day. But I have a soft spot for Yamaha, too bad these old B1/B2 amps will likely never find a way to my system.]V-Fets, look 'em up.
220v is used in other parts of the world. I believe there are actually some advantages to running off of 220 but that's neither here nor there. See Wikipedia on electricity by country.
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It might just have been converted to 120v. That is not a 220/240v plug by US standards and that is very much a US plug although I'm not sure if any foreign countries use that 3 prong plug.
Elroy
was here.
The Yamaha B-1 was a reference amp in the 70s and was in a different league than a SX-1980. When it debuted it was one of the finest amps in the world. VFETs never caught on though and the technology never became mainstream (bean counter unfriendly?). Others can say more specifically about why VFETs were superior to standard bipolar transistors.
This specific amp is 240V because it is a European unit. They made US 120V units as well.
This specific amp is 240V because it is a European unit. They made US 120V units as well.
It makes a 1980 sound like ass.
