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WAWASEE JB 2000 Specs
- Thread starter unit_399
- Start date
Yup, and they have more b+ and on xformers that really don't sag
still i find it so funny how the calculator doesn't lie. I've amazed people time and time again with Ohms law
It might be different in your neck of the woods but here in Alabama most people don't know the difference between input and output wattage, they just see the big numbers so that must be what it will do.
then they hook em up to some rusty ol' dosy test center that will show a barefoot pro510 swinging 83W and can't believe their eyes when they see a JB2K bending the needle on the 2KW scale.
hehe... thinking about that brings back memories of when I used to preach to a local, self taught, amp building guru that swore he was getting over 2kw out of a quad of 6164s...
IIRC, the 3-500Z tube can be fed with up to 4k volts and put out 'mo powa'. SO, the weak link is the power supply. The Swan Mk II amp I have has two 3-500Z tubes in it with a transformer that will put out close to 3.6kv (a 'Peter Dahl' xformer) and ~1.7kw. The stock xformer would only do ~2.8kv and put out ~1.3kw. If you are getting a kw with the xformer/supply that you have now and you paid so little for it all; then you are ahead of the game . . .
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Easy enough to explain.
Yes you can get 2kw from a pair of 3-500Z
If you have the PS to handle it. You will be driving the snot out of the tube and severly cutting tube life but it can be done.
Same as the formula which I posted before in a closed thread.
P=E*I*efficiency
Henry amps run right at 4000VDC for B+
4000*.75ma*66% efficiency= 1980 watts
Heathkit SB1000 a single 3-500Z has 3400 VDC on the plate.
It will produce more or less the same output as an SB220 with a pair of 3-500Z.
Now the question is why? The FCC regulated amplifiers by input power when the Heathkit SB220 were being sold.
Then it was changed to regulate by output power to 1500w.
Some of the amplifiers being sold today will exceed legal limit easily, it is up to the op to keep the power output legal.
Yes even the hams run illegal power, some more than others.
It is all in the power supply and tank components
Yes you can get 2kw from a pair of 3-500Z
If you have the PS to handle it. You will be driving the snot out of the tube and severly cutting tube life but it can be done.
Same as the formula which I posted before in a closed thread.
P=E*I*efficiency
Henry amps run right at 4000VDC for B+
4000*.75ma*66% efficiency= 1980 watts
Heathkit SB1000 a single 3-500Z has 3400 VDC on the plate.
It will produce more or less the same output as an SB220 with a pair of 3-500Z.
Now the question is why? The FCC regulated amplifiers by input power when the Heathkit SB220 were being sold.
Then it was changed to regulate by output power to 1500w.
Some of the amplifiers being sold today will exceed legal limit easily, it is up to the op to keep the power output legal.
Yes even the hams run illegal power, some more than others.
It is all in the power supply and tank components
Yeah...a single new 3-500z goes for about $170...you could prolly turn around and sell that amp for $500....working JB 2000 are kinda rare......one in mint condition will fetch its original price of $850.
I have a Drake L4B with a pair of 3-500Z, the PS is not stock and it will slap the 1.5KW mark all day long with 70 watts of drive.
Autek-WM1 meter.
The Swan MKII is one heck of a bucking bronco of an amp!! I know because i used to own one...
Let me update that, I've seen a full amp of plate current draw from two 3-500ZGs at 4050v under load (4500v idle) and he's getting about 70% efficiency from a very well built custom mono-band amp for 40m.
He drives it with the 200w version FT-1000 MkV and regularly hits 2800w pep on his Bird pep meter. He's still running the same set of tubes he's had for the last 4 years without any loss in output.
He cools them VERY well by pumping cool air into the RF deck from a large outdoor squirrel cage fan and exhausts back outside.
The RF deck cooling is sealed off from the room so it's barely audible and you can't hear any fan noise in his background, but he is also running a downward expander.
I'm accumulating parts to build one like it, though a set of 4-1000s sure is tempting, they're just so darn big and hard to find.
200 watts drive? What is the grid current? Excessive to say the least.
I have seen 11 meter "BOWL" boxes built around the 3-500Z.
The tube has got so hot from being over driven that the solder in the pins actually melted.
Now what is the difference in signal strength between 2800 watts and 1500 watts?
Not trying to start an argument just pointing out that that type of output does not really accomplish anything.
Better to run the equipment at manufactures specifications and also keep it legal according to the license.
I have seen 11 meter "BOWL" boxes built around the 3-500Z.
The tube has got so hot from being over driven that the solder in the pins actually melted.
Now what is the difference in signal strength between 2800 watts and 1500 watts?
Not trying to start an argument just pointing out that that type of output does not really accomplish anything.
Better to run the equipment at manufactures specifications and also keep it legal according to the license.
Yeah, He turns it down to around 140-160w pep I believe, but the cooling is so efficient there's no chance of melting tubes nor un-soldering pins.
And as far as the difference between 2800w & 1500w, when he doubles with someone else running 1500w or so...
They hear him.
A little more than 1.5DB is the difference between 2800w vs 1500 watts? sure beating the heck out of those triodes for a little bit more gain.
1500w to 3000w would be 3dB gain, the 7% difference between 2800w & 3000w is negligible. They still hear HIM.
Or a YC156.