Hey guys.
I just got a bunch, 30 pieces of so, of these really BIG capacitors, only because it was for sale at a very low price.
Now... Is there any use for such big caps in tube amps, or should I just try and resell them to buy other more useful parts?
Seems too big for tube amps for me. Most of what I see use 100 or 220uF high voltage caps, 470uF at most.
And just out of curiosity... What are those big 450v caps used for? Heavy industrial equipment, maybe? What else?
So... Should I just sell them for a burn price online, and buy me more tubes and transformers, or should I keep and use them on tube amps?
What you guys think?
Thanks on advance for any light on this subject!
I just got a bunch, 30 pieces of so, of these really BIG capacitors, only because it was for sale at a very low price.
Now... Is there any use for such big caps in tube amps, or should I just try and resell them to buy other more useful parts?
Seems too big for tube amps for me. Most of what I see use 100 or 220uF high voltage caps, 470uF at most.
And just out of curiosity... What are those big 450v caps used for? Heavy industrial equipment, maybe? What else?
So... Should I just sell them for a burn price online, and buy me more tubes and transformers, or should I keep and use them on tube amps?
What you guys think?
Thanks on advance for any light on this subject!
Attachments
Play with them carefully if you decide to use them. Hearing loss and vision problems can come from shorting the terminals when charged.
They most likely came from very large switching power supplies. I recently repaired the power supply from an IBM system/32 (late 1970s) and there was a 1000uf 450v can capacitor. I had no idea those values existed back then.
You could use them but a thermistor or soft start resistor would be a good idea.
Or parallel them up and build a can crusher. Check out YouTube for some examples.
You could use them but a thermistor or soft start resistor would be a good idea.
Or parallel them up and build a can crusher. Check out YouTube for some examples.
A bunch of them in series with bleeder resistors across them could maybe be useful for the power supply of a direct-drive amplifier for an electrostatic loudspeaker. With for example 20 in series, you effectively have a 205 uF, 9 kV capacitor.
The bleeder resistors (one per capacitor) help to get equal voltage division between them and to ensure that the voltage goes to zero after power-off. Discharging them for a short time is not enough because of dielectric absorption; 10 % DA at 9 kV is a still potentially lethal 900 V.
The bleeder resistors (one per capacitor) help to get equal voltage division between them and to ensure that the voltage goes to zero after power-off. Discharging them for a short time is not enough because of dielectric absorption; 10 % DA at 9 kV is a still potentially lethal 900 V.
Interesting! Perfect use for that technology would be for launching probes into space, à la Jules Verne, so that you don't need to bolt inefficient and heavy rockets to space craft.
Interesting they had no concept of a gramme! 500g, when it was 50g.
Interesting they had no concept of a gramme! 500g, when it was 50g.
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I have used 3300µF in tube amps. 4100µF isn't a stretch. Of course you'd use solid state diodes 🙂
By using such a large cap, the R in the RC filter can be smaller (in my case, 5R).
By using such a large cap, the R in the RC filter can be smaller (in my case, 5R).
My 1990 Vintage VTL monoblock amps use two 3800 uf 450 volt caps per amp in a voltage doubler circuit for the B+ power supply.
The anodes on the six 807 power tubes run at 550 volts.
Mine are 140 watts per channel and I know they made higher power amps, so I wouldn't be surprised to see that they used 4100 uf caps in the larger models.
They were actually saying "grains" which is the Grandfathered unit for firearms projectiles (and powder). IIRC, it's 1/7000 of an ounce. Clear as mud, but too late to change it now. 500 grains is the size of a 50 caliber bullet, but that "gun" is only moving it pretty slowly. Still, don't stand in front of one.
All good fortune,
Chris
Jules Verne wrote "From The Earth To The Moon" in 1865, when people had absolutely no idea how to calculate air resistance to a moving object. Also, I doubt they had any idea just how incredibly fast an object had to be moving, in order to escape the earth's gravity (known as the escape velocity).
A hundred and fifty seven years later, we know that the earth's escape velocity is about 25,000 miles per hour (https://www.qrg.northwestern.edu/projects/vss/docs/space-environment/2-whats-escape-velocity.html). This is the minimum (upwards) speed that is needed for a projectile to escape Earth and go into space; any slower, and the object will go up a bit, slow down, stop, and fall back down.
Now, 25,000 miles per hour is over 30 times the speed of sound (approx, as the speed of sound changes with altitude).
Can you imagine the amount of air-drag if you try to shove a spacecraft through air at 30 times the speed of sound? The air would be unable to move out of the way, so it is like pushing the spacecraft through molten tar. So much energy would be lost to drag, that even if you could fire an object out of a (rail) gun at such speeds, it would slow down and stop very quickly just from air drag.
And that is a very big "if" to start with. From a quick Web search, it's not clear that humankind has ever managed to move any sort of largish object through the air any faster than Mach 10. The fastest I can find is Mach 9.64 for NASA's experimental X-43 unmanned space plane: https://en.wikipedia.org/wiki/NASA_X-43#Operational_testing
When you start to think about all this, it becomes very clear why rockets destined for space start out relatively slowly, and only begin to really pick up speed after they've already passed through the thickest layers of the earth's atmosphere. Once the air is thinner, less energy is lost to drag. Once entirely clear of the atmosphere, it becomes practical to reach speeds high enough to leave Earth entirely behind.
Jule's Verne was an incredibly creative writer, and his stories were centuries ahead of his time. He got people imagining extraordinary things like trips to the moon, or to the bottom of the ocean. But that doesn't mean the fictional ideas from his books would actually work in reality.
-Gnobuddy
Even further off topic, rail guns (on the Moon!) were an essential part of Gerard K O'Neill's mid-1970s proposal for building habitats at Lagrange points, to be built from the metals and oxygen of the moon.
https://en.wikipedia.org/wiki/L5_Society
And initially, to send power from solar collectors, as microwaves, to Earth. See his book The High Frontier.
Although the era was deeply Cold War, with psychopathic national governments armed with nuclear weapons, just like today, there was a feeling of long term optimism, unlike today. We seem to no longer expect things to get better, and only try to keep things from not getting worse. We can no longer even go to the moon. People still go hungry, and will get hungrier.
May the Goddess bless us,
Chris
ps: a grain is 1/7000 of a pound. Sorry, brain fart.
https://en.wikipedia.org/wiki/L5_Society
And initially, to send power from solar collectors, as microwaves, to Earth. See his book The High Frontier.
Although the era was deeply Cold War, with psychopathic national governments armed with nuclear weapons, just like today, there was a feeling of long term optimism, unlike today. We seem to no longer expect things to get better, and only try to keep things from not getting worse. We can no longer even go to the moon. People still go hungry, and will get hungrier.
May the Goddess bless us,
Chris
ps: a grain is 1/7000 of a pound. Sorry, brain fart.
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“Suffer me to finish," he calmly continued. "I have looked at the question in all its bearings, I have resolutely attacked it, and by incontrovertible calculations I find that a projectile endowed with an initial velocity of 12,000 yards per second, and aimed at the moon, must necessarily reach it. I have the honor, my brave colleagues, to propose a trial of this little experiment.”
― Jules Verne
12,000 yards per second is 36,000 feet per second and Google tells me this is 24,545 MPH.
I'd say Jules was not as dumb as he looks.
In fact the moon is closer than a true escape and 400 MPH may be just enough lower.
Not that it matters. A fortuitous asteroid affects the launch and.... well, you can read it yourself.
Be aware that most of Verne's English translators messed with the stories. Omitting, adding, changing, even merging. The two "Moon" books are often presented as one.
I have read the book (a long time ago), and I never thought Verne was dumb. But I didn't expect that mid-19th century astronomers knew sufficiently accurate values for the earth's mass and radius, both of which you need in order to calculate the escape velocity.
I've read lots of books about the early halting steps towards heavier-than-air flight, and one of the major obstacles was that early attempts to calculate lift and drag for a flat plane moving through air were significantly flawed. So were early attempts to measure it.
Lacking good theoretical formulae, many experimental measurements were also made, including some by Gustave Eiffel, dropping wing sections from his own Eiffel tower. The experimental measurements varied widely from one experiment to the next, and from one experimenter to the next, and from one decade to the next. Nobody understood that the air outdoors tends to be quite turbulent, and nobody had a clue about what we now call Reynold's numbers, so with the benefit of hindsight, it's not surprising that reams of bad data were produced.
Everyone started with flat plates; it wasn't till after Lillienthal's successful gliders that people began to realize that curved surfaces worked much better than flat plate wings. And those were even harder to understand.
By the 1930s there was much better theoretical and empirical understanding of aerodynamic forces at typical propeller-driven aircraft speeds. But even by the end of WW II, the "sound barrier" was still unknown territory, and aircraft that approached too close to it tended to disintegrate in mid-air.
Mach 30, at low altitudes? If anyone has actually pulled that off with a sizeable vehicle, unmanned or otherwise, they seem to be keeping their mouths closed about it.
-Gnobuddy
Absolutely - transmitter supply perhaps, motor controller DC rail, induction welder, high power laser etc etc. I've used some for an electro-magnetic can crusher.
Talking of unworkable orbital injection methods, no-one's mentioned SpinLaunch?
E = 1/2 * C * V²
415.125j
4100uF 450V
Pumping somthing like this.
https://www.xenonflashtubes.com/uv-...0q-uv-quartz-flashtube-80mm-ipl-lamp_123.html
415.125j
4100uF 450V
Pumping somthing like this.
https://www.xenonflashtubes.com/uv-...0q-uv-quartz-flashtube-80mm-ipl-lamp_123.html
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And yet, at times he was pretty clueless.
I'm not concerned with Mach 30 in the atmosphere after what must be a 100+ Gee launch. On "sturdy couches" (albeit with a water-cushion under the capsule). One guy wakes up, wakes another with prolonged rubbing, they wake the third guy with almost a chapter of rubbing. Then they settle their bets(!), eat, take a nap. Then they notice the one dog is hungry, and the other is in the loft with a fractured skull. After a bit they open a window, quickly so as not to loose too much air (they have oxygen but not the inert gases), and throw him out. And are astonished he is still there the next day, but figure it out. Meanwhile they are walking and working like they have gravity. Their gravity does not fail until very close to the Moon, the null point. A wine-glass (glass! on a moon-ship!) floats. The dog jumps and stops (how?) in mid-air.
He "figures" air drag as 1/3rd of initial speed. 18,000y/m at launch, 12,000y/m at top of atmosphere. No explanation given.
There IS a long passage about calculating the velocity. With something called Algebra.
“So be it,” said Michel; “but, once more; how could they calculate the initiatory speed?”
“Nothing can be easier,” replied Barbicane.
“And you knew how to make that calculation?” asked Michel Ardan.
“Perfectly. Nicholl and I would have made it, if the observatory had not saved us the trouble.”
“Very well, old Barbicane,” replied Michel; “they might have cut off my head, beginning at my feet, before they could have made me solve that problem.”
“Because you do not know algebra,” answered Barbicane quietly.
“Ah, there you are, you eaters of x^1; you think you have said all when you have said `Algebra.’”
“Michel,” said Barbicane, “can you use a forge without a hammer, or a plow without a plowshare?”
“Hardly.”
“Well, algebra is a tool, like the plow or the hammer, and a good tool to those who know how to use it.”
“Seriously?”
“Quite seriously.”
“And can you use that tool in my presence?”
“If it will interest you.”
“And show me how they calculated the initiatory speed of our car?”
“Yes, my worthy friend; taking into consideration all the elements of the problem, the distance from the center of the earth to the center of the moon, of the radius of the earth, of its bulk, and of the bulk of the moon, I can tell exactly what ought to be the initiatory speed of the projectile, and that by a simple formula.”
“Let us see.”
“You shall see it; only I shall not give you the real course drawn by the projectile between the moon and the earth in considering their motion round the sun. No, I shall consider these two orbs as perfectly motionless, which will answer all our purpose.”
“And why?”
“Because it will be trying to solve the problem called `the problem of the three bodies,’ for which the integral calculus is not yet far enough advanced.”
“Then,” said Michel Ardan, in his sly tone, “mathematics have not said their last word?”
“Certainly not,” replied Barbicane.
“Well, perhaps the Selenites have carried the integral calculus farther than you have; and, by the bye, what is this `integral calculus?’”
“It is a calculation the converse of the differential,” replied Barbicane seriously.
“Much obliged; it is all very clear, no doubt.”
Biggest i've come across were the 2000 uF beer cans on the Paoli 60M. Yours dwarf those, though. Wow.
Variations on that sort of mistake are still regularly made by Hollywood, more than 150 years after Verne - screen-writers and directors who don't seem to have the faintest understanding of how forces work.
Remember the Six Million Dollar Man, picking up heavy trucks with his super-strong robotic arm? Nobody seems to notice that arm is attached to a fragile human skeleton made of bone, and all forces from the bionic arm are inevitably transmitted straight into the ordinary human skeleton, which would crumble under the weight of a military truck...
You reminded me that I have forgotten a lot of details from "From The Earth To The Moon". All Jules Verne books are out of copyright, which means we can legally download them, free of charge, from Project Gutenberg. Here is the specific book under discussion: https://www.gutenberg.org/ebooks/83
-Gnobuddy