There's a build up of free electrons around the negative terminal. When the bias is removed some will diffuse back into the metal.
Inductors can be lethal too. I read in a book on the history of physics that somebody in the mid 1800's killed himself when he was holding both leads of an inductor when the current was interrupted.
Inductors can be lethal too. I read in a book on the history of physics that somebody in the mid 1800's killed himself when he was holding both leads of an inductor when the current was interrupted.
Caps can be charged by static in the air and even RF. I once made the mistake of disconnecting the feeder and floating an array of nine 500' AM towers during an overnight transmitter repair. One touch of the disconnected line left an indelible impression.
that was static buildup...... the large surface area of the antenna towers and a little bit of wind can cause very large buildups of static. it's the same thing that happens to helicopters in flight.
large caps are dangerous to leave around charged. it's a safety hazard.
leaving a jumper across the cap is probably a good idea. i know it's definitely a good idea with picture tubes. when i was doing computer monitor repair, i got bit more than once by picture tubes that had been completely discharged a day or two earlier. esoecially the tubes used in Amdek color monitors. the particular type of glass used for those tubes had very high dielectric absorption, and the anode cap was on the side of the tube and the chassis was about 1/2" away from the anode cap, which made for a tight squeeze with your fingertips while reconnecting the anode cap. within 24 hrs after being completely discharged, the anode voltage had climbed back up to about 1/3 of the operating voltage. after getting bit a few times, i made it a habit to keep a clip lead attached between the anode cap and the ground strap on the tube whenever the guts were out of the monitor
large caps are dangerous to leave around charged. it's a safety hazard.
leaving a jumper across the cap is probably a good idea. i know it's definitely a good idea with picture tubes. when i was doing computer monitor repair, i got bit more than once by picture tubes that had been completely discharged a day or two earlier. esoecially the tubes used in Amdek color monitors. the particular type of glass used for those tubes had very high dielectric absorption, and the anode cap was on the side of the tube and the chassis was about 1/2" away from the anode cap, which made for a tight squeeze with your fingertips while reconnecting the anode cap. within 24 hrs after being completely discharged, the anode voltage had climbed back up to about 1/3 of the operating voltage. after getting bit a few times, i made it a habit to keep a clip lead attached between the anode cap and the ground strap on the tube whenever the guts were out of the monitor
I had a fire once from a 'discharged' computer grade electrolytic that was put in a metal storage drawer along with some steel wool.
(although I did not do a double blind test on this either)
(although I did not do a double blind test on this either)
Wingfeather said:
Bollox.
You're all still talking about this?
An amplifier is about as interesting as a hammer.
As has been amply demonstrated, it is entirely possible for a person with wildly inconsistent views to design a successful amplifier.
Designing a hammer is something a stylist does as a small fraction of their total job.
The same is becoming true of amplifiers. They are being perfected. When they are perfect, they will be indistinguishable in performance. The only argument can be about what levels of imperfection are perceptible.
Does anybody dispute this? Or is there someone out there who thinks that mankind is still searching for the perfect hammer?
Hammers are good enough.
Amplifiers are pretty much good enough
w
Not all hammers are created equal.
Have you noticed how many different simple hammers you can buy, each optimized for a certain job?
Now think again.
Have you noticed how many different simple hammers you can buy, each optimized for a certain job?
Now think again.
wakibaki said:
That's a philosophical order argument. The way you put it you are right. Any hammer will drive a nail home.
For any practical purpose, If I need a car as a salesman, then whatever the company provides is adequate. The inexpensive car tech is evolved enough for everybody so to get them safe and under speed limit anywhere.
If the order changes, into say, what hammer fits your palm, technique, muscle power and agility, material to be pounded, hammered finish type etc. Then welcome to the world of hammer classes.
wakibaki said:
Yes. There is no perfect amplifier (at this point in time, i'd say we aren't even that close). Maybe if there was only 1 loudspeaker, but even then we still have quite a bit to learn.
1st off we are building with imperfect devices. Invention of a new device will require us to start the climb of the learning curve again.
dave
Now I fee guilty about the things I'm interested in. The history and design of hammers is a relatively big topic, and the perfect hammer has yet to be designed. Different people will have a different opinion about the same hammer used for the same job. How do you test a hammer? Does it have to be a DBT? If the user knows it's a $10,000 gold plated government hammer, does that change his/her opinion about how well it hammers? What about the users of plastic vs. leather vs. lead vs. brass dead blow hammers? And wooden hammers? I bet tube users prefer wood. John Henry probably had a lot to say about hammers, and about how those steam driven digital hammers took the joy out of hammering.
Andre Visser said:
Well blow me! All those different hammers, and I never noticed!
Now you're just being obtuse.
w
planet10 said:
You say yes, you're going to disagree with me, and then you don't. Exactly how does what you said contradict what I said?
I never said that amplifiers are perfect, I said they are approaching perfection.
The whole point is that amplifier performance cannot go on getting better and better infinitely, as some people appear to believe. They can get smaller, cheaper, more efficient, but as in the case with efficiency there is a limit to how 'good' they can get. You can only get 100% efficient. You can only get zero distortion, not negative distortion, and the last few percentage points just aren't worth chasing, and nobody in the engineering community is going to help you dorks chase them. That's why we're engineers and you're dorks. And, incidentally, why the people who continue to encourage your misplaced spending aren't. Either dorks or engineers that is, if you get my meaning.
w
wakibaki said:
Hey, we don't buy amps here, we create them! This is DIY audio, remember? After all creativity is the highest of highs. Even if not practically meaningful to some. I bet that John Curl will be matching FETS even when Radio Shack will be selling 100% efficient 1kW 0% distortion D amps for $100.
Lest anybody misunderstand, I am currently assembling 2 audio amplifiers from components myself, and I have started sketching out a design for a tube amp for my guitar. This is about the only excuse I can think up to play around with valves, other than a VHF transmitter, but I haven't spoken on the radio for years, although I still have a license for full power.
w
w
And i saud "at this point in time, i'd say we aren't even that close" to the perfect amplifier.
dave
Conrad Hoffman said:
They sure did!!
But those air powered nail guns sure are sweet. 🙂
Speaking of which, whatever happened to the compressed air amplifier?
planet10 said:
Yeah, and how does that contradict the main thrust of my argument?
I agree, we aren't even close. OTOH we're extremely close. Both of these statements are equally meaningless, and, more to the point IRRELEVANT.
If you haven't got anything to contribute except noise why do you persist in posting?
w
wakibaki said:
Seeing that you are the only (deaf) engineer here, don't worry, nobody here will, or need to ask you for your help.
(I bet here are a lot of real engineers that don't need to tell it to everybody.)
What, me, worry?
It's always the same with you flakes, you get hold of somebody rational, you just can't let go...
w
It's always the same with you flakes, you get hold of somebody rational, you just can't let go...
w
Alot of bolony and hot air
It seems some have a long way to go yet, learning how to do it right and get the most of it
The only real weak link today are the recordings
It seems some have a long way to go yet, learning how to do it right and get the most of it
The only real weak link today are the recordings
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