Still popular and useful for HF Kilowatt RF amplifiers used on the ham radio bands.
My favorite is that one Gigabyte PC motherboard that had a single tube audio amp on it. Talk about silly...
I wish I had three hands....
This is a triple face palm.
Oh no, a child might burn his hand on a hot thing or cut himself on a sharp thing! REGULATE!
Hope you are joking.. Glass cups are not electronic devices. There is NOT a safety regulation for them...
Wall outlets in any country (outside US and the other who use US type sockets) do not have user accessible parts.
If you want to have accessible LIVE part in your house, that's you choice, but no manufacture should be allowed to sell them to you.
HOT for me refers to temperature, not mains voltage (in fact the max voltage inside that amp is 12 V dc). Tubes are hot, a child can burn his hands by simply touching it, and the blue LED is an attraction.
Well you still know if the operator at the other end has valve audio preamp even if you have a solid state receiver.
Similarly an old 50’s SW valve radio is the best audio for HF I’ve yet heard.
Hope you are joking.. Glass cups are not electronic devices. There is NOT a safety regulation for them...
Alas, very noisy people love the idea of an unregulated world. They think everyone's life and health is disposable, especially the stupid. They think that they are so smart as to avoid all danger. They don't realize that young children are incredibly ignorant (and will hopefully be able to grow out of it someday). They don't realize that there are ordinary lapses in attention or awareness that, rather than causing a permanent disability, could simply be met with an "oops" if there were some protection in place.
Lets say you have a sauna. You can pour water on the hot stones to increase the humidity. Do you really need an instruction to tell you that 1) stones are hot, do not touch them and 2) do not pour gasoline on them?
I built my tube amp without the shield. I actually told somebody that it was OK if he wanted to touch the tubes while the amp was on, it's just that parts of the glass were about 150C.
I think we are all missing the point here. This was sold for about 50 bucks. No true "audiophile" would buy a 50 dollar headphone amp, so this is not "audiophile quality".
Now, if you would sell the same thing for 500 dollars, it would be a different story...
How high is the anode voltage used and how is it created in this headphones amp?
About 24v total (-12 on cathode, +12 on anode) and two small switching regulators are used to create the voltage rails.
The grid is positive wrt the cathode!?
It's running in enhancement mode (to borrow a mosfet term). The data sheet gives data for depletion mode. I suppose that's a consequence of running the plate voltage so low. It's not a mode that's characterized on the data sheet. What do the curves look like for this mode? A spice model probably couldn't be trusted to give the correct result for this region of operation.
Obviously not valves with a top hat anode connection at 750 Volts then.
Hope you are joking.. Glass cups are not electronic devices. There is NOT a safety regulation for them...
Alas, very noisy people love the idea of an unregulated world. They think everyone's life and health is disposable, especially the stupid. They think that they are so smart as to avoid all danger. They don't realize that young children are incredibly ignorant (and will hopefully be able to grow out of it someday). They don't realize that there are ordinary lapses in attention or awareness that, rather than causing a permanent disability, could simply be met with an "oops" if there were some protection in place.
So rather than assessing whether a danger is a necessary part of the object (e.g. knives need to have sharp edges) or whether it is just cheap, lazy design (e.g. not putting a guard around a rotating fan), their knee-jerk libertarian reaction is to declare that all suggestions to insist on design that is rooted in human behavior (and error) are worse than worthless, coddling the incompetent.
Hope you are joking.. Glass cups are not electronic devices. There is NOT a safety regulation for them...
Alas, very noisy people love the idea of an unregulated world. They think everyone's life and health is disposable, especially the stupid. They think that they are so smart as to avoid all danger. They don't realize that young children are incredibly ignorant (and will hopefully be able to grow out of it someday). They don't realize that there are ordinary lapses in attention or awareness that, rather than causing a permanent disability, could simply be met with an "oops" if there were some protection in place.
So rather than assessing whether a danger is a necessary part of the object (e.g. knives need to have sharp edges) or whether it is just cheap, lazy design (e.g. not putting a guard around a rotating fan), their knee-jerk libertarian reaction is to declare that all suggestions to insist on design that is rooted in human behavior (and error) are worse than worthless, coddling the incompetent.
The sad reality is that the majority of people's lives *are* disposable. People want to think every life is sacred and everybody is a unique special snowflake. They're not.
There's billions of people alive on this pale blue dot, if any one of them disappeared tomorrow, 99.999999...% of the rest wouldn't notice or care. It happens every day.
If every life *was* sacred then the money and time first world countries (whose quality of life and mortality rates are pretty damn good) spent on THINK OF THE CHILDREN causes would instead go to *actual* children who are drinking filthy water and starving to death in third world shit holes, the world might be a better place.
But it's not. Instead, it goes to making sure little Johnny doesn't suffer the physical and emotional trauma of getting a boo-boo. Proving that people are greedy, selfish and value some lives more than others.
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The grid is positive wrt the cathode!?
It's running in enhancement mode (to borrow a mosfet term). The data sheet gives data for depletion mode. I suppose that's a consequence of running the plate voltage so low. It's not a mode that's characterized on the data sheet. What do the curves look like for this mode? A spice model probably couldn't be trusted to give the correct result for this region of operation.
Look here http://klausmobile.narod.ru/testerfiles/6j9pe.htm
The grid is positive wrt the cathode!?
It's running in enhancement mode (to borrow a mosfet term). The data sheet gives data for depletion mode. I suppose that's a consequence of running the plate voltage so low. It's not a mode that's characterized on the data sheet. What do the curves look like for this mode? A spice model probably couldn't be trusted to give the correct result for this region of operation.
Look here http://klausmobile.narod.ru/testerfiles/6j9pe.htmWhat's the difference in meaning of "Grid" and "Grid Drive" in the voltmeter section? Is this the voltage across a grid current sense resistor?
A modern tube tester. Cool!
A grid is a physical thing, conductive circular mesh surface placed between the cathode and anode of a tube. Grid drive is a voltage (AC + any required DC bias value) that will effect/control the current conduction between the anode and cathode terminals.
One question that pops up in my mind : could the "quality" of the 6V supply affect the quality of the sound by modifying the power of heating element (and thus the electron flow) ?
One question that pops up in my mind : could the "quality" of the 6V supply affect the quality of the sound by modifying the power of heating element (and thus the electron flow) ?
In some primitive (or high-power) tubes, the heater is also the cathode. But for almost all tubes used for audio, the cathode is a metal tube/oval with the heater filament wires INSIDE for indirect heating. So the actual current through the heater isn't really "in the circuit". Most tube heaters were operated directly from mains-frequency (50/60Hz) AC power. The thermal mass of the heater completely swamps out any effect from the sine-wave power of the heater current waveform. In exactly the same way that nobody can actually perceive "flicker" from an incandescent lamp operating at mains frequency.
Of course if circuit design or execution is sloppy, (or component failure) it is possible for the heater AC "hum" to get into the signal path. But that is an exceptional condition and not commonly found in properly designed circuits.
"Golden ears" audiophools imagine they can "hear" the difference between AC and DC power in an indirectly-heated filament tube. But they imagine lots of other things also, so that comes as no particular surprise.