John Curl's Blowtorch preamplifier part II

[bcarso]

I am quite content we havent met them.

Recommended sci-fi story: Don A. Stuart (John W. Campbell), Forgetfulness.

A quote:

"Once"--Ron Thule's voice was tense--"the city builders made atomic generators to release the energy bound in that violent twist of space called an atom. He made the sorgan to distribute its power to his clumsy shells of metal and crystal--the caves that protected him from the wild things of space.

"Seun has forgotten the atom; he thinks in terms of space. The powers of space are at his direct command. He created the crystal that brought us here from the energy of space, because it made easy a task his mind alone could have done. It was no more needful than is an adding machine. His people have no ships; they are anywhere in space they will without such things. Seun is not a decadent son of the city builders. His people never forgot the dream that built the city. But it was a dream of childhood, and his people were children then. Like a child with his broomstick horse, the mind alone was not enough for thought; the city builders, just as ourselves, needed something of a solid metal and crystal, to make their dreams tangible."

 

[Esperado]

I am quite content we havent met them.

If our anthropologists had a way to observe the last tribes of primitive civilizations on our planet, with a way to stay invisible, do you think people in those tribes to have any chance to "met them" ?

 

[jacco vermeulen]

a very unusual culture for sure.

One does not need to enjoy drug dealers*, to monitor/study them for years, at probing distance.
As it so happens, I have an active interest over the last half decade in the who/what on Curaçao, as an update.
Small island with a population of only 150k, but very close to Colombia and lots of dope.
I like to know the place I spend a lot of time, the neighbor, and the next-door neighbor, call me stupid.

An old saying on the island is that if someone breaks wind on West-Point, it can be heard on East-Point 15 minutes later.
What an unusual culture, the wind there is always due West.

Maybe a reason for some to trade with Japan for a few centuries, while all other West-bound didn't.
A matter of eyeballing, not preference.
Examination without eyeballing implementation, is ignorance.

(most of the names/faces that appear familiar to me, didn't make it in the long run. a couple were very shortlived, some even may say by the whisper of the right words in the right ear. ah, the encredulous/immoral stories I wouldn't tell, who cares about aliens)

 

[BigE]

You are right, Lucky. Now if only everybody else could be equally open minded. '-)

Just so we're on the same page:

It appears that Luckythedog was saying that he thought you learned that the LED noise you've been promoting as problematic was inconsequential.

Learning does not require an "open mind". It requires a mind willing to learn. *Big* difference among audiophiles.

 

[jacco vermeulen]

the price per oz/gm of egg

(If I answer that one, you'll view me as anal probing fixated)

 

[dimitri]

ok, I placed two T1 green LEDs in the black tube face to face, one lens touches another. I set 5mA dc current through each LED. Then I added ac current 5mA pk from AP Sys2 to one LED - transmitter (100% modulation). Here are ac measurements on receiver LED pins
1kHz - 1.8uV
5kHz - 4.4uV
10kHz - 7uV
20kHz - 10uV
Clearly the level becomes higher with frequency, so to check if this is capacitive coupling with transmitter LED I made current through receiver equal to 0. On receiver LED pins I got
1kHz - 1.8uV
5kHz - 4.4uV
10kHz - 7uV
20kHz - 10uV
Both LEDs were powered from galvanically isolated power supplies.

 

[Chris Hornbeck]

Those interested in the origins of you know, Life the Universe and Everything, might like Stuart Kauffman:

http://www.amazon.com/gp/product/0195095995?psc=1&redirect=true&ref_=oh_aui_detailpage_o09_s00

and Lee Smolin, at least his first book:

http://www.amazon.com/Life-Cosmos-L...TF8&qid=1443222166&sr=1-5&keywords=lee+smolin

All good fortune,
Chris

 

[SY]

-106dB at 20kHz. And if we follow the trend to 60Hz (the frequency I used since that's where lights flicker), more like -130dB. And that's with the light source at zero distance. No wonder I couldn't measure any effect!

Yeah, I think we can dismiss that as anything significant.

 

[Esperado]

I set 5mA dc current through each LED.

By simple curiosity (I have found better photo diodes ;-) what was the output impedance of the reciever's power source ?

 

[john curl]

Thanks Dimitri for actually making a measurement.

 

[john curl]

I tried a measurement with an HP339, with and without DC bias, using a flickering flashlight in a dark room. I got output in both cases.

 

[Bonsai]

Dimitri, Common mode noise coupling? What if you pulled the LED's apart a bit?

If it's not that, maybe someone up on their solid state physics can explain the mechanism.

 

[31697B]

UFO? The possibility and probability of life elsewhere seems to be something greater than zero. However, it is just as likely (which I believe true) that we are a fluke of the universe.


-RNM

 

[Bonsai]

Well, we are orbiting smack in the middle of the Goldilocks zone,many it appears that planets orbiting in this zone around other stars are quite common (by that I mean > 0.1% of observed exo-planets).


But, we are straying from thr important subject here which is LED noise pick-up from flickering lights.

 

[john curl]

My measurement did not have any significant coupling, but found added noise from a flickering light.

 

[EUVL]

Great measurement Dimitri. Many thanks.

I wonder if you add a 0.1µF MKP or PPS in parallel with the receiver LED, whether the noise is still the same.
(We do normally use a cap in parallel with an LED used as voltage reference, don't we ?)


Patrick

 

[gerhard]

If this is to help, Xc must be much smaller than the source impedance
of the reference. 100n won't help much at interesting frequencies unless
the ref impedance is pretty high.

 

[AndrewT]

Are we suggesting that all the voltage reference LEDs inside our amplifiers should be sat in their own black boxes?

 

[Esperado]

If I remember well, the germanium transistor we used at the begining, remember, they were in transparent cases painted in black, were a little light sensitive, too. What about our transistors ?

 

[gerhard]

Are we suggesting that all the voltage reference LEDs inside our amplifiers should be sat in their own black boxes?

I usually make a blob of black lacquer on the SMD LEDs I use for this
purpose. Just to avoid surprises. And it hurts less in the eyes when
I look at the board from close.