John Curl's Blowtorch preamplifier part II

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It was 500-550nT and the change averaged 50nT only 10% (hardly de-magnetized). So this effect two orders of magnitude less with a change of three orders of magnitude less than the earth's background is "dramatic".

I can change the background field by 50 nanotesla just by holding my breath. Turning blue adds another 22 nanotesla (hemoglobin concentration).
Passing out, well, I don't know, I was unconscious at the time....;)

I can assure you the wife in the kitchen wielding knives and opening and closing all those magnetic latches is a larger effect. Maybe jn could compute it. :)
No can do...sorry. I stay out of the kitchen when my wife is "wielding knifes"... While I may be in her good graces now, ya never know.. the day is young..

jn
 
Not even close. PC molecules are essentially unaffected by magnetic fields. You might get some re-orientation under high electric field combined with heating above Tg, but why bother? Read errors are pretty infrequent, it's a robust medium. And like all other physical media, it's going away in favor of downloads.

have you ever measured the read errors on a CD? Checked to see what the uncorrected ones are?

Well I have.

The results are very clear. In normal Audio CD's the error rate is embarrassingly low with a decent player. However I do have some players that really can't recover the information without lots of errors.

There is an easy way to reduce the error rate of the poor performing CD players. You will find this hard to believe, but sprinkling chicken blood on it by a religious practitioner and then backing a car over it will result in lower error rates when you play your CDs on the replacement unit! :)
 
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Ah, but how does that affect dipole moment and demagnetization?

jn

It doesn’t.
My question meant to clarify if a possible birefringence due to stress was taken into consideration and screened out before proceeding to electric or magnetic scenarios .

(Birefringence due to stress is used quite frequently for to visualise internal stress flow on components mock-ups)

George
 
It doesn’t.
My question meant to clarify if a possible birefringence due to stress was taken into consideration and screened out before proceeding to electric or magnetic scenarios .

(Birefringence due to stress is used quite frequently for to visualise internal stress flow on components mock-ups)

George

I notice the same long-chain fatty words are used by the folks that cryo-treat CD's.
 
Neil Sinclair gave me the Theta distribution list. At the time I had developed all the optical stuff theta offered with their DACs.

As for the CD's. They are manufactured by a spinning process with the pits pressed . The combination of stress risers and thermal expansion of the polycarbanate create the birefringence. it you twist a piece of translucent plastics you can see the stress when viewing between a pair of polarizers. Old glass blower's trick. What is happening is index of refraction is increasing effecting reflection angle and polarization. Light travels thru any medium by being absorbed and released thru electron states. This mechanism is effected by dipole moments. It is these which are para-magnetic. these moments can hence be manipulated by a magnetic field also. A sort of stress relieving for light.

Inside the CD is like a fish tank. The light, when it hits a "pit" scatters. A good portion does follow the conjugate path back to the photo-detector. The rest gets trapped in the CD bouncing around, hitting other pits and creating a background level of random light. In order for a lens to focus the beam into such a tight spot and such a close distance, it has to have a high numerical aperture (N.A.). The acceptance angle of field of view of the lens is relational to the N.A., in other wards the lens "sees" way more then just the focused spot on the lens. It is more like a photon vacuum. It also captures any light within its acceptance angle.

The spatial filter product was a pseudo one because it did not only filter the first order Gaussian. It was between this and limiting the field of view of the lens mechanically.


What does this mean: Less error correction and less tracking errors, in a nutshell. The magnet trick to a far lessor degree.
 
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Yes, I think that's for a formal, complete review with measurements by JA. Some of the people there like Sam for example, have done reviews of equipment from "internet" manufacturers with no dealers.

From John's essay in the upcoming Linear Audio Vol 8:

'This latter is why I insist that products reviewed in Stereophile that are sold through the conventional retail channel must be available from at least five dealers.'

Jan
 
Well I have to take it your bed never shakes and that may be why you are so grouchy.

Not the case at all. I just don't need a large scale sound system to generate the "perceived intimacy"..

Seatbelts and airbags perhaps...for safety..;)

ps..gave up on the heart rate monitor of course, "overrange" doesn't help much...

BTW, how's it going in your neck of the woods? Summer show up there yet? It's gotta be somewhere?

jn
 
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This mechanism is effected by dipole moments. It is these which are para-magnetic. these moments can hence be manipulated by a magnetic field also. A sort of stress relieving for light.

Paramagnets do not retain any magnetization in the absence of an externally applied magnetic field because thermal motion randomizes the spin orientations.
 
I notice the same long-chain fatty words are used by the folks that cryo-treat CD's.

I heard if you put Mentos in Diet-Coke science has no explanation for the effect.

Now Cryo treat the Diet-Coke and pour it on your favourite speaker.

It will keep the Final Fantasy dragons inside your computer.

Ethernet cable can transfer a CD bit-perfectly in a few seconds, so why don't we use Ethernet wire for speakers.

Harry Potter.
 
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