OFF TOPIC:
PHN,
I don't know where you live... but I live in a world where unscientific sectarian beliefs, an impending energy shortage, and a planet populated like so much agar in a petri dish might soon bring out the worst in all of us. I am largely prepared for it. Oil is on its way out. Alcohol, tobacco. and firearms may be our next global currency... I really hope not.
I can't reply further without violation of the "politics" rule...
Where's Kofi dammit?
PHN,
I don't know where you live... but I live in a world where unscientific sectarian beliefs, an impending energy shortage, and a planet populated like so much agar in a petri dish might soon bring out the worst in all of us. I am largely prepared for it. Oil is on its way out. Alcohol, tobacco. and firearms may be our next global currency... I really hope not.
I can't reply further without violation of the "politics" rule...
Where's Kofi dammit?
Chris,
I gather you're up on the technology as well... good man... Canada boy... go figure! "Berkeley glue"... good one!
John,
You didn't notice Quasi's fuse artifact from the depths of antarctica? The ancients had charlatans too.
SY,
I am cooking "jerk chicken" that has been marinating for a day or two for my 4000 girls... this with raw cabbage and a fresh fruit salad. Just for fun, I am hiding the milk.
I gather you're up on the technology as well... good man... Canada boy... go figure! "Berkeley glue"... good one!
John,
You didn't notice Quasi's fuse artifact from the depths of antarctica? The ancients had charlatans too.
SY,
I am cooking "jerk chicken" that has been marinating for a day or two for my 4000 girls... this with raw cabbage and a fresh fruit salad. Just for fun, I am hiding the milk.
Many comments...
Rifle barrels-
Stuff that is done for competition is often as much about giving the competitor a psychological boost as actually doing something objectively beneficial. Bike racers fill their tires with helium, target shooters cryo treat their barrels even though the manufacturer says it will have no effect. If the competitior believes it has an effect, it will improve his mental condition for the competition.
Resonances-
This word should trigger your marketing BS detector and send you running in the opposite direction. It is such a meaningless bit of nonsense you should laugh in the face on anyone (except maybe a physicist) you hear uttering it. It's equivalent to explaining how it works because it is Tuesday and the moon is a waning crescent. 99.99% of everyone who uses the term to explain anything does not know what they are talking about. How do you find the 0.01% who do? That's easy. They are the ones who aren't trying to get at your wallet.
A/B testing a cryo'd amp-
If you're going to compare two circuits they should be the same except for the cryo treatment. You'll have to use conductive epoxy for both amps, not just the cryo'd one or you won't know if the "improvement" you are hearing is due to the cryo treatment or the epoxy or the combination of the two.
"But you cannot discard millions of people as wackos because of their beliefs." Any exception made for Naziism? How about "intelligent design"? How about the Khmer Rouge? What about electing W not once, but twice? What about all those alien abductions and anal probes? Yes, the masses are certainly in tune with good sense and reason...
Now if you'll excuse me, I have a book-burning to attend. Tonight's menu includes a first edition copy of Charles Darwin's "The Origin of Species". It promises to be a real crowd pleaser!
I_F
Rifle barrels-
Stuff that is done for competition is often as much about giving the competitor a psychological boost as actually doing something objectively beneficial. Bike racers fill their tires with helium, target shooters cryo treat their barrels even though the manufacturer says it will have no effect. If the competitior believes it has an effect, it will improve his mental condition for the competition.
Resonances-
This word should trigger your marketing BS detector and send you running in the opposite direction. It is such a meaningless bit of nonsense you should laugh in the face on anyone (except maybe a physicist) you hear uttering it. It's equivalent to explaining how it works because it is Tuesday and the moon is a waning crescent. 99.99% of everyone who uses the term to explain anything does not know what they are talking about. How do you find the 0.01% who do? That's easy. They are the ones who aren't trying to get at your wallet.
A/B testing a cryo'd amp-
If you're going to compare two circuits they should be the same except for the cryo treatment. You'll have to use conductive epoxy for both amps, not just the cryo'd one or you won't know if the "improvement" you are hearing is due to the cryo treatment or the epoxy or the combination of the two.
"But you cannot discard millions of people as wackos because of their beliefs." Any exception made for Naziism? How about "intelligent design"? How about the Khmer Rouge? What about electing W not once, but twice? What about all those alien abductions and anal probes? Yes, the masses are certainly in tune with good sense and reason...
Now if you'll excuse me, I have a book-burning to attend. Tonight's menu includes a first edition copy of Charles Darwin's "The Origin of Species". It promises to be a real crowd pleaser!
I_F
Post removed here due to violation of forum courtesy rules. Calling a thread participant a fool is not acceptable in this bar and grill.
Re: Re: Re: REAL cryogenics
But making up scientific explanations and pushing them as reality, that is not acceptable.
You need to find some text that explains the inhomogeneity of the mass structure, the current redistribution, and the resultant end effects. I'll give you fair warning...you will find nothing in existing literature which details that. There may be some EMP work which considers this problem, but that will not be accessible by you, there is a little bit of HTS work which starts to think about this, but not much else..
We've had some issues with the helium freezing leftover nitrogen, bolluxing the system to where we have to warm up to 80K or so to pump down the gas.
Hmmm..ah,,,,some old guy...who just loves Jackson..
Cheers, John
From a measurement point of view, yes I do. I find it has been especially difficult attempting to explain it to audio types, as the end concept requires far too much up front homework, without entertaining the mathematics at all, just the concepts.john curl said:
But making up scientific explanations and pushing them as reality, that is not acceptable.
While relevent to something, it certainly is not applicable to the discussion at hand.john curl said:
You need to find some text that explains the inhomogeneity of the mass structure, the current redistribution, and the resultant end effects. I'll give you fair warning...you will find nothing in existing literature which details that. There may be some EMP work which considers this problem, but that will not be accessible by you, there is a little bit of HTS work which starts to think about this, but not much else..
It is very cost effective to use ln2 to get down to 77K, the helium is so expensive. That way, the helium only has to get the stuff down to about 50K, where the heat capacity darn near vanishes.Bratislav said:
My guess is because instrument will be at room temp, it is quick and cheap to precool it with LN. Both He and N tanks are emptied before LHe is applied, and then only LN dewar refilled, so no chunks of nitrogens result after LHe is flown in (unfortunately! it'be fun to throw some nitroballs
We've had some issues with the helium freezing leftover nitrogen, bolluxing the system to where we have to warm up to 80K or so to pump down the gas.
SY said:
Hmmm..ah,,,,some old guy...who just loves Jackson..
Cheers, John
poobah said:
Copper:16 ppm/C
Aluminum: 25.5
silicon: 3.3 (temp dependent) (718/(T + 173))
silver 19.6
Molybdenum 5.1
gold 14.16
germanium 6.1
beryllium 11.5
lead/tin solder 25
Gold/Ge 13.35
Gold/silicon 12.33
Alumina about 7
Stycast 2850: 29 below alpha, 90 above.
The die attach solidifies at a high temp, as it cools, it builds up residual stresses. At room, it has a shear stress. Over time, this stress will lower if the die attach is with a ductile alloy.
Cryo may force the issue of stress reduction, but may also compromise the die attach.
Transistors will changer parameter if the die attach stress is lowered, but that is an easy thing to test. I suspect the first thing to be altered will be secondary breakdown of bipolars, with some small, probably not measureable, increase of thermal resistance.
Large epoxy units typically use a matched expansion epoxy to lower tce issues. They also choose glass transitions above operating temperatures, as softening is not good, nor is the rapid expansion above it.
Cheers, John
I have not recommended cryoing whole electronic assemblies, mostly because of dissimilar expansion coefficients. In fact, I once threatened to void the guarantee of a CTC preamp on this account, if they damaged it by putting it through a professional cryo process. So far, some caps, heatshrink, some plastics, and a few other parts that either have air or water 'pockets' seem to be badly effected by cryoing. Virtually everything else, including CD's, guns, pistons, Bybee devices (raw state), circuit boards, etc come through OK.
Is it useful? Some say yes, others say no, and still others think that they know that it doesn't do anything, without trying it.
"Condemnation without examination, is prejudice"
Now where did I hear that before?
Is it useful? Some say yes, others say no, and still others think that they know that it doesn't do anything, without trying it.
"Condemnation without examination, is prejudice"
Now where did I hear that before?
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