Honestly, I'm not so sure about that.😱
Computer Chips Wired With Nerve Cells - Science News
As an aside. Scott, has the problem in Japan affected the supply chain for the thermoset plastics or glob top normally used in IC production? I shudder to think your guys stick to JIT.
We've a lot of IC's on order for our widgits, so I worry..🙁
On another general note, anybody read the NASA report on unintended acceleration and tin whiskers?
Cheers, John
Here it is. It appears to be an example of a student who knows more (about analogue) than his teacher. A good teacher will rejoice in this. A bad teacher will feel threatened.magnoman said:
JM
Power went off last night due to a storm, so I shut down the experiment. Turning it back on today showed less loss as expected from the inrush current but still more than at the start. So a good idea of what else to check and it may be a small contribution, but the results really do seem to support the slow B/H loop shift.
So why are you on this thread offering reasonable questions politely asked? Haven't you read all the other posts?
John, I think is taking a break because he really takes his longer "teaching" posts seriously. It seems to take him a bit of time with his old guy vision to actually post a few hundred words. So when he hits "Submit Reply" and it fails to appear he gets quite discouraged. (Polite word for really f.. ticked off.)
ES
Why not? All that acrimony seems like it would be exhausting.
Anywayz, it occurs to me that the DC in your input could generate significant DC current in the transformer primary. Could you possibly be saturating the transformer core?
John needs to use the "textedit" app to create his texts then use the apple key + a, then apple key + c and then apple key + v. theat will give him all his text in one go into the message box.
Wrinkle
PS my money is on the transformer saturating.
Ahhh, transformer for line levels. That's what I did a lot some 20+ years ago. I have very good experience with the Lundahl transformers, my favorite Xformers where the LL1524 for line outputs and the LL7101 for line inputs.
If you're concerned about THD, use the 7101 in "balanced zero field" mode, i.e. as a current transformer at virtual ground. And for output transformers, feed 'em with negative output impedance equal to their DC resistance. And if you want to go crazy, add some circuitry to compensate for resistance variation with temperature.
But hey! This is real balanced. Not the ground referenced crap that "high end" audio often uses.... 😀
Ahhh, you young guys...you crack me up..😀
I believe you are correct...
I think Ed mistook my reference to SCR's as "silicon controlled rectifier"...
I believe I gotcha Ed..
Saturable Core Reactor...the first dimmers...
Cheers, John
John,
I saw my first "reactor" in 1970! But the Silicon Controlled Rectifier when used in industrial controls is one of the causes of DC on AC power lines.
Yes I am of the firm OPINION that what is happening with the transformer's loss of output is the low level DC current is slowly moving the center of the BH loop so at one extreme it gets into a more nonlinear edge and reduces the output voltage and increases the distortion.
Since I know the problem actually can happen and how to measure, correct and avoid it, I can move on to other items.
ES
Hmmm..
Knowing the problem...
Measuring the problem...
Correcting the problem...
Avoiding the problem...
That's sounding suspiciously like......
engineering....
Nah, can't be...😕
Cheers, John
There is some concern about starting material, but I don't recall the Sendai area being a big producer. I've been there and felt a small quake getting off the plane, gives one pause. The food specialty is horse sashimi BTW.
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Forum down?
Leave me out of quake territory, I felt a 6.2 on the Big Island of Hawaii and it was terrifying. On a more relevant note, is this forum still functional? Scott's post of the 25th is the last I see...
Howard Hoyt
CE - WXYC-FM 89.3
UNC Chapel Hill
www.wxyc.org
1st on the Internet
Leave me out of quake territory, I felt a 6.2 on the Big Island of Hawaii and it was terrifying. On a more relevant note, is this forum still functional? Scott's post of the 25th is the last I see...
Howard Hoyt
CE - WXYC-FM 89.3
UNC Chapel Hill
www.wxyc.org
1st on the Internet
We're all recovering from the realization that you have gone over to the eight legged side.
Only by necessity, my next two phono preamps will be discrete. Already prototyped. Much more expensive to produce, but lower noise, etc. Similar block diagram.
Jneutron, read the NASA report, they are also doing more testing on lead free assemblies, white papers on IPC site. Finding Tin whiskers on the Toyotas is going to put back any chance of mil/areo/space moving to lead free solders for even longer, this wouldn't be a problem if you could get components with tin/lead finish. The main problem is with BGA devices, these have to be re-balled putting them through a heat cycle before being assembled! When you look at the amount of lead in PCB assemblies (less than 1% before the lentil eaters got their way) and how much effect it had on lead polution, you have to ask yourself whether it is worth the increase in burning fuel (CO2 emmisions) to support the higher reflow termperatures.
We've been studying the feasability of going lead free for several years now, it also is going to effect this 'IPC Printed Board Defense Roadmap – Future Needs of Printed Boards in Department of Defense Electronics Identified by the North American Electronic Interconnect'. It hasn't improved our confidence in lead free reliability, for use in adverse conditions or high rel products.
We've been studying the feasability of going lead free for several years now, it also is going to effect this 'IPC Printed Board Defense Roadmap – Future Needs of Printed Boards in Department of Defense Electronics Identified by the North American Electronic Interconnect'. It hasn't improved our confidence in lead free reliability, for use in adverse conditions or high rel products.
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