Hi Ed,
Not secrets really. The secret ones are the ways to come mighty close to all this overkill for a few cents in silicone. And those (though obvious) are not up...
And yes, of course most will not follow up. Heck, most people with a degree in Electronics still believe there is such a thing as Ground...
Ciao T
Not secrets really. The secret ones are the ways to come mighty close to all this overkill for a few cents in silicone. And those (though obvious) are not up...
And yes, of course most will not follow up. Heck, most people with a degree in Electronics still believe there is such a thing as Ground...
Ciao T
I remember such a word in Electric Safety course only, otherwise it was called Общий Провод (literal translation: Common Wire). It imprints under a brainbox deeply that it is a wire that has resistance and inductance, and have capacitive links with all around.
Well it seems I get to tell all the nasty stories.
One of the magazines that shows up here unordered tells the tale of a telephone lineman who while on the pole touched the wire that was supposed to go from the wire strung along the top of the pole neutral lead down to the ground. The grounded neutral on top of the pole is a common technique to reduce lightning damage.
Seems they had changed service from single phase to three phase and the ground wire was disconnected from the top wire as it was now used for high voltage. Well it turned out the ground wire had gotten cut a few feet from the ground. So when he touched the ground wire on the pole, the top arced over to the section he touched. Dead before he hit the real ground.
So ground ain't never ground. Sometimes it could be a lethal mistake. (Wonder what would have happened if some kids even had touched the ground wire above the lower interruption?)
One of the magazines that shows up here unordered tells the tale of a telephone lineman who while on the pole touched the wire that was supposed to go from the wire strung along the top of the pole neutral lead down to the ground. The grounded neutral on top of the pole is a common technique to reduce lightning damage.
Seems they had changed service from single phase to three phase and the ground wire was disconnected from the top wire as it was now used for high voltage. Well it turned out the ground wire had gotten cut a few feet from the ground. So when he touched the ground wire on the pole, the top arced over to the section he touched. Dead before he hit the real ground.
So ground ain't never ground. Sometimes it could be a lethal mistake. (Wonder what would have happened if some kids even had touched the ground wire above the lower interruption?)
If that's noise on a power rail, Ias I have assumed, have to disagree with you.
BTW - That op-amp history also shows that Dick Burwen pioneered the use of inductors across input degeneration resistors, sort of the worst of both worlds in this sense. Not that that is my opinion.
BTW - That op-amp history also shows that Dick Burwen pioneered the use of inductors across input degeneration resistors, sort of the worst of both worlds in this sense. Not that that is my opinion.
Op-amp history reminds me history of Global Economy... Run for parameters that are far from real requirements. Like, eliminating assets to show better profit US companies lost future, the same with ICs for analog audio.
Dick Burwen's hybrid design for ADI is one of the most brilliant innovations I have ever seen. It was the BEGINNING of fully complementary push-pull, now used by Bob Cordell, me, and others. The added inductors were new! They reduced Gm at high frequencies, yet allowed LOW NOISE at working frequencies. Today, all they can use is resistors, which increases the input noise. The late, and competent, Deane Jensen did something similar with his trademark op amp design, that is still made today. Only the change to Toshiba quality input fets allowed the removal of the inductors and retaining the same performance.
In America, at the time, quality, not frugality, was regarded as most important. It may have been different in the URSS.
In America, at the time, quality, not frugality, was regarded as most important. It may have been different in the URSS.
A nice glimpse of the importance of measurements conditions and specifications to distinguish your product from others.
Also a nice example of why 'identical specs' can still sound different.
Of course, the piece is written to promote the company's product but still interesting to read, I feel.
http://www.benchmarkmedia.com/discuss/sites/default/files/Headphone-Amplifier-Performance-Part-1.pdf
jan
Also a nice example of why 'identical specs' can still sound different.
Of course, the piece is written to promote the company's product but still interesting to read, I feel.
http://www.benchmarkmedia.com/discuss/sites/default/files/Headphone-Amplifier-Performance-Part-1.pdf
jan
so what if it has 90 degree phase shift !! It is still conditionally stable and the benefits of negative feedback still apply. The maths don't lie !!
regards
Trevor
I am very sorry but I did not find any trusted measurements in Stereophile, only this short article:
AMR CD-777 Player/Processor | Stereophile.com
Would you mind posting a link to John Atkinson's measurements?
Dick wrote this (from his website)...
"The op amps Dick designed for his own hi-fi system started semiconductor manufacturer, Analog Devices, Inc in 1965."
There weren't any IC's for a while after that, but yes he later switched to them.
Did you ever hear one of these, I would love to see the schematic...
"At Krohn-Hite Corp. Dick designed the laboratory UF101 Ultra-Low distortion Power Amplifier. Using type 6550 output tubes in a multiple-loop,
high-feedback system, this amplifier, rated at 0.005% distortion was manufactured in small quantity for 20 years. "
Last edited:
- Status
- Not open for further replies.