Every single time I have to explain a math problem to an A-level highschool (for Master's admission, not Bachelor) twit* here, I wonder why mathematics is not taught differently at pre-college/university level, with some extras.
E.g. dimension analysis, very useful tool, and easy to understand by under 18's.
First couple of years at university was loaded with math, after about a year of partial differential equations, multiple integrals, Jacobians and various theorums/operators, applied to areas as heat/fluids/materials/mechanics/sound/electricity, I had these moments of epiphany, as like the entire universe opened up.
My neighbor two houses down the road got his masters at the same faculty, also in ship design & maritime business.
Is managing head for projects and QA/QC at the Shell HQ in The Hague now, but started out calculating stuff as e.g. flexible risers on floating production systems and gravity launched life boats at the Shell research laboratory in the mid '80s.
Couple of months ago, he told me that his younger collegues can't hack that stuff. Everytime something comes up, which involves heavy duty math, he has a couple of weeks off-time from his regular job.
(Wil Boef, example, ANALYSIS OF A FLEXIBLE-RISER TOP CONNECTION WITH BEND RESTRICTOR - Transport Research International Documentation - TRID)
* mathematical retard & full-time internet gamer idiot has finals in 5 weeks from now, fortunately decided to go for air-traffic controller instead of poly-u. Fingers crossed, would leave just one hiney to boot-out before freedom. Pardon my Hick.
(die werelt, si es vol dwaalman : Die droom van 'n belaglike man (The dream of a ridiculous man). - Free Online Library )
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Perhaps, but noises of crinkling cellophane could conceivably be distinguished, if only at a subconscious level. I'd suppose that other easily-measured effects like frequency response would likely be the major distinguishing features affecting preferences among trafos for low-level stepup.
The same audiophile who decided that an entry-level phono pre should have a JFET pre-pre for MC cited his dislike of anything other than very prohibitively 'spensive transformers. I don't know if he listened to the Sowters (still too expensive) but he did mention his favorite preamp being a single battery-powered 2SK170 with a load resistor and presumably a output coupling capacitor. He has a penchant for simplicity above all else, and a deep distrust of anything that looks complicated, which makes it a wonder that I worked for very long with him at all.
When he asked me what could be wrong with his simple preamp, I forget how many things I recited, but I know I couldn't manage it on one deep breath.
Yes. It was taught to 17-year-olds in A-level physics in the UK in the 1970's. I don't know if it is still taught. Very useful tool.
When are you Yanks going to start using the SI system? Then you can ditch your phuctuns.
I had to learn about rods and perches in school at first, but by the time I left it was all Kg and metres. I still bought petrol in gallons, though, and was restricted to 30mph in town.
I had to learn about rods and perches in school at first, but by the time I left it was all Kg and metres. I still bought petrol in gallons, though, and was restricted to 30mph in town.
There was something rather wonderful about the ludicrous complexities of the imperial measurement system and Lsd ( for non Brits Lsd = "librae, solidi, denarii" = pounds shillings & pence )
In any technology field, we already do. Most scientists/engineers are bilingual.
I can attest that every teenager I grew up with knew how many grams there were in an ounce.
It would be better to suggest AC bias 😎
Heads for wire magnetophones and steel tapes were initially dc biased. Then by accident, thanks to a head amplifier that developed oscillation while recording, a gifted engineer noticed the improvement ac bias caused, optimised it and … all this before WW2
George
I never cease to be amazed at the discussion here. DC in transformers? Barkhausen noise? Low level low frequency distortion? Shot noise?
Has anybody studied these things? I don't know where to start.
Has anybody studied these things? I don't know where to start.
Hi John,
Based on listening evaluation (rather than only measurements), it seems to me that with tube-based line level amps and phono stages, between capacitor and transformer at the output, transformers are the lesser evil, provided they are really good ones.
As for MC input, I doubt if there is any really good transformer. Possibly a JFET cascoded by a tube would be best. I'm going to try it.
Based on listening evaluation (rather than only measurements), it seems to me that with tube-based line level amps and phono stages, between capacitor and transformer at the output, transformers are the lesser evil, provided they are really good ones.
As for MC input, I doubt if there is any really good transformer. Possibly a JFET cascoded by a tube would be best. I'm going to try it.
Speaking of books and job interviews, here's one worth reading:
The No ******* Rule: Building a Civilized Workplace and Surviving One That Isn't: Robert I. Sutton: 9780446698207: Amazon.com: Books
The No ******* Rule: Building a Civilized Workplace and Surviving One That Isn't: Robert I. Sutton: 9780446698207: Amazon.com: Books
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I think Whitlock's chapter in Ballou's book is a very good place to start.
http://jensentransformers.com/an/Audio Transformers Chapter.pdf
se
And thanks in part to my efforts, some of my friends knew it to four significant figures. However we learned that a number of shifty characters with whom we were sometimes left to deal considered that 25 was plenty for street transactions, and there was a distinctly politically-incorrect term for such an "ounce".
"Those days are gone..." Wait --- I'm repeating myself again. Goes to show.
Know Thine Enemy.....
Snakes in Suits: When Psychopaths Go to Work: Paul Babiak, Robert D. Hare: 9780061147890: Amazon.com: Books
Dan.
Here's another... Review - Snakes in Suits - The Australian
Snakes in Suits: When Psychopaths Go to Work: Paul Babiak, Robert D. Hare: 9780061147890: Amazon.com: Books
Dan.
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The late Allen Wright describes one thus in his Tube Preamp Cookbook. As I recall, about the only problem i noticed was his assumption that the load presented to the JFET drain by the common-grid tube is sufficiently low impedance, and the transconductance of the JFET sufficiently high, even when he's going for maximum gain out of the circuit presented. I have forgotten what the parts were, but I think I know where the book is in storage.
He was kind enough to sell me one of his last copies some years ago, and waxed rhapsodically about the degrees of freedom one would surely have at a big company like my then-client Harman. I was rather sad to tell him this was illusory, at least for them.
Well, I got away with my comments. Now, everyone, what did I mean with the previous comment that I made? Please understand that I only want to help.
That's a very good article in a rather uneven edition of that book. I particularly appreciate his section about telephone "hybrids", which can be difficult to find and are immensely clever circuits. As so many nowadays are eschewing land lines and have little experience with full duplex telephony, the knowledge will likely become increasingly arcane.
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