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Friday, 16 June 2023

99A Charing Cross Road

 


I never realised just how Art Deco that building is above the shop level. Did they clean the exterior during the lockdown?

Tuesday, 13 June 2023

Why Les Paul Volume Controls Affect Both Pickups When Selector Is In Middle Position

The Les Paul has two pickups, each of which have their own volume and tone controls. The iconic selector switch is at the upper segment of the body and has three positions: Treble (down) for the Bridge pickup, Rhythm (up) for the Neck pickup, and middle which uses both pickups.

With the switch set for the Neck pickup, the Bridge controls have no effect on the sound - as you would expect. With the switch set for the Bridge pickup, the Neck controls have no effect on the sound. Put the switch in the middle, and turning either volume control down to about 1 or lower shuts off the signal from both pickups, no matter how loud the other one is set to.

Wha? Huh? Is it broken? No. It's a feature. (Which I spent the better part of a Sunday understanding.)

FACT ZERO: the pickup-> volume control -> tone control -> selector switch circuits are wired in parallel.

FACT ONE: The volume controls are potentiometers, not variable resistors. A potentiometer has three tabs: input, output (attached to the variable control) and ground return. A variable resistor has two tabs: input and output. This matters. Were we to put a current in via the output tab (sounds odd, but no harm will result), a potentiometer provides two circuits: one to the input tab, and one to the ground return tab. Each one of those has a resistance: Rin and Rgnd, and Rin + Rgnd = 500k ohms always, at least on Les Pauls.

This will be important in a couple of paragraphs.

FACT TWO: don't forget the most important circuit in any guitar, the one out to the pre-amp, which takes a louder copy (that's what amplifiers do), and lets the original current go back into the guitar return circuit. That amplifier circuit has a resistance, Ramp.

Back to the Selector Switch. When it is in the centre, both output lines are connected.

Read that again!

When the switch is in the centre, both the output wires from the volume controls are connected. The output tab of the Neck pickup is connected to the output tab of the Bridge pickup.

So by facts ONE and TWO, the output tab of each volume control sees three circuits:

1) to the amplifier, resistance Ramp

2) to the other volume control and out through the ground return, resistance Rgnd

3) to the other volume control and out through the input tab, resistance Rin

This is where the magic happens. As we turn down (say) the Bridge volume, we are increasing Rin and therefore decreasing Rgnd because that's what happens in a potentiometer. Keep turning the volume on the Bridge down, and Rgnd will become close to and then much lower than Ramp. At which point hardly any current is going to the amplifier, because it is following the path of least resistance, Rgnd, and the guitar sounds as if it's been turned off.

Which was required to be proved.

This does not happen with Strats and Teles because the selector switch is before the pots in a Fender, and the connection to the pots is made by the same wires from the switch frame, no matter what position the switch is in.

(Some gnarled old electrical engineer at Gibson no doubt took one look at the mock-up of the Les Paul circuitry and said "Very nice, if you want one pot to ground through the other at low volume when the switch is in the middle." And everyone shook their heads and thought, there goes Old Joe again. Until it happened.)

Friday, 9 June 2023

Sunny Day - Mystery Location

 Where is this quiet bucolic place in the countryside? A little hint of Victorian brickwork, some modern lights, and a single-track railway. 



Highlight below to see the answer.

Crystal Palace

Tuesday, 6 June 2023

Johns Hopkins University on the UK Lockdown

Prof Steve Hanke from Johns Hopkins University, in the US, Dr Lars Jonung, from Lund University, Sweden, and Jonas Herby, special adviser at the Centre for Political Studies (CEPOS), recently completed a study that showed, to exactly no-one's surprise, that during the first wave of the pandemic (March - June 2020, but they don't say specifically) 1,700 lives were saved buy the lockdown measures. They say that Government-imposed lockdowns were un-necessary, because people would have adjusted their behaviour.

In other words, the Government didn't need to impose a lockdown, because the people would have imposed their own. This was pretty much what happened in Sweden.

Sweden, by the way, has one million more people (10m) in it than London (9m). The UK has 63m people. One of those countries is not like the other.

What would have been the economic damage of leaving the people to decide for themselves, but with Local Government continuing to charge the Business Rate, and landlords continuing to charge rent? It does not take much of a loss of business before a cafe or cinema can't pay rent and business rates, and it does not take much more before the balliffs or the bank come thundering in. Railways must run, or trees will grow through the tracks, so public transport would have needed subsidising. I don't know what the numbers would look like, but I do know that much of the economic activity in the UK relies on low wages, debt, and overdrafts.

What happens if a nurse decides she doesn't "feel safe" going in for her shift? Or a policeman? Or a supermarket lorry driver? Or a sewage plant maintenance man? Or the people who run your local pharmacy? Would employers be able to sack workers who "didn't feel safe"? With every other Government in the world telling people there's a killer virus on the loose? Even if employers could "hibernate" concerned workers, who would replace them? Would businesses lay off people in anticipation of a loss of income? And what do those people do for money, since employment has dropped?

You can feel the chaos already.

But... divide the workforce into two, with "non-esssential" workers forced to "work from home", and the "essential" workers are, by contrast, required to show up at the hospital, depot, supermarket, bus garage, sewage plant, power station, and so on. Declare an emergency and Councils can be made to hold back on the Business Rate, landlords on rents (some of the better ones, not the De Walden Estate), while furlough can be paid to keep people in money...

The correct comparison is what the figures would have been if the UK had carried on as usual, with white-collar workers adopting in-the-office schedules and working from home otherwise. Businesses, shops, cafes, restaurants, gyms, swimming pools, cinemas, theatres, and the like all open as usual. No restrictions. Anyone who gets the symptoms, stays home for five days. (We should be doing that anyway!) The Government makes it clear that: a) you cannot sue anyone if you caught the Virus on their premises; b) you will be sent to Re-Education HR for an "assessment" if you claim to be that scared of getting what is actually a bad case of the flu that almost everyone will survive.

And someone would have needed to shut those whining, hand-wringing journalists up. Let's not forget, it was Piers f******g Morgan who bullied the Prime Minister into making the Police enforce lockdown, which the Police did not want to do.

My guess is that even a part-time working-from-home / office regime would hit the town-centre businesses the same way it has now, a lot of marginal business would still have closed, and many managements would have used the opportunity to rationalise.

If the Virus had struck in 2010, nobody would have been working at home, because the internet / broadband infrastructure was just not good enough. But in 2010, people still had their own desks in the open-plan offices, and more space around them, compared to the crammed offices of 2019, so they would not have adopted working from home with the same enthusiasm. A curfew on social life would have been impossible to justify: if it's not safe to go to the movies, it's not safe to go to work. Maybe some restrictions on the number of people in social spaces could have been imposed. We would have worn masks in public spaces (but not offices), but not as a badge of our virtuous compliance, but as a nuisance just to keep the b****y Government happy. A lot more people would have had a bad few days, and then enjoyed subsequent immunity. The kids would have stayed at school. Families would have been able to see each other, and attend funerals and weddings as they should.

We cannot use the Swedish figures as a proxy for "no lockdown" because the Swedes put themselves into a self-imposed lockdown and the population density is lower. What we do know is that almost nobody died solely from the Virus: they died - often painfully and tragically - because they had other conditions, and the Virus was one too many. This was known from the start. Because of that, the additional deaths would have been smaller. In fact, from what we know already, if the transfer of older people into care homes had been done with the slightest bit of care, there may have been fewer deaths.

Friday, 2 June 2023

Deep In Epping Forest


 About halfway round the Holly Trail there's an area of what may be marshland if it gets wet. They don't want you riding horses over it. This scene is part of that. Heaven knows where the water comes from: the area around it is bone-dry.

Tuesday, 30 May 2023

How To Translate Faraday's Law of Induction into Math

I know what you're thinking. What does he get up to that stops him posting promptly and prolifically? I wish it had something to do with Instagram models and / or  staying up late making music via Garageband, but it is much more mundane than that. Here's a short passage about the translation of Faraday's Law of Induction into mathematical notation that I've been working on for far longer than you might think. If I've done my job well, it should seem obvious. (Some of the original \LaTeX has been butchered to accommodate Blogger.

(starts)

Faraday's Law, more or less as stated by Faraday, is: the electromotive force around a closed path is equal to the negative of the time rate of change of the magnetic flux enclosed by the path. How does this get translated into mathematical notation? We need to know that the `electromotive force' is, in the case of magnetic induction, the work done on an elementary electric charge (such as an electron) travelling once around the loop. Work done moving along a path is always a line integral of the product of a force and a displacement (since `work = force times distance').

As a first step, we re-name those things as variables or constants:

let $\mathcal{E}$ be the electromotive force

let $B$ be the magnetic flux

let $\partial A$ be the path, enclosing an surface A

let $ds$ be a small displacement along $\partial A$

let $E$ be an electric flux field

We can write down the equations quite easily if we are familiar with the vector calculus. Work done is given by the mantra `work = force times distance'. For a small displacement $ds = (dx, dy, dz)$ and a force $E = (E_x, E_y, E_z)$ the product is $E_x dx + E_y dy + E_z dz$ which is $E \cdot ds$ in vector notation. The work done along a line is the sum of such displacements along it, which is conventionally shown by the integral $\oint_{\partial A} E \cdot ds$, giving us $\mathcal{E} = \oint_{\partial A} E \cdot ds$.

Translating the other side of Faraday's Law, Faraday thought of electromagnetic fields as `lines of force' - the more lines, the more force - and the flux of a field through an area was the number of lines of force through it. This was Faraday's way of thinking about line and surface integrals without having to actually use either. 

The number of lines of force within a path is the integral of the (strength of the) vector field over any smooth surface enclosed by that path. (The `any' has to be proved, but it is becomes intuitively obvious after visualising a few examples.) So if we take a surface $A$, divide it into non-overlapping patches $dA(n)$, calculate $\frac{\partial B}{\partial t}(n)$ for the centre of the $n$-th patch, and add the total, we get an estimate of the electromagnetic field strength. Make the patches smaller, and we get a better estimate, which in the limit is the integral 

$\mathcal{E} = -\iint_{A} \frac{\partial B}{\partial t} \cdot dA$

That can also be turned into a conventional double integral by substituting coordinates. Hence Faraday's Law of Induction is translated into mathematical notation as

$ \oint_{\partial A} E \cdot ds = -\iint_{A} \frac{\partial B}{\partial t} \cdot dA$

The left-hand side is the work done, and the right hand side is the negative of the time rate of change of the magnetic flux enclosed by the path. This completes the translation of Faraday's Law into mathematical notation.

This is no more conceptually complicated than if we had translated, say, a passage of Freud from German to English. There is no word-for-word mapping of the two languages, and there are many concepts for which there is a German word, but not an English one, and one must attempt to explain the German concept in English. Using an integral to denote the result of a limit of finite sums is no more exceptional that using a derivative to denote the result of take rates-of-change over ever small intervals. 

We can use some maths to go further. By Green's theorem, assuming the fields are sufficiently smooth, we have

$\oint_{\partial A} E \cdot ds = \iint_A \nabla \times E \cdot dA$

So we can put

$\iint_A \nabla \times E \cdot dA = -\iint_A \frac{\partial B}{\partial t} \cdot dA$

which gives us immediately one of Maxwell's equations

$\nabla \times E = -\frac{\partial B}{\partial t}$

We can prove that, with the rest of Maxwell's equations, this another statement of Faraday's Law of Induction. 

This is no more conceptually complicated than if, having translated the passage of Freud, we then drew a conclusion from the translation and some background knowledge that was not in the original, but helps us understand what Freud was saying. It just looks impressive / mysterious / difficult because it uses undergraduate maths.

(ends)

My thesis is that translating from a natural language into math notation is the same as translating from one natural language to another. It's just that maths is the language in which it is easier to see the patterns and make the deductions.

Tuesday, 23 May 2023

"Good People" As Useful Idiots

Throughout history groups of people have wanted to identify each other, and to feel superior to everyone else. That's what the "Shibboleth" story (Judges 12:5-6) is about. Not only must the Bad People find it almost impossible not to betray themselves almost immediately, but it must be difficult for the Bad People to turn into Good People.

Good People usually work in the public sector, broadly construed as any occupation financed almost completely by the taxpayer. NHS, universities, schools, the Armed Forces, the Emergency Services, BBC, local council staff and officials, and publicly-funded arts organisations. It's about a third of the UK workforce. It's not everyone in the public sector. Good People are usually managers rather than doers, and policy-oriented rather than operational. They see themselves as being funded by the Government, and prefer political parties that hand out money, which has usually been the "left-wing" parties. They loved the EU, because of its generous grants, hence their existential panic over Brexit.

Their education stressed going along with the prevailing group-think, which can happen in the Science Faculty (think "Climate Science") as well as the Arts. They are usually not engineers or researchers whose work can be disqualified by an experiment. Good People often believe in "experts" rather than "facts" and "experience", not least out of collegial courtesy, since many of them are "experts". This makes Good People sitting targets for frauds, grifters, marketing departments, visionaries, snake-oil salesmen, and pseudo-scientists.

A qualifying Good Belief must meet a number of criteria: it must work against the interests or beliefs of regular people; it must have a very low probability of ever being turned into legislation; and it is must have a very low probability of Capital ever turning into a profitable product or service; and it must not be detrimental to the Good Person. Also, it helps if it is more expensive than the mainstream alternative.

Refusing to use modern medicine is not a Good Person belief, since it can cause harm to the Good Person. Veganism is a Good Person belief, as is keeping kosher. World Peace is not a Good Person belief, because who doesn't want that?

Being "for" homosexuality was a Good Belief. It had resisted changes in legislation for hundreds of years; it is not well-regarded by the common herd; even after the 1967 legislation, Capital has been hesitant to aim products at the Gay market, partly because it is too small to support major spending; and of course, if the Good Person was gay, it was a bonus, and if they were straight, it didn't matter. Until their children came out. By the 2010's the Police across the world were happily taking part in Pride marches, as were lots straight people and politicians. Homosexuality is now nothing remarkable.

Which was an utter disaster for the Good People. For about five decades, the Good People had been able to distinguish themselves by professing a belief that homosexuality should be nothing remarkable. And now the Bad People agree. Which means the Good People needed to find some other cause to distinguish themselves. If that cause was going to be around sexuality, it was going to be pretty far out. And it turned out to be just that.

Climate Change had some things going for it. The facts are iffy as heck, which means that one must believe. Bad People want facts, Good People are Believers. Nothing bad was going to happen because of Climate Change (if was real) in the short-term: climate disaster has been ten years away for the last thirty years. For a couple of decades after the start, there was no hope of it turning into legislation, there were no serious alternative energy sources, and few demands on individuals' behaviour.

Having baited the Good People, the Climate Change con-men pulled the switch. They continued to press for legislation from whichever body might find it a constructive-looking gesture. They let the investment banks in by inventing so-called "carbon offsets". They persuaded Governments to subsidise wind farms, which made alt-energy a better investment. Nobody ever pushed the "energy security" issue, because that smacked too much of Nationalism, and Good People are not Nationalists, but energy security (from the increasingly volatile Middle East) was the unspoken benefit of all this. The con-men flooded the culture with pseudo-science, graphs compiled by methods so dodgy as to make political polls look honest, and frequently-published forecasts of possible disaster and death. The Good People found they had been suborned into a full-fledged activist movement, and it took a few years for them to disassociate themselves from it. People who use phrases like "climate emergency" sound like the cranks they are. Sadly, that crankishness has been embedded into Government policy, and it will take our politicians a while to extricate themselves from it.

"Diversity" is a Good Person belief. They are insulated from it by their postcodes and occupations, and by the fact that Good People are inter-nationally the same. The legislation had long been in place, it cannot be turned into a product or service, and it provided a lot of cheap labour, often to look after Good Children. Furthermore, "diversity" could mean that one's wife was now up for a lucrative part-time Directorship. In the meantime, "diverse" neighbourhoods and organisations have much lower levels of social trust, participation, co-operation and communication. Crime figures are carefully never printed or discussed. It was hi-jacked by a number of interest groups, all of whom measured it by looking at outcomes, while simultaneously denying they were imposing quotas.

"Being nice to illegal immigrants" was briefly a Good Cause in 2016. The Economist - the reference Good Person source - even suggested that a million people was not so many given the population of Europe, and we could absorb them. It never occurred to the witless writer that there were several hundreds more of those millions in the queue. Women in Germany and Sweden felt guilty about having to explain that the men who molested or raped them were, well, not native Swedes. The official obfuscation of the crime figures was driven by one thing: the incumbent Governments were all left-wing socialists, and they were terrified that the right-wing would get support if the truth was made public. Also, the fact that these immigrants seemed to have the phone numbers of lawyers, and detailed instructions about the welfare payments they could get, and of the European rail system, started to seem a little odd.

The immigrants had NGOs helping them, and those NGOs needed money. That money did not come from millions of donors, but from a handful of wealthy activists who have more money than they will ever need, and are looking for elite social recognition, which they get through backing Good Causes. The emergence of that class was something new in the 2000's: there had been rich people before, but they used their wealth to help themselves, even when founding institutions in their names. The new class did not want popular publicity and recognition, but only to belong to an elite. They did not elderly men and women gluing themselves to the M25: they did it through PR companies, NGOs, and lawyers who realised there was a nice living to be made pandering to them. Small in number, these are the most dangerous kind of Good People, as they can and have inflicted huge amounts of harm on ordinary people.

Illegal immigration in the USA is a large-scale political grift: the main beneficiaries are some large religious organisations who are paid to place illegal immigrants, and they do so because the Democratic party uses the immigrants to jerrymander voting districts. It is hidden, badly, behind the facade of a Good Cause, which is used by Democrats to pose as morally virtuous. Good Causes are now often hi-jacked for very different purposes.

Capital has been hi-jacking Good Causes since the start: Good People make up a decent-sized, high-margin market segment. Electric cars. Fake meat. Green electricity. The Whole Foods chain. Feminism was hi-jacked to get women into the workforce (notice how they got the jobs, but never the creches that the original feminists were asking for). MeToo was hi-jacked by managements and used to remove people - usually older white men - from their jobs or contracts on a mere allegation. ESG / DIE scores were invented specifically to whitewash the activities of hedge funds and investment banks. In return it was exploited by the certifying agencies, who realised they could push extremist agendas, and the hedge funds simply would not care.

The ability of Capital to react at speed does not help: no sooner does a cause become Good than marketing departments start to think about how they can hi-jack the cause reflect their customers' concerns in their products and messaging. Those marketing departments are often full of Good People who see themselves as furthering the cause. And hey, if they can get a promotion out of it, that's a win-win. After all virtuous consumption is the easiest virtue of them all.