Craig Sawyers

Well if you have woofers, you need a meower too. Stands to reason.

That is using magnets in attraction to apply a force to unipivot suspension string, presumably to resist the tendency to wobble. Attraction between magnets is of course stable.

Simple opposing magnets are not stable. The only thing that is stopping this instability is the jewelled bearings - but because of the magnetic instability there is more force on the jewelled bearings to apply a centering force that might be naïvely be expected. I guess that is why the Castagna model A was pretty much the only tone arm to use the magnetic principle. Although at around the same era there was a design and prototype for a parallel tracking arm the used opposing magnets in a saddle arrangement; but that never made it to production. Now it is now possible to levitate stably. The idea being the the repelling magnets are stabilised actively using a set of coils. Around 8cm diameter (so not small) and because of the active control a potential source of electrical interference near to the cartridge. Then there is Meissner effect levitation. That is not entirely daft with high temperature superconductors. Of course it needs the superconductor to be cold enough, so a source of liquid nitrogen is needed. I've done exactly that as a table top experiment when my kids were small, and I was working at Oxford Instruments, so had ready access to chunks HTc superconductor, and a small expanded polystyrene pot for the LN2.

Each of his three marriages has been to a model. The mind boggles.

Happy birthday Andrew, O tall one! Hope it is an awesome one

That absolutely made my day!

That is a hell of good story Steve - I'm massively jealous! We saw Emmy Lou in concert around 6 months ago in Birmingham Symphony Hall (UK). She's 79, and made it clear that was the last time she'd tour outside the US - because of her age she finds it difficult now on endless long hauls. She was superb - lost the clear as a bell high notes, but still absolutely awesome. Back in the late 70's and getting seriously into audio, standard albums that showed off the quality (or not!) of a system was Linda Ronstadt albums. And one of my favourite albums even now is Trio - Dolly Parton, Linda Ronstadt and Emmy Lou Harris - released in 1987 (nearly 40 years ago - eek). Like you said the quality of the harmony and the way their voices complemented each other raises goosebumps. They actually spent well over a decade after the TV show you remember, Steve, trying to follow up with an album. But their personal tour commitments got in the way until Trio was finally recorded.

Carole suffered more angst than me when our kids went to college; Rob to Warwick and Liz to Essex. But the thing to remember when this happens is "Job done". You bring these little creatures into the world totally helpless, they progressively grow up - then they are adults, and quite rightly fly the nest. Now at 41 (Rob) and 37 (Liz) they both keep in touch regularly, and with each other. By phone and WhatsApp. Rob lives in the NE of England, and Liz is on the Gold Coast in Australia with a permanent residence Visa (so she can apply for citizenship). WhatsApp is a wonderful tool.

We did three nice things in London yesterday. Theatre, matinee at the Old Vic. "How the other half loves", a farce by Alan Ayckebourn with a stellar cast including Roger Allam. Absolutely laugh out loud hilarious https://www.oldvictheatre.com/stage/other-half/ Followed by an Indian meal at the famous Cinnamon Club https://cinnamonclub.com/about-us/. Canapes, starters, main course and pudding, two glasses of wine and coffees UK£115 for two. Stunning value for money in London; had to pre-book of course because it fills quickly. If any of you all get to London and like really subtle Indian fine dining - go there. Followed by this https://luminiscence.com/london/ at Westminster Cathedral (Catholic). Narrated (recorded) by Hugh Bonneville and sung live by the renowned Cathedral choir. The cathedral, built in the late 1800's to early 1900's is huge, seating 2000 .

Curiously, the Romans actually mainly spoke Greek. But who can forget "He's not the Messiah, he a very naughty boy!" And:

Although I never saw Dolly Parton in concert, we were lucky enough to see Emmy Lou Harris earlier this year in Birmingham Symphony Hall (UK). At 79, she'd lost her highest notes, but she was absolutely awesome. After a couple of mumbly numbers she said to the sound mixer at the stage side "Can you please rebalance the sound, and bring my voice up" That did the trick!

Well that is a shock for sure. RIP the legend Dolly Parton.

There was a guy on another thread who recently bought some cable from China, and randomly found that a magnet stuck to it. It was iron wire with a thin copper coat. And what a stoopid idea of them using braided cable, and ridiculously short. High capacitance (usually around 50 to 100pF/m, or even more) and very low inductance (sub uH/m). Oh and use the hardback version of Art of Electronics 1.5m would add at least 75 - 150pF!!!

This is a not so funny incident locally around 10-15 years ago, where an elderly lady put the car in reverse instead of forward, and pushed the pedal. Shot back and pinned someone by the legs against a brick wall. Life changing injuries.

Usually nothing wrong with Chinese product, unless you pay top dollar. The actual FOB price will be rather low - which is why most of everything now comes from China. Top UK brand toaster and kettle here are both China made. Goes on and on....

That, good sir, is a thing of beauty!

Happy birthday Todd!

Wow! Really glad you are all safe. Our only brush with destruction on that scale in the UK was the hurricane that supposedly wasn't. On the BBC weather forecaster called Michael Fish said: "A few hours before the Great Storm of 1987 broke, on 15 October 1987, Fish said during a televised weather forecast: "Earlier on today, apparently, a woman rang the BBC and said she heard there was a hurricane on the way. Well, if you're watching, don't worry, there isn't!" When it hit, the severity of the storm, which was in fact the worst to hit South East England for three centuries, caused record damage and killed 19 people. From Wikipedia https://en.wikipedia.org/wiki/Michael_Fish

Yes I know. But it is nonetheless exceptionally persuasive. There is a time oddity though. The AI Feynman talks about dark matter (which was around as a measured thing well before he died) and Dark Energy, which postdated his death. I'd clearly forgotten that Feynman died aged 69 (from cancer). Reputedly his last words were "This dying is boring"

Here's a fascinating (at least to me) series of lectures by one of my heroes - Richard Feynman. These are all about an hour long, and I was enjoying his engaging talks about diverse topics. For example, below. You get a flash at the beginning that I missed. But at the bottom it is Feynman Reborn, an AI Feynman, along with unmistakably his voice. There is a list of publications at the bottom (for example the Feynman Lectures on Physics). There is a series of these, and the only real hint that something is up is if you look at the background. I think that the authors of the AI Feynman left a really weird background to give a sense of the unreality of the superb AI Feynman.

I can't believe I'm going to bore you all about Newton. Although English, he wrote Principia and Optiks in Latin. An that is a real problem - translating back into English is a tickly thing, particularly the more fundamental stuff which is to do with what we learn as Newtons laws of motion at school. What is the precise translation of momentum for example? After that the translators have an easier job. Newton derived all his proofs in his long book Principia geometrically, step by step. He finishes off by meticulous measurements of the motion of the planets etc. At one stage he says that a chunk of the measurements was lost, but he can recall the basic idea behind the measurement. By "lost" he actually meant that his dog ate some of the sheets, or knocked a candle over and set fire to some sheets. Accounts vary. As professor at Cambridge University, his lecture course was so unpopular that no students attended. But part of his job was to give lectures. So he'd turn up and give the lecture to an empty theatre. In later life he spent most of his time studying alchemy. I'll shut up now

Sam Neill RIP. Aged 78 BBC NewsSam Neill, Jurassic Park and Peaky Blinders actor, dies a...The New Zealand actor, who was born in Northern Ireland, died in Sydney. He had recovered from cancer and "the loss was sudden and unexpected", his family says.

Ex conservative politician, recently defected to Farage's party dictatorship Reform, Ann Widdecombe, 78, was murdered in her own home a few days ago. A 28 year old white male has been arrested. Not extremist, not political - so it is currently unknown why he did it. https://en.wikipedia.org/wiki/Ann_Widdecombe RIP

That is a great loss. RIP David Hockney.

The Russia/Ukraine war just passed a milestone of running for longer than WW1