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Everything posted by Craig Sawyers
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The Knuckledragger 3rd Memorial Slow Forum Post
Craig Sawyers replied to Knuckledragger's topic in Off Topic
^WTF who would even think that was a good idea - hey let's dice with death today and see if I get away with it -
I haven't looked at USB in detail, but this piqued my interest. Turns out that the characteristic impedance of USB cable, and termination resistance at send and receive end is surprisingly loosely defined, but nominally 90 ohms differential or 45 ohms single ended for USB2. Depending on what web document you are looking at these can be +/- 15%. The isolators provide galvanic isolation (using a pulse transformer), which is a good thing. SPDIF links usually have galvanic isolation at both send and receive ends - usually poorly implemented, but that is another discussion. Generally galvanic isolation reduces jitter through reducing common mode noise. There are some interesting measurements of this here http://www.scientificonversion.com/ The regenerators try to compensate for poorly implemented send impedance by providing proper termination and send impedances, nicely implemented, and using a high(er) quality local clock. That these make a difference (and I believe that they do) is really down to poor implementation (impedances and noise) at the send end - the computer - and potentially poorly implemented receive end at the audio system. And poorly implemented cables. There is another problem - usually manufacturers put inductors on both send and receive end in order to meet EMC requirements. These really screw up the impedances - you can see the effect very clearly using Time Domain Reflectometry, see for example here http://www.audiocircle.com/index.php?topic=45330.0 .
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Happy birthday Dan!
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Robb Report: 6 best headphone amps
Craig Sawyers replied to Dusty Chalk's topic in Headphone Amplification
Agreed; huge numbers of bricks and mortar businesses have gone out of business because they have failed to change with the times. High end audio is not immune to this. Good case in point, Analogue Seduction http://www.analogueseduction.net/ who are principally an on-line high-end retailer. You can book a demo (in the guy's front room), but most of his business is via web sales. There are many such examples worldwide, all of which erode traditional bricks and mortar stores. -
The Knuckledragger 3rd Memorial Slow Forum Post
Craig Sawyers replied to Knuckledragger's topic in Off Topic
Pity he didn't do Geordie, from around Newcastle. One of the most difficult accents to do if you don't come from there. Scan though this; close similarities to the Scandinavian languages from the invaders who populated the North East coast of England and Scotland following the invasions in the 800's. There are parts of this in English with a Geordie accent, and bits poetry in true Geordie and Northumrbian. There is also a sub-dialect called Pitmatic, which was spoken by coalminers. Almost died out now because of the decline in coalmining in the North East, but my grandfather, a lifelong coalminer spoke a lot of pitmatic, so my native dielect (when I turn it on, rather than Geordie with and English accent) tends towards pitmatic. -
Happy birthday!
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The Knuckledragger 3rd Memorial Slow Forum Post
Craig Sawyers replied to Knuckledragger's topic in Off Topic
Now that is interesting. It comes out of the the Optical Research Centre (ORC) at Southampton University. I did my research work there in the late 70's in the precursor to the ORC - the Laser Physics group. The ORC was formed when that group (around 10 people) merged with the Fibre Optic group (about the same size). It is now a global leader is just about everything photonic. Led by Dave Payne, who I knew as a research fellow in '77 and is now Professor Sir David Neil Payne CBE FRS FREng - a real academic heavy hitter. -
Very sad. Eco's books were never an easy read, with many layers of meaning (try Foucault's Pendulum) but always worth reading and then re-reading. Eco himself said that he probably wrote for masochists.
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That is another of the greats gone. We studied To Kill a Mockingbird in English studies at school in the UK in 1972. At least she got in a sequel before the end of her very long life.
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The Knuckledragger 3rd Memorial Slow Forum Post
Craig Sawyers replied to Knuckledragger's topic in Off Topic
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The Knuckledragger 3rd Memorial Slow Forum Post
Craig Sawyers replied to Knuckledragger's topic in Off Topic
The old cough mixture photo made me think of a product still available in the UK - Kaolin and Morphine - a cure for diarrhea http://www.chemistdirect.co.uk/kaolin-morphine-mixture/prd-o2d Ingredients: Light kaolin BP 1g, sodium bicarbonate BP 250mg, morphine hydrochloride BP 0.458mg and ethanol. -
Have a great birthday Colin!
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Have a great one, Steve
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The Knuckledragger 3rd Memorial Slow Forum Post
Craig Sawyers replied to Knuckledragger's topic in Off Topic
^^And for the toughest foot race, possibly in the world, 135 miles from Death Valley to Mt Whitney http://www.badwater.com/event/badwater-135/ in midsummer. They wear white coveralls during the day, and run on the white line on the road to prevent their running shoes from melting on the blacktop. -
Robb Report: 6 best headphone amps
Craig Sawyers replied to Dusty Chalk's topic in Headphone Amplification
Wow you have a way with words - I can't stop laughing at that opening sentence; You've made my day -
Saw ACDC in late 1974 at Southampton University Student's Union. Which was the dining hall converted on a Saturday into a rock venue, with the band on a Dexion and floorboard stage we put up in half an hour. Hot, crowded and impossibly loud at a time when bands were seriously loud anyway. Way before anything remotely like a risk assessment, fire hazard issues, and busted eardrums.
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Have a great one, Ed!
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Robb Report: 6 best headphone amps
Craig Sawyers replied to Dusty Chalk's topic in Headphone Amplification
For out and out classic beauty the McIntosh takes a lot of beating -
The one L lama is a priest The two L llama is a beast And I would bet a silk pyjama you're never heard of a three L lllama
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Like the TV chef that I saw demonstrating how to do grilled cheese fast by putting the toaster horizontal, in his own home (Jamie Oliver). That produced smoke too by the bucketload, and made a hell of a mess of his toaster. So you're in good company!
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Jeez. What a way to go. Same thing happened to a guy whose music I used to listen to - Michael Hedges - in 1997. Car went off on road and down 120 feet into a ravine in Mendocino. Took them several days to find him.
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Very best wishes!
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B&O were always innovative, and produced great looking stuff that produced real sound quality. Back in the day (1972/3) I worked on a Saturday in an audio store in Newcastle (UK). The Beogram 4000 had just been introduced with a parallel tracking arm. Apart from zero tracking error, the customer benefit was its total immunity to mistracking as a result of shock. I used to demonstrate that by thumping the deck as hard as I could with my fist while a record was playing. It was one hell of a deck.
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Kind of difficult, since Evans has massive clout withe the BBC - and do or die he is the new face of TG. Will he last in the long term? No idea, but I'd guess he will be around for at least a year.
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If indeed they are dead (after you get them out) you need to find out what killed them. Post the schematic so we can have a look.