Craig Sawyers

I shudder to think how they datamined the order number. Either Mouser has a massive leak, or what else?

Depends on the size of your ears

Here in tiny island Britain, this was a scary time. Very locally we had an airforce base called Greenham Common, where nuclear tipped cruise missiles were stored, as part of an agreement between Thatcher and Reagan. In the heat of the cold war (ie early 80s), launcher trucks with these on board were driven around the lanes locally to provide a moving target. All part of the Thatcher-Reagan era. There was a permanent Peace Camp there, staffed uniquely by women for decades. In US terms this is the equivalent of driving nuclear weapons around a thirty mile radius of, say Boston. If Boston was a few hundred miles from the USSR. Back in the real world, Greenham Common is a business incubator. But close (in UK terms, within 30 miles) to Greenham Common, near Reading, is AWRE - the Atomic Weapons Research Establishment. Plus ca change etc.

I'd forgotten that there was a kit. I've bought things from these guys before - and they are very cheap and exceptionally high quality. Multilayer 4 oz copper is kind of standard. And they do the lowest noise variant of the Jung super-regulators.

A DC offset on the mains can cause hum. Usually caused by a local industry pulling power out on half cycles, so either the top or the bottom of the mains waveform is flattened (but not both, or not equally). What happens is that the effective DC offset biasses the core of the transformer, and you hear harmonic distortion through magnetostriction in the core. There is a good article, and method to remove it here http://sound.westhost.com/articles/xfmr-dc.htm Basically two big electrolytics in opposed series, or back to back parallel, with diode clamps across them. In series with the live power. Worth a bash since some have silent transformers and others don't, which could well come down to local variation of mains quality.

Well the hum thing is pretty disappointing. Every transformer that Paul has wound for me is as silent as the grave - including the T2 ones. When he was head designer for Avel Lindberg in the 1980's through to mid 1990s he designed transformers for Krell and umpteen other high end and pro audio companies. If you are getting hum, seriously please take it up with Paul - he will be more than keen to sort it out. I'll mail him and let him know that there is a problem in advance.

Woah - apologies for the lateness - I was away celebrating my own birthday Nate - hope you had a great one!

A good mate called Bob Wightman, that I've done a lot of running with on the fells, did a lot of major league climbing when younger. Have a look at the picture galleries here http://bobwightman.co.uk/climb/climbing_gallery.php I was one of his pacers on his successful Bob Graham Round (67 miles and 29,000 feet of ascent in less than 24 hours) in 2005.

Ironically Frank Kelley died on the same day as Dermot Morgan (the guy who played Father Ted) 18 years ago. At least Kelley got to 77; Morgan died suddenly at age 45, which was what finished off the immensely enjoyable sitcom. Feck! Arse! Drink! Women!

Yup. But do a google image search for extreme ironing - there is a whole (very strange) subculture out there.

Extreme ironing

Thanks everyone! We've been away walking in Wales (and boozing etc) to celebrate the next age milestone - 60. Pass the walking frame..... We got all four seasons in four days. Driving sleet at 2C, glorious sunshine at 13C, snowstorm at freezing. Every sort of clothing needed - full weatherproofs, walking poles and gaiters to shirt sleeves. Great fun.

It is always nice when a problem is found, particularly if it is straightforward. When I built mine ages ago the damned thing blew up big time - sparks even - as a result of fake sand Took out most of the heatsink mounted transistors in one fell swoop.

Have a great one Naaman!

Here's a different and no less scary set of views

^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 .

Happy birthday Dan!

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.

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!

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.

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.