Craig Sawyers

It is the winding connected to the output marked "60V power supply" - that adds -60V to -500 to make -560, and the one marked "300V power supply, that adds 300V to the -560V supply to make -260V. And yes - winding wire is supposed to hold off 500V - but I wouldn't like to rely on it. It might be OK at T=0, but after repeated thermal cycles I would not have confidence that it would hold up long term. It is one of the reasons that transformers with an interwinding screen are often unreliable - the devil is in the detail.

I though - nah, that can't be right - the difference must be significant. I remembered Leslie's Cube from schooldays and foggily recalled a much greater effect. But then I found and scanned "An experimental inquiry into the nature and propagation of heat", By Sir John Leslie, 1804 (Readable on Google books) and noticed that the basic experiment only measures radiant effects - not convective ones. So the experiment is entirely relevant for space based thermal radiators (which would have astonished Leslie), but not ones in air. But then I found the comment relating to normal heatsinks: "Under natural convection conditions, the performance of a heatsink with a black surface will be 6% to 8% better than that with a plain or bright surface. However, this differential disappears under forced air conditions." Significantly less than I had intuitively expected - but consistent with the primary cooling effect being convection. The above comment was on Basic Theory , which seems to be a distillation of heatsink info from several sources.

One additional thing that is worth mentioning to a transformer manufacturer is that some of the windings float at high DC. Specifically the heater windings to the EL34's (-500V), and two of the HT transformer windings are referenced to -560V or -500V. So those windings in particular need an insulation barrier - just overlaying one secondary over another probably won't work (it *should* in principle, because winding wire is good for more than that - but not if any insulation is compromised through nicks during winding, or just thinned because of winding pressure).

Sounds amazing Doug! But beware head brewer syndrome. Mrs S is an accountant, but way back when she was an audit junior she was on the stock check team of a local brewery. She was warned not to approach the head brewer until the afternoon until he had done a good session of "sampling" and was not suffering from the after effects of the previous day's sampling.

FWIW my total Mouser bill was

Oh bloody well done! Nice one.

Looks like an interesting outfit - good luck!

Have they seen the 80's Thomas the Tank Engine TV series with Ringo Starr doing the voice over? Allegedly Starr was using doing the series as part of rehab coming off the booze. Anyway, the early series with Starr were iconic and excellent - my kids were of that pre-school and early school age when it was first aired, and I had great fun watching it with them.

Well, I sure sweated doing the precise same thing in my driveway. Got to a sweltering - well for the UK sweltering - 30C (86F). Hasn't rained for what seems months. English Lake District, which was at the receiving end of near biblical flooding in October 09, is now in an official drought with hosepipe use banned.

New series of top gear. Usual mixture of madness, capped off by May driving up an Icelandic volcano (the same one that blew its head and disrupted air travel). Tyres eventually burst into flames at which point he retreated.

Because I have little or no interest in the sport, I valeted our older car as a graduation present for our daughter. But I could tell the inevitible was happening by a stereo groan of despair coming though open windows along our road as each goal went in against England. Now we'll have to get through days of navel gazing by the pundits. There will be no repite....

The series got better as it went along, with the brilliant one liner to finish off "NOW what do we do?". Can't wait until the next series.

Jeez - if that birthday party has been going on for 3 years, it is no wonder the beer has expired

This has just got to be the wrong list for discussing running shoes - but the theory behind these is that since 50% of the bones in the human body are in the feet, they are there for a purpose. The whole foot is a very advanced shock absorbing system, intended to be in touch with what it is running on. The arch is part of that - ideally with the foot striking on the outer edge of the foot, rolling inwards towards the arch (which flexes downwards as it takes the load), the heel touches the ground very lightly, and the the calf pushes you off again. And yes - track racing flats (apart from the spikes) are not dissimilar in the correct lack of support of five-fingers.

Another UK source of UNC fixings, including black, in various headstyles and 1/8" length increments http://www.modelfixings.com/

Scratch the 10mm comment - the board height is fixed by the heatsink bracket position.

I wondered what the second coupling was - that is a really neat design, and keeps visible shaft grub screws completely out of the equation! With the fancy Alps, you have to go *up* from 1/4" to 8mm, whereas with the DACT you need to go "down* to 6mm.

Maximum EPCOS height above the board is 47mm. How about slightly shorter spacers? Specced ones are half inch, so would 10mm work better?

You into Salad Fingers too?

Mushroom mushroom

Big problem here is badgers. They are either a protected species (like if you want to do a building extension) or subject to government organised culls (because they carry bovine tuberculosis). Factoid - the M25 London orbital has tunnels for badgers and othe wildlife to use to get from one side to the other. Not to protect the wildlife, but to prevent accidents as motorists swerve to avoid them.

Did they mask casework areas that are in electrical contact?

When I was a student living in a typical student flat, I was infested by mice. Being an electronics student, I took some strip board and wired each alternate strip to live and neutral, put a piece of cheese in the middle and switched on, the aim being to electrically fry the sods. The only thing that happened was my nerve broke first, worried about getting up in the morning and standing on it. Mice took absolutely no interest, until I turned the power off - then the little buggers ate the cheese.

Based on the assumption that KG's knob is 1/4" (waits for the inevitible comments...), since the panel bearing specced is for 1/4" rod, I need to transition from 1/4" rod to 6mm shaft for the DACT. I've therefore bought a 6mm shaft coupler (Rapid Electronics), and will ream half the length out to 1/4". I could of course turn the 1/4" rod down to 6mm at one end, if I had a lathe (but I don't), so adapting the hole size in a coupler is much easier.

Oh - sure they are not a new product, but they are new to me. I'm a forefoot striker anyway, and in 40,000 miles of running have never had any wear marks on the heel of any running shoe. So apart from aching calves due to the different foot angle I think I'll adapt quite well. The wierd thing is that I've been used to a sort of slap, slap sound in conventional running shoes, but with the five-fingers with zero support anywhere I am almost totally silent - just a very quiet padding sound. The statistics are interesting. Since Nike introduced the modern running shoe as an advance in the sort of flat and flexible shoes that preceeded them, there has actually been an increase in running injuries. Stretching before and after a run? Also no impact on injury rate. Speed? Famous bear foot runners are pretty rare, but Abebe Bikela won the 1960 olympics marathon in bare feet. Bruce Tolloh was a world class middle distance track runner in the 60's/early 70's (he used to surgical tape each toe though), and Zola Budd also ran barefoot in the 80's. But track spikes are light and flexible anyway, with no heel and hardly any support - so are not dissimilar to barefoot running with additional traction.