Monday 30 March 2015

Clivia in bloom

The Clivia that my Mum gave me is making a magnificent display, it's currently in the hallway to show it off.

Sunday 29 March 2015

On cables and sound

I posted just a little while back about my project to build some new amplifiers for my stereo.   I had a little problem with the power supply for one of the amps - it gave off a spark when switched on.  I sent it back to Hypex, who told me that they couldn't reproduce the problem, but they sent me a new one anyway.  So I installed it, fired up the amps, and they worked fine.  So now they form part of my stereo.  Here's a picture - the new amps are the two side-by-side silver boxes halfway up.

One of the things that I noticed is that they new amps have a bit more top end that I'm used to - they're a bit trebly.   I don't know if that's because the amps have to be run in - that's a common enough phenomenon.   But as it happens I have a set of very fine audio interconnect cables that I have used on systems in the past, that tame a slightly wild top end, and I swapped them into the system. Perfect.

Now, I know that audio signals fall into the lower end of the frequency spectrum that cables might have to deal with, and that measurable effects on cable performance only start to come in at radio frequencies.  I have debated with friends of mine about whether or not  choice of cables can impact the sound of a stereo.  The only proof is by demonstration, and I have shown puzzled scientific friends that two different types of cable, both of which should be perfectly adequate for audio, give very different results.  And they then sit and debate what might be happening.  As far as I'm aware, right now, no-one really knows.

As a listener to music, I really don't care what's happening, as long as I like the result.  As a scientist, I'd like to know.  And the trouble with no-one knowing, is that there tend to be forwarded all sorts of nonsensical explanations, most of which relate sound quality to the price of the cable.

Never mind.  Enjoy the music.

Friday 20 March 2015

On energy

Here in the Mayenne there is a problem with water pollution.  There is enough fertiliser run-off going into the rivers and streams that the Powers That Be are worried about it.  I don't strictly know if the water fails to meet EU standards, but, evidently, Something Must be Done.

There used to be many water mills along the rivers that thread through the Mayenne, and each one had its dam and sluice gate for water management.  The mills have fallen into disuse but the dams and sluice gates remain, and these slow down the flow of water enough, apparently, to cause the pollutant concentrations to reach unacceptable levels.    The solution being proposed (and, by degrees, inplemented) is to destroy the old dams to speed up the water flow in the rivers: the rivers will flow more swiftly, the water levels will drop, there will be less time for the pollutants to accumulate and they will be carried away faster.   I believe that part of the argument for this approach is that sunlight on the pollutants causes chemical reactions that increase toxicity, and the less time the water is exposed to sunlight, the less the danger.

Well, fine.

The problem that I have with this approach is that, in energy usage terms, it's short-sighted.  Water mills are a low-tech and reliable source of mechanical energy that can be turned into useful electricity with a combination of three (relatively) low-tech and easily-available electrical components: an alternator, a battery and an inverter.  Given the way that electricity is becoming more and more expensive, and in greater and greater demand, I'd be looking for ways to exploit reliable water power rather than to destroy ways of making it.

The moulin du Gô just down the road, I am told, would generate about 7 kilowatts.  If it were my mill, that's what I'd be doing with it.  I reckon that with good energy management, you could run a reasonable-sized flat in a building like that with no need for a connection to mains electricity at all.

Heating the place in Winter would be the biggest concern.  7 kilowatts (peak) is not enough to heat and cook with, using traditional methods, even if the building's thermal insulation were of the best.  You could use a heat pump that would give you about a three-times return on the electrical energy you put in, but the problem with heat pumps is that they are less efficient in cold weather, and the last thing you need is a heating system that, as an innate characteristic, doesn't work well when it gets really cold.

So I'd go for burning wood as a source of heat.  It's renewable and carbon neutral (over the life of the tree) and also extremely low tech.  If all else fails, you can probaly still light a fire, and if necessary cook on it.   That leaves the electricity to do the lighting and, usually, the cooking.  With 7 kilowatts you would have to be careful about having the oven, microwave, kettle and hob running at the same time (of these the hob would consume the most), but with a bit of forethought you could prepare any given meal.  And perhaps with some electricity stored in batteries, you could exceed this consumption at peak times.

And as for burning wood, the gîte here, and the house (and the pool) are all warmed tht way.  You can get raw wood in the form of a felled tree, for 16 euros the cubic metre - you have to cut it up, transport it and dry it out yourself.  5 cubic metres will warm our house for the Winter (we needed less than that this year since it has been mild).  My pal Leo has found a local source of oak, and yesterday we were chopping up a tree into manageable bits.  A nice way to spend a sunny morning, and (give or take the petrol-powered chain saws) low tech and carbon neutral.

I've been keeping an eye open for water mills for sale.  Ideally it would have to have a functional wheel, but with buildings in need of a full renovation so that you could insulate them effectively without trashing too much functional finishing.  I'd have to sell this place first though, and that's a possible long-term, rather than an immediate, plan.  Here's an example mill for sale.  It has possibilities, but I think they're asking a bit much.

Friday 13 March 2015

The garden starts to do its thing

I couldn't believe it yesterday, seeing a couple digging up Primroses from the bank beside the road.

Monday 9 March 2015

New adventures in crockery

So there we are in this factory china shop, buying lasagne trays.  Not a particularly interesting passtime.  But I was surprised to see a new invention: crockery pots that you can use on an induction hob.  Apparently they are especially resistant to thermal shock, and you can use them on any kind of heating appliance.  We bought one.

The company has a patent on the material.   (French for patent: un brevet, that is also the same word for diploma or certificate).

Sunday 8 March 2015

Breaking good

When equiping a gîte with crockery, glasses and cutlery, one must bear in mind the ease of replacement in case of breakages or loss.  Glasses and plates inevitably get broken from time to time, and cutlery can slowly disappear as it gets lost or misplaced.   They need to be replaced with items that match or after a while you end up with a random hotch-potch of table settings that don't convey the right quality image.

We forgot this rule when we were on holiday in Brittany, when we stumbled across a nice little shop selling a vast range of nothing but white porcelain.  We bought a set of four oven-proof lasagne trays (one for each available oven shelf), to replace other supercheap ones that weren't coping very well with being put in the oven.  And inevitably, one of the four we bought got broken.  They're the type of tray you can use directly from the oven, to serve the meal, so we have to have four the same.

Getting a replacement wasn't easy.  The shop is about 4 hours' drive away, and neither the shop nor the factory will ship by post because they are fed up with things getting broken.  So a personal visit is necessary.  And it so happens that if you are prepared to take a relaxed or creative approach to the concept of something being "on the way" to somewhere else, a visit to the factory is not out of the question if you are travelling between our place and Paris.

And since we were off to a concert in Paris, and also wanting a short break, we ambled down and stayed overnight at a B&B in this lovely Chateau de la Brosse, not too far from the factory.  It's run by a Dutch couple, the latest in a line of recent owners who have done various renovations.  Previous couples in this rôle have divorced, so they are avoiding the curse by not getting married.   The renovations are excellent; I don't think I have seen a chateau in such excellent repair.  The outside walls in particular are bright, clean, and recently refurbished by a master of the craft over a period of some eight months.   The rooms are spacious and comfortable, and children are not allowed, so the place is peaceful and the decoration has a better chance of maintaining its condition.

As it turns out the couple are also car racing enthusiasts who have friends in Holland who, from time to time, are looking for good group accommodation for about 25 people, not far from Le Mans.  Could be right up our street.

Wednesday 4 March 2015

Sunday 1 March 2015

Light and sound levels

As my avid reader will have surmised, music is my preferred art form.   Not that others have no place, but it's music that moves me the most often, and the most effectively.  And it's the art form to which I contribute, in my modest and amateur way, via my flute.

And so it's this, I imagine that drives my interest in hi-fi.  I like to listen to music at home, and when I do, I like it to sound as realistic as possible.  I have listened to enough hifi equipment over the years (I used to trade in it in my spare time), to know that they all sound different, regardless of what the measurements will say, and I have a good idea of what is good and what isn't.

I have been happy with my current stereo for a while.  The key component is the speakers, they come from here, and to my ears they are hard to beat.  They aren't cheap, though.  The amplifiers I have been using are these Bantams from Temple Audio.  They are very cheap compared to the speakers, and you'd imagine that they could sound rough, but they don't.  They rank amongst the very best I have ever heard at any price.  They are based on recently-developed digital amp technology.

There is only one problem with them, which is that they don't go very loud.  And here we come across a problem of English usage: I don't mean that they only play at very modest sound levels, I mean that they don't go very loud, even with the Bastanis speakers that are quite sensitive.   And there is some music that just needs to be played loudly.

When you turn up solid state amps too loud, they start to clip the waveform, which presents as a harshness to the sound, that makes them sound like they're playing loudly, even if they're not.   The more you overdrive them the harsher they sound as more and more of the waveform gets clipped.

It's quite noticeable at concerts that the music is playing much louder than I listen to at home, without any form of harshness.   What's more, my ears are not what they used to be.  Distant and and mid-field crickets no longer form part of my soundscape, and bats that I used to listen to as a lad now flutter silently overhead.  And a tinnitus left me by an unfriendly ear infection needs to be drowned out as well.

So I have resolved to replace my amps with more powerful ones.  I have chosen these, the NCORE400 amp modules from Hypex electronics, that use the same digital concepts as the Temple Audio Bantams, and have been well-received by the DIY community.  They come in kit form - amp and power supply, you have to put them together, and you can get nice housings for them on the commercial market.  I chose these ones from Ghent Electronics in China.  Putting them together is a bit like plumbing - just a bit of soldering involved, nothing too tricky.

(I suspect that these amps are the ones used in the B&W Zeppelin, since the amps are round - a strange shape for an amp unless it's going into the Zeppelin, and Hypex do supply the amps for it.  And Hypex are explicit that they don't want OEM enquiries for the amps, so perhaps B&W have an OEM exclusive.)

Here's the two amps and power supplies, all nicely wrapped in anti-static bags, laid out ready to mount in the case, and a pic of the modules installed.

Here's what the back panel looks like, and the finished article.

Now when I first plugged it in and turned it on, I did so with the top off the box.  Experience has taught me that if anything is going to go wrong, smoke or other evidence is more quickly and easily seen with the electronics exposed.  I also wired in an old cheap speaker since something that can dump 400 watts of audio into a loudspeaker when it's working properly, could do a lot of harm if it's not working properly.

Click went the switch and phut! went the spark.  Odd, but after that the amp seemed to operate OK, and subsequent switchings on and off gave rise to no spark.  It all seems to work fine.  But then then next day, turning it on from cold produced another spark.  So I contacted Hypex tech support: "is it supposed to do that?"  "Noooooo!"

So this aspect of the project is on hold while we resolve what's going wrong.  Looks like a dodgy power supply to me.  Meanwhile I'll put the other amp together and see if the problem reproduces.
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