TimR

[quote name='discreet' timestamp='1392729059' post='2371993'] It's complex enough in theory, thanks... [size=4] [/size] [/quote] Ok. Well the noise appears on both lines but is equal and opposite on each so cancells out. You probably don't need to know in much more detail how.

[quote name='discreet' timestamp='1392688335' post='2371702'] Woosh! Right over me 'ead. [/quote] Noise would add to both signals. If the signals were +1 and -1 and the noise was +0.1. At the mixer you would see +1.1 and -0.9. Invert -0.9 gives +0.9; 1.1 + 0.9 = 2. Without noise; 1 + 1 = 2. Obviously it's a lot more complex in real life because we're taking about frequencies and phases etc.

[quote name='MoonBassAlpha' timestamp='1392676241' post='2371595'] It makes you think about the ritualistic element of "healers" of various ilks. Is it all about releasing the inner healing abilities of the body? The more ritual, the more buy-in. Probably includes church and prayer too... [/quote] I think there's a lot more to this than meets the eye, as it were. Even your subconscious can't be fooled by your concious? Subconsciously, you know you've taken medicine. I think this is similar to athletes at the elite end who don't understand that they can fail, it doesn't even enter their thoughts that they won't win. While some of us are doubting whether we will complete 26.2 miles, there are others who are wondering how they will get even faster than they did last time and beat their rivals by a bigger margin. And those that doubt whether they can run 26.2 generally end up walking at some point. I wonder about the woman who was taking a placebo and then tried to buy one at the health food shop. Did she actually understand what a placebo is? Optimists generally do better in life than pessimists. Self fulfilling prophesy? Your mental in physical wellbeing are completely interlinked.

[quote name='Dad3353' timestamp='1391111810' post='2353490'] We often refer to electricity as being a 'positive' and 'negative'. We have two wires. Often the screening (or 'earth'...) is used as one of these wires. Ordinary guitar jack cables are like this; the signal goes through the centre wire, and flows back via the screening (also called 'ground'...). All well and good, and inexpensive, but when we need to use longer cable runs, such a s a 'snake' multipair from stage to console at back of hall, these inexpensive cables pick up interferences (hum, transient spikes...). To reduce this pollution, the signals goes through two distinct wires, which have a common screening. Neither of the signal wires go to earth; they are seperate. Where two pins sufficed for 'unbalanced' jacks, three are required for 'balanced' signals. Microphone XLR cables are an example. The material using balanced signals will typically be designed for receiving low-level signals, independant from the earth screening. The pins, impedance etc are designed to cater for this. That's the role of the DI. Any clearer..? [/quote] Not quite. The signal flows equally down the + and the - wires and back through the ground wire. But in the - wire it is an inverted or a mirrored version of the signal in the + wire. At the mixer the signal in the - wire is inverted so now becomes a positive signal. This is 'added' to the positive signal in the + wire. So now you have twice the signal. BUT any interference on the cable will affect both signals in the same sense. So, at the mixer, the positive interference on the - wire becomes negative interference and when added to the equal but positive interference on the + wire, the noise is cancelled.

[quote name='jgmh315' timestamp='1392583493' post='2370396'] Parcelforce don't cover musical instruments. [/quote] Well spotted. Their enhanced compensation won't cover only their included compensation. Which isn't £3k.

Royal Mail parcelforce cover to £2500. You could risk the £500?

[quote name='flyfisher' timestamp='1392570322' post='2370154'] One aspect of placebo research is the ethical implications. So, for example, it would be unlikely to be deemed ethical to conduct a clinical trial of a cancer drug versus a placebo because it would require the withdrawal of treatment from the placebo group. ... [/quote] I don't know but would expect that you wouldn't use a placebo in that instance. You'd keep one set on the tried and tested drugs and the other set on the new drug.

When comparing an amplifier or bass you need to have someone else play the two while you look away and are not told which one is which. Otherwise you will always use as much information as is available to you. There's another link somewhere that demonstrates someone ab-ing two amps, one with no insides but made up to look like a tube amp with glowing tubes etc. The ab switch does nothing. The tube afficianodos all say it sounds better when the switch is 'switched' to the tube amp.

[quote name='White Cloud' timestamp='1392569789' post='2370145'] Thanks for sharing Tim. It is a very interesting video...and I don't doubt it's validity & it proves the point you are making well, however very often [i]seeing is not believing[/i]. For example whilst undertaking the test...all you have to do is close your eyes and[i] really listen [/i]to remove any ambiguity. It's simply a case of trusting all of your senses... [/quote] That's exactly my point. You HAVE to close your eyes otherwise your brain overrides the other information with the information provided by your eyes.

Take the McGurk effect test. Posted on another thread, I'm not taking the credit for it. http://youtu.be/G-lN8vWm3m0

I've watched some of his films. Once... A tormented man.

Yes. All very frustrating. Then you'll set up in an acoustically awful venue and start all over again I've found the first thing to check when I'm not happy with my sound is my finger nails, then the battery in my active bass. After that it's where I'm standing in relation to my cab and where the cab is in the room. Maybe I add a bit of high mid on the amp. I'm using Bass Centre Stadium strings, I don't even know how long they've been on, or if they sell them anymore. Maybe worst case scenario I'll change them. Other than that, shrug my shoulders and just play the notes...

Yes. 7 years old?! It's pretty much accepted that humans rely on our sight more than any other sense. Our brain will override anything we hear, smell, feel, taste in favour of what we see. Placebo effect is mainly because most of our illnesses are made worse by our negative emotions. If you are in pain for a long time, you will become depressed and end up needing far more painkillers to dull the pain than if you take a small amount early on. Many of us can cure headaches and other minor aches and pains just by disassociation. Placebo works in a similar way.

[quote name='The Admiral' timestamp='1392512682' post='2369646'] Mrs A and I were invited to see a band at a local venue tonight - a fundraiser for a cancer charity, free entry, money in the bucket for the charity. ... Tonight was their first big gig (250 plus punters), following the departure of the second guitarist and bass player, so the new guys they had recruited were under a bit of pressure. ... [/quote] Reading these two parts in more detail. The band were doing a free relaxed gig to punters who weren't paying, possibly with the aim of giving the new guys an airing. But mainly with the aim of raising some money for charity in a fun relaxed atmosphere with friends and fans.

We're going to take a 5 minute break for 10 minutes, see you in 15... Even pros can leave you hanging on; Axl Rose? We went to see Richard Bona at the Camden Jazz Cafe. Doors open 7 but we know the acts never start until 9 so we went for something to eat first. But were in the venue at 8:30, Inthink he came on very close to 10:00, at 11:00 lots people were leaving so that they could get the last train home. I suppose the band may well have only been asked to play two sets with an hour break. I've done charity events that have been really badly organised by well meaning people who haven't got a clue and won't listen to reason. "We've only got £300 for the band, what can do? 2x45mins? OK my mate has an iPod we'll put music on over the PA for people to dance to, in the break."

[quote name='Muzz' timestamp='1392114958' post='2364746'] ... interact ... [/quote] Good word that. Doesn't necessarily mean talk. It's a two way street. If the audience don't want to play, there's always your band mates. And it doesn't necessarily mean talk.

[quote name='flyfisher' timestamp='1392481110' post='2369261'] What, like these you mean? [/quote] Yes. Exactly like that. You acknowledge that there are circumstances where you can't cover everything. Then when Stu and I suggest that there are circumstances beyond our control, we are somehow wrong.

I am sorry but when you make statements like those below, it leads me down a certain avenue of thinking. [quote name='flyfisher' timestamp='1392310779' post='2367182'] ... RCDs are the thing to help prevent electrical shock, not fuses. And even RCDs can't offer total protection. [/quote] [quote name='flyfisher' timestamp='1392421764' post='2368729'] ... 5. Both you and TimR think sh1t happens ... [/quote]

It's personalised because I know you are/were a company director and I can't believe you are so ignorant of your responsibilities under the health and safety at work regulations. This leads me to feel once again you are playing devil's advocate and presenting straw man proposals deliberately to prolong discussion. I may be wrong and you may be completely ignorant of your responsibilities, which is an entirely different debate.

[quote name='flyfisher' timestamp='1392465808' post='2369033'] Now that's the most constructive post so far in terms of better understanding this whole thing. Interesting. [/quote] I mentioned that earlier and you even quoted it. It will form part of my experiment.

[quote name='tauzero' timestamp='1392424601' post='2368759'] At the risk of perpetuating this yet further, the other thing to consider is contact area. While a fuse has a big flat contact area to go into the big flat [1] fuseholder, the threaded bit of a bolt provides a series of teeny-tiny contact lines. That's going to be the major factor in considering the current-carrying area as a fuse has a considerably larger contact area than conductive cross-sectional area, while for a threaded bolt the reverse is true. [1] Well, curved, but an even surface [/quote] And does the bolt fit the holder or is it rattling around, expanding and contracting with the heat.

I'm going to wire up a bolt next week and see what happens.

So a 6mm bolt has a cross sectional area of 28mm2 which is close to 10x 2.5mm2. But that's of passing coincidental interest. Lol.

[quote name='flyfisher' timestamp='1392419261' post='2368698'] @TimR - Industrial datacomms equipment. Why are my questions strange? And even if you think they are, why not try answering them? The volts drop across the bolt for example? I'm asking it because your post estimated 6kW "through the bolt and fire system combined", which is fine, but I'm sure you understand that the amount of that power that is actually dissipated [i]within[/u] that bolt and therefore acting to heat it up, will be largely dependent on the voltage across that bolt. Which is why I asked the question. Is that really so strange? [/quote] No. It's the constant questions when you get an answer you question that as well. It gets worse because the fuse at the DB would be a 30amp and probably capable of 40-50 amps for a couple of minutes. The bolt (if carbon steel) would have to have 10times the cross sectional area of the copper to have the same resistance. Then we also have to look at contact area and resistance of the bolt with the holder. As big Stu implies unless you do a forensic examination of the whole thing it's all educated guesses. Fires do happen due to faulty electrical equipment that's protected correctly and tested and checked regularly but they happen more often to equipment that isn't. Check your gear regularly and don't cut corners because it's not expensive. It makes sense.

[quote name='flyfisher' timestamp='1392418001' post='2368682'] Doesn't that sound like a case for suggesting that the fittings involved are not adequately protected by the rated fuse? I know that a 13A fuse will not blow as soon as 14A flows through it, but so do the people that define all the wiring regs, so you'd think they'd take account of that sort of thing wouldn't they? 'Hopefully' sounds a bit vague for a H&S procedure to me! [/quote] What can you take account of? You can only cover so many scenarios. Sometimes as big Stu says 'sh*t happens'. That's why we have regular checks, sprinkler systems, fire alarms, fire brigade and so on. By 'hopefully' I mean that the evidence of overheating is present when the PAT is done and not after. You can't catch everything, you can just try to catch them. What did you say your business did? You're asking some very strange questions for a director of an electrical design company.