u wot mate?

From the article: "tumours cannot form in nerve cells". This, of course, is BS that was discredited a couple of years ago: http://m.medicalxpress.com/new... Perhaps we should have a Slashdot discussion on lazy scientists failing to keep up with developments in their own field. If you write without bothering to read, you end up with... well, something like Slashdot...

http://news.nationalpost.com/2...

The New Testament supersedes the Old, so the post is invalid. This applies to most branches of Christianity. The parent poster is either trolling or ignorant of that which he is criticizing (my guess: copy-pasting random collection from teh intrawebs). The various interpretations are all aligned with this. Catholics, for example, interpret the Law of Moses (the Old Law) as a preparation for the Gospel, and as such no longer binding; the New Law (the Law of Gospel) is a perfection of it, delivered through faith in JC. Disclaimer: I'm an agnostic atheist (as in, no god with 85% confidence).

They exceed it in a limited frequency range, as I pointed out. I'm pretty sure you measured at say 1 kHz and "done deal", instead of sampling the full 20-20k range and noting how especially at the higher end SNR degrades. You also completely ignored my point that 90 dB is not the right target, as the ear does 120.

Let's be more specific about the notion of "sound the same". I don't know what it means to you, but I take it literally: that it is impossible to distinguish for any human in a set of blind tests, let's say ITU-standard ABC/hidden reference form, between these amplifiers or whatever other DUT we have (let us suppose that we can agree on a reasonable sample size of trained listeners, and a reasonably long time limit — I would push for several hours, split over a few experiments.) The 120 dB provides an upper bound to the noise and distortion, a guarantee that any reproduction equipment that meets that distortion spec will cause no possibly detectable change in the sound. I don't suggest that my bound is tight. However, you have failed to present an argument for a significantly tighter bound. You might argue against my basing of my argument on listening in ideal conditions, but such can be approached to varying degree in practice, and so I'm discussing the limiting cases, not the typical ones.

While a CD has a 90 dB range, typical players don't achieve that SNR, except maybe within a narrow subrange of the audio band, and the THD is several dB worse yet. You forget that the digital side has all the bits, but you need to convert it to analog. The DAC chip and the subsequent stages are the issue. At the digital/analog interface, signal jitter remains a problem, especially since phase noise performance of the cheap clocks used in even mid-upper range players is rather poor. There are many other issues, including poorly designed upsampling filtering before the DAC and so on. Moreover, you're forgetting that there's increasing amount of 24 bit, 96 kHz/192 kHz content, so the goal there is 120 dB, not 90. This far the only commercially available DAC chips that handle jitter issues, filtering, and the actual analog conversion sufficiently well for that target are the ESS Sabre models (ES9008 etc); the white papers are interesting. There are also some hobbyist stuff built with Sharc DSPs that can be found at the diyaudio forum.

I would hazard a guess that his headphone tube amp is output-transformerless. The truth is that what most people think of tube sound is really output transformer sound (the exception being the soft clipping, of course).

The human ear has a 120 dB dynamic range. While we're not all listening in anechoic chambers, studies show narrowband signals are detectable as much as 20 dB below a broadband noise floor. Now, very few amps achieve distortion and SNR that can cover this range (indeed, I'm not aware of any commercial ones — only a DAC that exceeds that range, and a few circuits prototyped by a few crazed members at the diyaudio forum). This means that the suggestion that solid state and tube amps that are properly designed sound the same is incorrect. There is no "linear range"; only an approximately linear one, which is still not completely linear with respect to psychoacoustics. I think what you meant to say is that well designed solid state and tube amps sound practically the same to most people in typical listening conditions. Please see my comment here as well: http://entertainment.slashdot....

>"And don't even get me started on the tube mythologies."

What do you mean? In the end, a tube is just a gain device, like a transistor. Given a distortion spec, one can just as much build a tube amp to match it as a solid state one. There are both SS and tube audio amps that achieve distortion levels in the part-per-million level. Multiple gain stages are required in either case to get very low distortion; the real fault in most consumer tube amps is not the use of tubes, but the use of circuits that are too simple — that's the audiophile fetishist fault. Indeed, a single (constant current source loaded) vacuum triode is more linear a voltage gain device than any single transistor. If you use as many tubes as transistors, you can easily match the low distortion levels of the SS design. Tubes have specific benefits including removing thermal memory distortion (modulation of gain device parameters by the temperature changes caused by varying power dissipation). See for example this AES paper:http://www.aes.org/e-lib/brows... With transistor designs, to deal with the issue you need to add more devices to even out the power dissipation at least in the differential pair input and the VAS, and in the case of chip power amps, add compensation for the effect of the output stage thermal dissipation affecting the previous stages. Then there's the issue that transistor gain curve is exponential whereas the tube's is power-of-two, which makes the distortion profiles of a tube and an SS amp that achieve the same THD quite different, with more of the THD in the tube case caused by lower order and even harmonics — the very ones that the human auditory system masks anyway (psychoacoustics what ultimately matters, and there is interesting research and AES papers on more relevant metrics than THD/IM). Tube's problem is simply one of practicality in regards to their size and the need for filament power. Other issues can all be dealt with. For example, in terms of typical speakers, the low impedance has been traditionally solved with transformers, which introduces phase nonlinearities and some hysteresis effects, so they add distortion. But this is unnecessary. One elegant solution is the replacement of the output transformer with a switching impedance converter that operates far above the audio band; see D. Berning's patent (I think it expires soon). While the converter is an active SS state, it has no gain and no distortion in the audio band. Another solution is to directly couple tube output to electrostatic speakers, which have very high impedance. A third solution is to use hybrid circuits with both SS and tube stages. It's possible to get the best of both worlds there. Here's a great hybrid circuit that achieves a few ppm THD for 1500 kV p-p output for electrostatic headphones:http://headwize.com/?page_id=7... Note especially the hybrid third-fourth gain stage. One reason the amp gets such low distortion with only moderate NFB is that the third stage transistor's nonlinearity, in the operating range, is roughly inverse to the final tube stage's nonlinearity.

It will be for the worse. While the level of resistance of a system of inequality (hierarchical civilization) to revolutions that remake the social order has not been increasing monotonically throughout history, on average it has been increasing. In recent times, sufficient corrective feedback mechanisms have been integrated into human society that, in my opinion, successful revolution is impossible. Save for a global catastrophe (whether manmade or natural) that decimates the population, the current trends will continue. The endgame I would bet on is that advanced robotics will make poor people obsolete; what happens to them at that point is going to be something akin to what Marshall Brain wrote about in his story "Manna", minus the happy ending. So, you can't beat them, and chances are against you joining them. Upward mobility is mostly a game of luck no matter how skilled, dedicated, and intelligent you are. However, playing this lottery is the only hope, small as it is, that you, as a representative of the non-elite, have to create a decent life for yourself and your offspring.

The surface of the collapsing star takes an infinite time to cross the event horizon form the point of view of an outside observer? No star which has collapsed has yet turned into a black hole, and no one will at a finite age of the outside universe. The only way to prove the existence of a black hole is to fall through an event horizon. Of course, then you only prove it for yourself, and cannot tell anyone else.

Is that clip supposed to be funny, Chris? My gosh, whatever happened to British humor? From the heights of Monty Python and Benny Hill, it's been a precipitous fall to this.

Cursive exists because it's faster. This is why the letters are joined; it's not for looks. If it was about the latter, they would still be teaching Spencerian script in North America and similar systems elsewhere. There are other benefits: http://www.nytimes.com/roomfor...