Re: laptop audio

I was referring to the THICKNESS of the copper layer, not the WIDTH of the traces (I was also referring to the thickness of the board material itself (the fiberglass)). While there is some slight issue with regard to frequency, this is primarily a quality issue, and when the layers get very thin, they are more prone to being cracked if the circuit board is flexed.

Even so, the dimensions have very little to do with the frequency of the signals. Not nothing, but not that much.

[A good example is Gigabyte modern Core i5 and i7 motherboards, which make a specific point of their "3 oz copper" ((weight of copper per unit of area) which is quite thick as circuit boards go) and thickness .... and these are clearly higher frequency boards than laptops.]


M.I.5¾ wrote:
"Barry Watzman" <WatzmanNOSPAM@xxxxxxxxxx> wrote in message news:hcnkd7$kcu$1@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Re: "I am not convinced that there is a decline in built quality either"

If you have been taking apart a variety of models made over a 15-year period, your doubts about that would disappear very quickly. They don't build them like they used to. It's only partly cost related, the pressure to make things smaller and lighter (and, especially, thinner) also contributes. The circuitry, the ICs and other components, are not the problem. It's the overall mechanical assembly, everything from the thickness of the motherboard and the thickness of the foil traces to the all-plastic (thin, cheap plastic) cases. The build quality is not what it used to be. Again, the problem is not the components (which includes the hard drives), it's how those components are assembled.


The dimensions that you refer to for the motherboard are a function of the frequency of the signals that the traces are required to convey. As the various clock speeds rise, the traces have to become narrower to minimise the series inductance. At the same time the traces have to be closer to the ground plane to allow the signals to propagate with the minimum of reflections. This points to thinner motherboards with narrower traces. I agree with you about the plastic mouldings though. Breakage is all too common, but worse is the tendency for the lid to crack around the hinges precisely because there is unsufficient meat to withstand the flexing as the lid is opened and closed.


BillW50 wrote:
In news:hclr0h$thk$1@xxxxxxxxxxxxxxxxxxxxxxxxxx,
Barry Watzman typed on Mon, 02 Nov 2009 00:34:06 -0500:
I have worked for laptop manufacturers, service laptops and teach IT
(specifically A+ certification and networking courses) at a local
college.
I disagree with the part of your post which stated "components that
are underspecified or are not tested for value accuracy"; but I do
agree with "today's laptops are much more poorly built than older models".

The differences are not components or specifications, but rather what
I call "build quality". The decline in "build quality" comes from
pressure to cut down on cost, weight and size, all of which contribute
to systems that are electrically well designed but which are
mechanically flimsy and of inferior quality compared to the way that
laptops were built 4 to 8 years ago.
I don't know... as computers are always going to get more powerful and less expensive over time. And I am not convinced that there is a decline in built quality either. As laptops have also improved over the years too. Like getting rid of florescent lamps and inverters and trading them for a row of bright LEDs. Which are much more reliable and not as sensitive to shock.

Speaking about not sensitive to shock, we are only a few years away from SSDs replacing old mechanical hard drives. I too also believe this is far better than the older method. And speaking of mechanical hard drives, these too have been improved over the years. Some even sport anti-shock features. They have also increased in capacity and also dropped in price.

Take my old Epson PX-8 built back in 1984. I like to think of it as the first netbook. As it is about the same size and shape. But the display is terrible and it is heavy. Besides it is very limited compared to today's standards. Although it is well built, nonetheless. Although it also cost $2000 (including the RAMDrive and extras) back then. I do love the Epson's keyboard, but for that price you should get a great keyboard. Even then and now though, I would have traded it for one of today's netbooks in a heartbeat. ;-)



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