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Old 19th March 2013, 10:21 AM   #36881
SY is offline SY  United States
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Exactly so. If you're marketing to a fashion niche, besides the "story," you have to make something that looks and feels expensive, performance aside. There's are better and worse ways of accomplishing that. If the waste of an inefficient process is part of the "story," then there's not much to be done.
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Old 19th March 2013, 10:23 AM   #36882
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Quote:
Originally Posted by RNMarsh View Post
Here is a photo
Is it for plasma confinement Richard?


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Originally Posted by simon7000 View Post
Ed, check if the noise is due to the probe’s ground clip pick-up point.

On a side note, long ago, you had asked me (I saw your post with a great delay) what I find as an alternative to a choke input psu.
What I find that can work as such, is cascaded CRC.
Multistage, each stage with different time constant and C progressively increasing towards the load side.
Apart for higher harmonics decreasing more, the arrangement deals well with the problem of rectification frequency ripple (2xmain’s freq.) increasing in amplitude when the amplifier (that the psu is feeding) amplifies low frequency music (sustained notes) content.
Typical PSUs with a lot of C after the bridges and not CRC arranged, are vulnerable to this.
See attached some measurements on a psu of a well regarded power amp (amp is 2x150W/8R. In these measurements, I drive only one channel and up to 100W. I probed on the + side of the psu).
To see the effect, I link two oscilloscope screenshots taken years ago from a psu of the same kind of another amp. http://www.diyaudio.com/forums/attac...modulation.jpg

George
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Last edited by gpapag; 19th March 2013 at 10:44 AM.
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Old 19th March 2013, 11:37 AM   #36883
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Near all famous designers and architects agree on one thing: a good design is when the form is a natural consequence of the function. It is the same for ideas: " Ce qui se conçoit bien s'énonce clairement."
It is always amazing to see how beautiful are objects with high technical constraints, planes, submarines, rockets, race cars, when no marketting departments impose some stupid fashion specifications.
It is always interesting to see how the best printed boards designers (we have some on this Forum, like Sir Alex mm), when they took in consideration all the technical aspects (ground issues, symetry, parasitic inductances etc.) produce very nice looking PCBs.
There is a general law in the universe: Everything follow the easiest way. Perfect combination of "easiest" everywhere brings to simplicity and economy.
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Old 19th March 2013, 11:53 AM   #36884
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Christophe,
My way of thinking exactly. Design should follow function and function should dictate design. Or as we say, go with the flow, you can not beat nature, nature always wins in the end.
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Old 19th March 2013, 12:21 PM   #36885
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It is always amazing to see how beautiful are objects with high technical constraints, planes, submarines, rockets, race cars, when no marketing departments impose some stupid fashion specifications.
Easy to say they're not, if the degree of design liberty is limited to the shape of a window or a wing tip.
Try throwing a brick through the air with minimal thrust SFC.

Styling may be forced to play an inferior role in airplane, rocket, and race car design, but aesthetic appeal sells there just as in any other line of business.
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Old 19th March 2013, 02:02 PM   #36886
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High opinions, from 'Monday morning quarterbacks'. '-) A 'sealed' construction is a necessity for the best operation of the CTC Blowtorch. It keeps the impurities from the outside air from getting inside the unit. It keeps the inside, dust free. It keeps (once it is fully warmed up) changes in temperature from adding further 1/f noise or creating dynamic offsets. (Just blow on a Vendetta Phono board sometime or just lift the lid while it is connected to test equipment.) The only thing that I regret is not adding some sort of sulfur 'trap', something recommended to me by Ed Simon. (Next time!)

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Old 19th March 2013, 02:05 PM   #36887
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Styling may be forced to play an inferior role in airplane, rocket, and race car design, but aesthetic appeal sells there just as in any other line of business.
Yes, it is true. Easy to see how aesthetic was different, during the spatial race between USSR and USA. Our technical approaches are deeply influenced by our environment, art, culture, etc. But it is in an unconscious and natural way. Like trees tend to look different under different winds. Not marketing trying to sell apples for oranges.
In a way, i believe science fiction deeply influence science, like language influence our way to think.
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Old 19th March 2013, 02:11 PM   #36888
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Here is an example of what the manufacturer named inter-locking.
Milled panels, but they slide into eachother at the edges. (aka groovy tongue)

Pleasure without the pain.
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Old 19th March 2013, 02:17 PM   #36889
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High opinions, from 'Monday morning quarterbacks'. '-)
And you are surprised to be flamed, sometimes ?
Dust or thermal effects are nothing to do with "plain machined aircraft grade aluminum".
My 4 CPUs 5Ghz computer is full of dust, enormously ventilated, with huge dynamic temp differences, and run like a clock.
It was cheap, too.
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Last edited by Esperado; 19th March 2013 at 02:19 PM.
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Old 19th March 2013, 02:17 PM   #36890
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Boeing has solid blanks cast for small parts such as wings! If you look at the economics, the aluminum blank costs around $1.65 a pound and the chips sell for $.95. A press release I quickly found mentions a bit about their milling capability.

"Commercial Airplane Group's newest fabrication facility today began turning out the first components this massive plant will make to support production of the company's jetliners, Boeing (NYSE: BA) announced today.

The approximately 100 employees on duty began production of a wing skin panel for a Boeing 747 and a Boeing 767 upper panel stringer using huge milling machines that will eventually make parts for all Boeing models except the 737. Production of parts for Boeing's newest jetliner, the 777, is scheduled to begin at the Frederickson site in mid-summer.
Called Skin and Spar South, the 935,000-square-foot (86,861- square-meter) facility is located in Frederickson which is about 16 miles (25 km) southeast of Tacoma and 44 miles (70 km) from Seattle.
Part of Boeing Commercial Airplane Group's Fabrication Division, the Frederickson facility was designed to supplement a wing skin and spar factory in Auburn, Wash. where Boeing's Fabrication Division is headquartered.
Skin and Spar South will eventually employ 350 to 400 workers when it reaches full production by the end of 1994.
Equipment in the Frederickson facility includes milling machines that measure up to 270 feet (82 meters) and are capable of milling parts 105 feet (32 meters) long.
Skin and Spar South is the first facility to be activated at Boeing's Frederickson site. Last November ground was broken for a second facility, a 432,000-square-foot Composite Manufacturing Center (CMC) which will fabricate parts made of carbon fiber reinforced plastics. The CMC is scheduled to begin operations in February 1993.
Boeing has also announced plans for three more expansion phases to build various manufacturing and office facilities over a period of about 20 years. Formal initiation of each additional phase will depend on business conditions and market demand.
-0- 4/15/92
/CONTACT: Mike Broom of Boeing, 206-931-5834/
(BA) CO: Boeing Commerical Airplane Group ST: Washington IN: AIR SU:
"
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