For Sterling Sound
For decades, audiophiles have debated the relative merits of amplifiers based on tubes versus those based on transistors. And while the debate will surely rage for decades more, one fact is indisputable: tube amps are quietly taking over the high-end category of audio amplifiers. Hundreds of tube amps, with prices starting at about US $1000 and going well up into the tens of thousands of dollars, are now on the market.
Among the tube adherents there is a small but flourishing subculture that loves nothing more than the sound of a specific type of amplifier, called a single-ended amplifier, based on a specific type of tube, called a directly heated triode. If you're not part of the subculture, those terms may sound like techno-babble. Bear with us; we'll get to them in a minute.
For now, consider the factors that are keeping the single-ended amp's following small: the amps are expensive, and they usually put out only 10 watts per channel or less, necessitating the use of very efficient loudspeakers. But two Belgian engineers, Benny Glass and Stephane Kempeneers, are out to change all that.
Their company, Aqua Blue, in Antwerp, has created a pair of kits that let a reasonably skilled solderer build a complete amplifier based on the powerful, legendary 845 tube. The Outerlimit version costs about $7000 (an assembled version is also available for about $16,000; non-European Union customers pay about 20 percent less). A "poor man's" version of the kit that sacrifices some performance costs about $3000--extremely cheap for this sort of amp. The amplifiers put out 33 watts per channel, which is rather high for a single-ended tube amplifier, and enough to drive a wide variety of loudspeakers.
Both versions are single-ended amplifiers, which means that their active devices (the tubes, in this case) are always conducting current and, if there are more than one of them per channel, are always in phase with each other.
The spectacular 845 tube lights up like a 40-watt bulb and was one of several big triodes designed before 1940. It is still in production today for applications like AM broadcasting. It is a directly heated triode, which means that its heater and its cathode are the same thing. The Outerlimit version also uses rectifier tubes of a similar vintage design. These 866 tubes are filled with mercury vapor and glow a beautiful purplish-blue in operation.
Assembling the amplifier could be an ideal multiweekend project for EEs who find themselves staring at a computer screen day after day and long for such quaint pleasures as the smell of rosin and the thrill of probing a circuit by hand. We haven't tried it, but those with the savvy and nerve to follow the Belgians' assembly instructions and check connections that may be sitting at more than 1200 volts should end up with an impressive piece of hardware. But be careful where you put the finished amplifier: it will weigh about 30 kilograms, thanks to its five huge paper-in-oil capacitors, eight chokes of varying values, and two output transformers, each the size of a one-liter bottle. These components, along with the powerful tubes, also put out plenty of heat.
Smart Shoes
Are your running shoes too hard for running on asphalt? Too soft for a dirt track? No matter, because, according to Adidas-Salomon AG, in Herzogenaurach, Germany, the Adidas 1 running shoe will continually adjust the firmness of its heel to make sure it always feels right: softer on concrete, firmer on grass, for example. (Test shoes were not available at press time.)
The preferred firmness of a cushion in the heel is selected when you push either of two buttons on the side of the shoe, one carrying a plus sign, the other a minus. These in turn activate a motor that tightens or relaxes a steel cord to give the heel its variable firmness. Five light-emitting diodes on each shoe indicate the firmness levels.
The hollow plastic cushion in the heel contains a Hall Effect sensor, which reads the strength of an electromagnetic field created by a magnet near the bottom of the heel. As the runner's foot strikes the ground and the plastic cushion is compressed, the sensor measures the change in field strength. It sends this data to an embedded 20-megahertz microprocessor in the shoe's arch, which calculates to within 100 micrometers just how much the cushion has been compressed, and adjusts the cord tension to maintain a constant level of firmness no matter what you're running on. This cycle of sensing, measuring, and adjusting happens 10 000 times a second. You won't notice the cord's tension changing until you start moving, because the motor is activated only when the foot is in the air. This ensures that it is not wasting energy by fighting against the runner's weight.
The Adidas 1 is expected to hit stores in December.
Sony Digital Player Takes On The Ipod
The iPod, from Apple Computer Inc., Cupertino, Calif., is the 800-pound gorilla of digital music players. Its capacious storage and ease of use have set the bar for anyone attempting to enter this lucrative market: iPod sales are sure to top the US $1 billion mark this year. Now Sony Corp., Tokyo, is trying to raise the bar--and grab a chunk of that market--with the VGF-AP1, also known as the Vaio Pocket. Not just a music player, the device will also allow users to browse album covers or photographs downloaded from a digital camera on its 2.2-inch color liquid-crystal display.
To control its player, Sony has come up with a new style of interface. It eschews the minimalism that characterizes the iPod, on which a single touch-sensitive wheel controls all player functions in the latest generation. Sony's interface is called Grid Sense: a 5-by-5 grid of buttons just to the right of the display is used to navigate through menus organized by song title, artist, album, genre, date, or time of day a song was last played, and most-played songs. Each of the rubber-covered bumps is mapped to the corresponding section of the screen, so the function of any given bump relates to what is shown on the screen. Using this arrangement is quite similar to operating the automated teller machine at your local bank, where each of several buttons along the two sides of the display correspond to whatever function is displayed next to it onscreen.
Along with the ability to display photographs, the Vaio Pocket also bests the iPod in battery life. The newest iPod goes for 12 hours on a single charge of its internal battery; Sony claims the Vaio Pocket will keep the music playing for 20. However, the iPod still wins on price, at $400 for the 40-gigabyte version versus the Vaio Pocket's $500.
Handheld-to-handheld Combat
Sony Corp., maker of the PlayStation 2, the most popular video game console on the market, is going after the handheld game market, which has been all but cornered by Nintendo Co.'s Game Boy.
From Tokyo comes Sony's PlayStation Portable, or PSP, which debuts in March 2005. It is aimed at the same group of 8-to-15-year-olds who have snatched up 50 million units of Nintendo's Game Boy Advance since its introduction in 2001, plus the horde of young adults targeted by violent PC and console games such as the immensely popular Grand Theft Auto series and sports titles such as NFL Live and NBA Street.
The new Sony handheld houses a small, powerful computer whose 333-megahertz processor nearly matches the speed and performance of the VCR-size PlayStation 2. Its memory is also comparable--32 megabytes of random-access memory and 4 MB of embedded dynamic RAM. With such memory, Sony hopes developers will offer more sophisticated games than have ever been possible for Game Boy.
The 170-by-74-by-23-millimeter pocket game machine has a 4.3-inch color liquid-crystal display, compared to the Game Boy's 2.9-inch display. The basic game controls are laid out much as they are on PlayStation 2's handheld controller. Users can turn off features, such as wireless access, to conserve battery power.
But Nintendo is not sitting idly by in Kyoto. It has a new handheld video game player of its own. The Nintendo DS, for dual screen, flips open like a clamshell, revealing two 3-inch screens, one above the other, whose functions depend on the game. In a racing game, for instance, one screen can display the driver's point of view from inside the car, while the other provides a view that pinpoints the location of the other cars racing along the track. For, say, a football game, the screens can be made to work in tandem to show the entire field at once.
The standout feature of the DS is that the bottom liquid-crystal display is actually a touch-screen that can be manipulated with a stylus or a finger. Players can guide game characters by dragging the included stylus across the screen.
Nintendo also holds a strong advantage because it has an extensive catalog of Game Boy titles geared toward kids: a slot on the DS lets it play old favorites that children already own, removing the need to buy a new library of games.
But the Sony PSP is clearly designed with more than gaming in mind, which should improve its chances with adults. For instance, it can play 60-mm-diameter optical discs (called Universal Media Discs) that hold up to 1.8 gigabytes. That is enough to store a game, or 200 to 300 songs, or two hours of DVD-quality video. The device also has ports for a Wi-Fi wireless local area network (IEEE 802.11b), USB 2.0, and infrared connections. It also accepts data from Sony's proprietary Memory Stick solid-state storage media. These features allow online gaming, downloading of music and film clips from a PC, connection of PSPs for multiplayer games, or attachment of peripherals to enhance the PSP's capabilities.
The Nintendo DS has wireless communications, too. And it allows DS users to play against each other and send text messages wirelessly by tapping on a keyboard displayed on the device's touch-screen. Like the PSP, the DS can connect with others of its kind whether they're in the same room or, via the Internet, thousands of miles away.
Two screens make the DS thicker and heavier than both its predecessor, the Game Boy Advance, and the PSP. But the Nintendo maintains one distinct advantage over Sony's handheld challenger. The DS will sell for about US $150, while the PSP will sell for about $400.
Taking Your Security With You
Got sensitive information in your workstation's files at the office? Do you worry when you must step away for a few minutes that someone could snoop around too easily? If so, you might want to safeguard your system with the USB Wireless Security Lock. It works like a car's remote door opener. Walk away from your computer and the machine instantly locks up, making its contents inaccessible to anyone else. When you return, the computer is automatically available.
The secret is in a round transmitter you carry in your pocket. It's powered by a 3-volt battery and has a range of about 2 meters--enough to signal a receiver dongle plugged into the computer's USB port to keep the machine turned on. Walk out of range, and the dongle loses the 315-megahertz signal and locks the computer. This scheme is safer than a password protection system linked to a computer's screen saver, which is usually set to turn on after a few minutes of inactivity. That leaves a window of time during which someone can fiddle with your computer.
If the transmitter is lost or the dongle is removed, a series of user-selected passwords, which only you will know, allows you to regain access to your machine.