To anyone who grew up with MP3s and digital downloads, turntables for vinyl records might seem as outmoded as bell bottoms and the three-martini lunch. Despite their long fall from favor, vinyl records are still plentiful, and 2012 figures from the Nielsen organization show that their sales are on the upswing. Turntables to play them on are increasingly available as well, often with the necessary circuitry to convert your collection into a digital format.
Direct vs. Belt Drive
The basic task of a turntable is to spin at a precise and constant speed. If it speeds up and slows down it will cause distortions in the sound, known as "wow" and "flutter." Noise from the turntable's motor can also interfere with sound quality. Many turntables place the motor off to one side, and use a belt to turn the platter. This reduces motor noise, but increases the risk of wow and flutter. Direct-drive turntables connect the motor to the turntable directly, providing more accurate speed control. Professional turntables are usually direct drive, and deal with the noise problem through better engineering and higher manufacturing standards.
Cartridge and Tonearm
Much of a turntable's sound is dictated by the quality of its cartridge and tonearm. The cartridge attaches to the tonearm, and holds the stylus that actually rides through the record's grooves and generates the audio signal. The best are usually very light, because a light stylus creates less noise and therefore a better ratio of signal to noise. The signal-to-noise ration is expressed in decibels, and high numbers -- 70 dB or higher -- are best. Better-quality turntables have a counterweight at the back of their tonearm, enabling you to adjust your "tracking weight" to take full advantage of a better stylus.
The electrical signal generated by the stylus is very small, measured in milliwatts. It's transmitted through the cartridge to the tonearm, and from there through the turntable to its output cables. This signal is much lower than those created by CD players or other components, and it must be boosted up to that level before it can be used. Some stereos have a special input for turntables, with a built-in preamplifier. Some turntables have a built-in preamplifier, enabling them to put out a signal that will work with any amp. Audio purists can attach an external preamp between the turntable and stereo amplifier, maintaining the highest possible audio quality. Depending on the amp or computer sound card you're connecting the turntable to, an external preamp may be a necessity for audible output.
If you're an enthusiast who appreciates the warmth of analog audio as a contrast to the cold precision of digital music, you'll probably make your decision based on the turntable's specifications. If you just want to listen to music on vinyl LPs, some less-technical features will probably be just as important. For example, basic models might offer automatic operation. Place the record on your turntable, push a button, and it will play. Higher-end models are manual, requiring you to place the stylus on the record by hand. Some models are portable or self-contained, with their own speakers, radio tuners and docks for iPods or smartphones.
Analog to Digital
One of the most common user features in modern turntables is analog-to-digital conversion, enabling the transfer of vinyl albums to a number of electronic formats. Some popular models include built-in CD burners. Others provide USB connections, SD card slots, or a dock to transfer audio directly to your iPod or iPhone. A variety of audio-recording programs are available commercially or for free download, cleaning up the sound quality as you transfer your albums. If you're uncertain which technology is best or what accessories you might need, consult the staff at an electronics store such as your local RadioShack.
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