Many of you have asked us how "special" derivative TVs differ from the standard models in a manufacturer's line.
Generally, these sets are made to hit specific retail price points during promotional shopping periods. They allow bigger-name companies to compete on price with lesser-known secondary or tertiary TV brands. Because the derivative sets are lower-priced, they typically have lower specs and lack some features found on standard models.
Panasonic, for example, is offering a 50-inch 720p plasma, the TH-50PE8U, at Best Buy and Kmart. Compared to the standard TH-50PX80, the set has a lower claimed contrast ratio—10,000:1, instead of 15,000:1— and one less HDMI input (there's no front HDMI input as there is on the 50PX80). There are also slight cosmetic differences.
Samsung has several special models—A300-, A400- and A500-series sets—that are widely available this week. These sets also have lower claimed contrast ratios, fewer HDMI inputs, and fewer features than its regular line. For example, a new 40-inch 1080p LCD, the LN40A500, has joined the standard LN40A550 model at some retailers. Compared to the regular model, the A500 has a lower contrast ratio (20,000:1, instead of 30,000:1), only one HDMI input (the A550 has two), and no S-video input (it does have a PC input, which isn't included on the A550). It also lacks a picture-in-picture and WiseLink Pro (for accessing photos and music stored on a removable flash drive) features, and weighs 15 pounds less.
Derivative models typically sell for at least a few hundred dollars less than standard models, but in this season of ultimate volatility, it's hard to pin down pricing. We can't comment specifically on the performance of derivative models because we test standard products that are available widely, and not limited to specific promotional periods or retailers. However, you can use our Ratings of LCD and plasma TVs (available to subscribers) to see how similar sets from these manufacturers have performed.
—James K. Willcox