The D-250 is the flagship of Audio Research's power amplifier range and, at 250 watts per channel, is the most powerful all-tube stereo amplifier currently available in the US. Under the circumstances, then, it is not surprising that it should also be one of the heaviest and largest.
Many audiophiles who have only recently subscribed to Stereophile will be surprised to find that those clunky, heat-producing, short-lived tubes that reigned up through the mid-'60s are still Executive Monarchs in the mid-'80s. Why, for Heaven's sake? Because, despite everything, people like them.
The Audio Research D-160B has been heavily modified since the D-160A, and uses the same technology as the D-70, D-115, and D-250. It embodies William Z. Johnson's latest transformer and power supply designs, his latest choice of capacitors and resistors, and the same independent regulation of screens, drivers, and front end. D-160s and D-160As can be converted to D-160Bs for $1500.
It says something for the state of technology that, after a quarter of a century, there still is no authoritative explanation for why so many high-end audiophiles prefer tubes. Tubes not only refuse to die, they seem to be coming back. The number of US and British firms making high-end tube equipment is growing steadily, and an increasing number of comparatively low-priced units are becoming available. There is a large market in renovated or used tube equipmentI must confess to owning a converted McIntosh MR-71 tunerand there are even some indications that tube manufacturers are improving their reliability, although getting good tubes remains a problem.