Tube Power Amp Reviews

Not only does the venerable vacuum tube refuse to lie down and die, as everyone predicted when audio went solid-state; it continues to deliver better performance than anyone had imagined it could. Only a few years ago, we could characterize "the tube sound" as being sweet but soft at the high end, rich but loose in the midbass, deficient in deep bass, and bright and forward, usually with excellent reproduction of depth. Since then, we've seen the introduction of what might almost be called a new generation of tube amplifiers, which rival solid-state units in those areas where tubes used to have weaknesses, but have given up little of the tube's sonic strengths.

Few people in the high end know the difference between glorious excess and wretched folly as well as Harvey Rosenberg. Harvey's audio equipment always strives towards the glorious folly of providing the most romantic sound possible with modern technology. This may explain why his relatively small company, New York Audio Laboratories, can build an amplifier like the Futterman OTL-1, which costs a glorious $12,000 a stereo pair and actively competes for the title of best amplifier in the world.

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 would appear that there are still people out there who are unaware that this is the age of the transistor. Not only are tubed amplifiers not vanishing from the face of the earth, they are proliferating. Audio's equipment directory for 1977 listed three tubed power amplifiers. The same directory for 1984 lists over 30 of them, and the Quicksilver amplifier is not even included!