The 8150 represented the leading edge of a new breed of high-power integrated amplifiers that challenged the hegemony of separates. Part of the trick was its use of an extra dose of Class A bias, lack of compression, and superb channel separation.
Insanely popular, the David Hafler designed 35Wpc was introduced in 1959 yet kept on truckin’ for about 30 years. Easy to modify and renown for its personable midrange, it was often affectionately referenced as the “poor Man’s McIntosh.”
One of many, now legendary designs from Marantz audio engineer Sid Smith, the 8B can be considered the amplifier (35Wpc) that contemplated the modern era of the high end.
Using an implementation of Mac’s original unity-coupled circuit, the MC275 set new standards for low distortion. Able to run as a 150W mono amp or as a 75Wpc stereo amp, it proved so popular that it returned for an encore years after ceased production.
Audio Research D-150
ARC’s D-150 did everything big in 1975. Huge meters on a massive chassis, high heat output from the 6550s, and the kind of power that made them the amplifier of choice for the then speaker of choice, the Magneplanar Timpani 1D.
Blue plate manna from audio heaven, the RB-1090 was the go-to amp for low-sensitivity speakers that presented tractor-sized loads. Rated at 380Wpc with 1kW peaks at 2 ohms, it combined price/power and performance like few amps on the market.
Born in the late 1970s, it was the little integrated amp that could. By keeping it clean and minimalist, blessing it with a sweet midrange and dynamics out of proportion to its modest power, NAD kept buyers coming back for more. And they still are.
Phase Linear 700/400
Bob Carver’s 1970 designs demonstrated that mega-amps driving lower-sensitivity loudspeakers could perform on the same field with lower-powered competitors. Unique for its time were the transformers and output transistors placed on the outside the chassis–an innovation that eased serviceability and reduced operating temperatures.
Mark Levinson ML-2
Before Lexus and corporate branding, before Kim Cattrall, there was Mark Levinson, the man—an original who pioneered a second wave of high-status boutique amplifiers like the ML-2 that defied corporate culture. Levinson help to raise the bar on resolution and power and cost and led the way for dozens of wannabes.
A right of passage—there was more hair pulled out trying to finish these DIY amps. The parts often changed and kits sometimes arrived incomplete but a generation of teenage hobbyists cut their teeth building these components and moving on to their own cutting-edge designs.
The Williamson Amplifier (1947-1949)
Not the first tube amplifier with feedback nor the first with low distortion—Peter Walker had a feedback prototype in the late 1930s and Leak a hi-fi amp before Williamson—Williamson’s designs published in Wireless World in the late 1940s showed once and for all that low-distortion amplification was possible and practical. Along with the McIntosh M50W1, the beginning of modern high fidelity.
This amplifier, developed by Gordon Gow for McIntosh in the late 1940s, was the American analogue of the British accomplishments. With bandwidth from 20Hz to 20kHz and less than 1% harmonic distortion, it had high fidelity in a strong sense and set the stage for the American tube amplifier industry of the 1950s and early 60s.