Despite advances in audio reproduction technology, the design and sound of tube amplifiers have changed little over the decades. So much so that audiophiles searching for the absolute sound find themselves going back to the classic amplifiers of the ‘50s and ‘60s, the so-called golden age of vacuum tube equipment. Here are six legendary tube-based amplification systems that continue to beguile discerning listeners.
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HARMAN KARDON CITATION II 60 WATTS PER CHANNEL STEREO POWER AMPLIFIER. Designed from a professional sound engineer’s perspective, Stewart Hegeman’s 1961 Harman-Kardon’s Citation II featured a very high (for its time) 60W per channel output, low distortion, and high bandwidth. The output transformers built by the Freed company in New York were huge, well-potted units capable of very wide response characteristics. According to the Harman Kardon catalog, only the highest-grade core materials available were used, which lowered the effect of core distortion to a region well below the limit of human hearing.
FISHER KX-200 40 WATTS PER CHANNEL STEREO INTEGRATED AMPLIFIER. The Fisher was the brand name for hi-fi electronic equipment manufactured in New York by The Fisher Radio Corp. during the golden age of the vacuum tube. Founded by Avery Fisher, the company made the FX-200 in the early 1960s, which combined a pre-amplifier section with a power amplifier. They were also sold with optional wood cabinets and had aluminum faceplates instead of the usual brass.
MARANTZ MODEL 2 40-WATT MONOBLOCK POWER AMPLIFIERS. Designed by Sidney Stockton Smith, a trained electrical engineer who later stayed on to become chief engineer at Marantz, the Model 2 was introduced in 1956 as the first power amplifier made by the company. Today, mint-condition monoaural amplifiers are hard to come by, especially since you need two of them to operate in stereo. Being the first amplifier made by Marantz, it is highly collectible due to its rarity and exceptional musicality.
MARANTZ AUDIO CONSOLETTE MONO PREAMPLIFIE. Built in 1953 by Saul B. Marantz, founder of the audio company named after him, the Audio Consolette was sold under Harvey Radio based in New York City. Legend has it that Marantz could not find anything that sounded good enough in those days, and decided he would have to build his own equipment. It was the Marantz company’s first product, later to evolve as the Model 1.
EICO HF-85 STEREO PREAMPLIFIER AND HF-60 AND 60-WATT MONOBLOCK POWER AMPLIFIERS. Eico produced hi-fi products in the early ‘50s to the mid-‘60s. They included a line of tuners, preamplifiers, and amplifiers, available both in kit form or fully assembled. EICO is best known for “monoblock” amplifiers such as the HF-60, two of which were required to power stereo loudspeakers. The Eico HF-85 pre-amp featured channel separation, separate controls for each channel, and more input switch selection choices than was standard in its time.
QUADII 15-WATT CLASS A MONOBLOCK POWER AMPLIFIERS. In 1936, Peter J. Walker founded Quad Electroacoustics Ltd. in London. It was initially called S.P. Fidelity Sound Systems. “Quad” is an acronym for “Quality Unit Amplifier Domestic,” which described the QUAD I amplifier. In 1983, the company later changed its name to QUAD Electroacoustics Ltd. Made between 1953 and 1970, QUAD II’s output stage set it apart from amplifiers made during the time.
DYNACO MK. IV 40-WATT MONOBLOCK POWER AMPLIFIERS. Considered a good match for the PAM-1 preamplifier, the Mk. IV was released in 1960 as a monophonic power amplifier in either kit form or as factory-assembled units. More than anyone else, Dynaco’s founder, David Hafler was interested in selling DIY kits, which the average hi-fi enthusiast could assemble using a supplied schematic diagram, a pre-tested circuit board, and commonly available components.
DYNACO DYNAKIT PAM-1 MONO PREAMPLIFIER. Dynaco’s first preamplifier was designed by Ed Laurent and introduced in 1957. An added DSC-1 Stereo Volume Control Unit (not shown) allowed for two PAM-1 units to be combined for producing stereo amplification. Unlike earlier preamplifiers, the PAM-1 was relatively inaudible in the musical reproduction chain. The unit also boasted of being unaffected by the setting of the volume control—in sharp contrast to other preamplifiers at the time whose performance deteriorated at normal volume settings.
Photographs by Philip Sison
This story first appeared in Vault Magazine Issue 5 2012.