QUAD Vacuum Tuber Amplifier Systems QUAD II-FORTY - Manual (Page 9)

‘the closest approach to the original sound...’ has been a
Quad philosophy since 1936. More than just a slogan, it
underlies the company’s commitment to producing the
finest audio equipment, capable of reproducing all the
elements and emotion of a live performance.
This is a faithful reproduction of the original,
the new Quad II Classic offers audiophiles the
chance to recreate the spirit and atmosphere
produced from one of the most famous amplifiers
in audio history.
The original Quad II was first launched in 1953,
designed by Peter Walker. At the time, many of
his contemporaries were also producing good
quality valve amplifiers. The Quad II looked, in
comparison, very simple and unassuming, but
its performance was far beyond that which its
diminutive dimensions might suggest.
The property which set the Quad II amplifier apart
from other amplifiers of the time was its output
stage. It was arranged such that the cathode
coupled circuit emulated the performance of
triode operation, but with the size and efficiency
characteristics of pentode operation. It was this
breakthrough that ensured the Quad II was to
remain in continuous production until 1970.
Peter’s circuit, notably the design of the output
transformer, has become the stuff of legend amongst
electronics engineers. Studied and analysed by
the finest minds in the industry, the elegance
and coherence of the design is still regarded as a
reference today.
Given the quite modest components of the day, he
was able to engineer something which was quite
literally greater than the sum of its parts.
The Quad II classic has been recreated accurately
with output valves and input valves the equivalent
of those used in the original design. The same
balancing act has been employed to ensure the same
wealth of detail and gentle tone of the original.
The output valves produce around 15w per channel,
operating in Class A which, although slight by
modern standards, allows a gloriously sweet
and refined sound with appropriately matched
contemporary loudspeakers.
II-classic
The Quad
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