QUAD Vaccume Tube Amplifier Systems - Manual (Page 12)

12
II-classic
The Quad
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.