With the 1996
introduction of the Anniversary Reference Triode (ART), conrad-johnson
established a benchmark for line-stage preamplifier performance that reigned
supreme for most of a decade. Reviewers were unanimous in their praise,
proclaiming it the finest sounding preamplifier ever manufactured. In 2004, the
ACT2 line stage brought new materials technology and refined power supply design
to the composite triode circuit pioneered by the ART, once again elevating the
state of the art. As has been our tradition at conrad-johnson, these
technological advances are now offered in a more cost effective near state of
the art design, the CT5 composite triode preamplifier.
The composite
triode circuit is a conceptually simple design—based on creating a single
“super” triode by paralleling sections of individual tubes. In this way, the
entire amplification circuit can be reduced to a single active stage, without
buffers or feedback. Any active circuit element will color the sound, whether
the element is an amplifier or a buffer stage. By designing a line stage
consisting of a single composite triode, we are able to reduce the circuit to
the absolute minimum of a single active element. The result is an astonishing
improvement in dynamics and dynamic shadings, as well as focus.
In the
CT5, the composite triode is comprised of two paralleled sections of ultra-high
transconductance miniature twin-triode tubes. This circuit achieves a
sufficiently low output impedance to drive most interconnect/amplifier
combinations while eliminating any circuit element that might compromise its
sonic purity. To realize the full potential of this amplifier stage, it is
powered by a sophisticated discrete voltage regulator designed to completely
isolate the audio signal from the power line.
All control functions of
the CT5 operate through microprocessor-controlled relays. For the level control,
the relays select combinations from a network of precision, low-noise metal foil
resistors to effect loudness and balance changes in 100 steps of approximately
.7dB per step. All switching and adjustment can be controlled by the unit’s
remote control. A Theater mode, which passes the input signal through at unity
gain, makes it simple to incorporate the CT5 into a high quality home theater
system without compromising its two-channel performance.
Like its bigger
brother, the ACT2, the CT5 is constructed from the highest quality, carefully
selected parts for unrivaled sonic performance and reliability. The same CJD
Teflon capacitors that distinguish the ACT2 are used in the CT5 for output
coupling and post-regulator power supply storage. All other capacitors in the
audio circuits and related power supplies are polypropylene or polystyrene, and
the resistors in these circuits (including the level control) are special low
inductance, high-precision laser-trimmed metal foil resistors. Switches are
sealed relays with gold-plated silver contacts. Input and output connectors are
premium quality custom machined parts.
In our quest to recreate the glory
of music without compromise, we at conrad-johnson are dedicated to bridging the
gulf between craft and art to create audio amplification components that do
credit to music performances. Through meticulous engineering, careful
specification of only the finest available component parts, and a painstaking
attention to construction, we have created what we feel is a line-stage without
rival in its class.
