P R O U D L Y M A D E I N T O K Y O
Advanced Output Buffer Circuitry Delivers Stronger Performance
to Drive Power Amplifiers — ESOTERIC-HCLD*
In its function as a line driver, the preamplifier must have the ability to fully
drive the power amplifiers in a way that faithfully conveys music signals that
have an extremely wide dynamic range, extending all the way from
pianissimo to fortissimo. The key to achieving this is having a circuit with
both a high current drive capability and high speed. The C1’s output buffer
circuitry utilizes high-performance components to deliver a very high level
of current drive, together with an exceptionally high slew rate of 2,000V/µs.
Each output has its own independent drive circuit, and for the XLR outputs,
the instantaneous output current capability is maximized by the use of fully
symmetrical circuitry for both the hot and cold phases.
The C1 employs an EDLC* Super Capacitor array located close to the
output buffer circuitry to function as a highly stable power source. Its
compact physical size belies the fact that it provides the extraordinary
capacity of 100,000µF (0.1F) for each channel, facilitating very high levels of
instantaneous output power, which in turn provides strong and solid bass
reproduction. With the integration of these two technologies, the C1
recreates a breathtaking level of audio reality by preserving the musical
dynamics that would otherwise be lost if smaller current transmission
levels were employed between the preamplifier and power amplifiers.
*HCLD = High Current Line Driver *EDLC = Electric Double-Layer Capacitor
C i r c u i t D e s i g n
Precision Controls Offer Outstanding Operational Feel
The C1’s input selector and volume knobs are machined from solid blocks
of aluminum. The use of a VRDS drive mechanism bearing system for the
control shafts enables silkily smooth rotation with absolutely no mechanical
play in their movements. Rotational torque has also been fine-tuned to
provide the luxurious feel of a precision analog control, in keeping with this
top-of-the-line preamplifier.
Other Important Features
Five preset volume curves permit selection of the most comfortable
operating feel for the control.
Adjustable individual input gains allow differences in volume between
sources to be minimized. (Range: ±18dB; 0.5dB steps)
Adjustable left and right channel volume balance control.
(Range: ±6dB; 0.5dB steps)
Selectable phase inversion can be individually set for each source.
'RCA 2' terminal permits switching between normal line output and
AV-through output, providing added convenience for systems which are
operated in both AV surround and pure two-channel modes.
High-quality aluminum finish remote controller can also be used to operate
any of Esoteric’s superb line of Super Audio CD players.
Source component name displays can be programmed using the remote
controller.
Dimmer, mute, and auto-display-off functions also provided.
A d v a n c e d F u n c t i o n
Monoblock Preamp Module
XLR1
XLR2
XLR1
XLR2
XLR3
RCA1
Input Buffer
(Balanced)
Input Selector
HOT
COLD
Phase Inverter
Volume Control Amplifier
Input Amplifier Board
Output Amplifier Board
HCLD Output Buffer
HOT
COLD
HOT
COLD
HOT
HOT
HOT
COLD
COLD
COLD
HOT
COLD
RCA2
RCA1
RCA2
HOT
COLD
HOT
COLD
Relay
Differential Amp
Ultra–Low-Noise Logic Control
The logic control section is built into the front panel and is totally isolated,
both physically and electronically, from the preamplifier module by the use
of an optocoupler. The logic control further ensures low-noise operation by
completely shutting down when not in actual operation, totally eliminating
any possible influence on the C1’s audio circuitry.
All sections of the amplification circuitry are fully balanced, with the input buffer, volume control and
high-speed output buffer laid out three-dimensionally to achieve the shortest possible signal paths. The
C1’s DC power supply provides a clean and stable output to each preamplification section, ensuring that
the power amplifiers maintain full control of the loudspeakers, while at the same time preserving the
music’s delicacy and dynamics.
Fully Balanced Configuration
The C1’s source signal is first received by the dedicated buffer amplifiers
integrated with each of the five inputs (XLR × 3, RCA × 2), and the circuit
configuration is balanced at each stage from there on. Through the
elimination of common-mode noise and the reduction in circuit
impedance, a pure signal, free from noise, is fed to the gain amplifiers via
the shortest possible path.
The C1’s volume control features the Esoteric-QVCS.* This employs four
precision switched resistor ladder networks, which change in unison when
the volume knob is rotated. This arrangement allows the signal paths for
the left and right channels and the positive and negative phases to be kept
totally independent and as short as possible. Consequently the sound has
superb clarity, excellent channel separation and a highly accurate phase
characteristic.
*QVCS = Quad Volume Control System
Main Unit — Underside
Mute
Relay
Mute
Relay
