C700 Reference Preamplifier
SOUND PURITY HAS REACHED NEW HEIGHTS
In designing high-end loudspeakers and hi-fi components, TAD has always strived for the perfect fusion of sound image and sound field. It is a relentless approach to achieving the highest level of sonic purity without taking away or adding anything to the original sound intended by the artist. This means that TAD recreates the sonic image and field in which every element of the sound created by an artist or artists is reproduced with unparalleled clarity and definition - exactly where it should be.
The new Reference Series TAD C700 preamplifier follows a long-standing TAD tradition to take sonic purity to new heights. It incorporates a series of uncompromising refinements and improvements to the preamplifier circuitry, dual-mono construction, power supply and vibration suppression techniques down to the smallest detail, setting a new standard by which all other preamplifiers will be measured.
FULLY BALANCED CIRCUITRY AND DUAL-MONO CONSTRUCTION
TAD's goal is to design a world-class preamplifier capable of remarkably accurate signal transfer from input to output. To this end, we have taken extra steps to achieve ultimate uniformity in circuit topology and right and left channel layout. Firstly, the C700's fully balanced circuitry amplifies the positive and negative signal waveforms individually to ensure identical dynamic circuit characteristics for both signals. Second, the wire length and dressing are identical between the positive and negative signal paths and between the two channels, providing an ideal signal path from input to output. Thirdly, the dual-mono circuit design achieves maximum symmetry to provide identical amplification, both electrically and mechanically, to the positive and negative signals and to both channels, resulting in near-perfect stereophonic sound reproduction.
SIMPLIFIED SIGNAL TRANSMISSION
Highly simplified circuit topology eliminates any possibility of signal degradation from input to output
True to TAD's fervent belief that "a signal path with minimal functionality is the surest way to achieve the highest level of accuracy and sound quality", the C700's input signals are amplified by a single stage voltage amplifier before output, after being levelled by the electronic volume control. In addition, a dedicated output amplifier circuit for each of the two line outputs prevents signal splitting and interference from connected equipment from degrading the sound quality. In order to transmit music signals in a straightforward and accurate manner, the C700 does not have a monitor switch for the recording output, as this could have a detrimental effect on sound quality. In addition, the audio pass-through mode outputs input signals from a pre-out jack without changing the signal level, eliminating the need for a switching circuit.
SOPHISTICATED NOISE REDUCTION TECHNIQUES
The dual enclosure design, which separates the power supply from the amplifier unit, is just one of many techniques used to minimise noise for ultimate signal clarity.
The C700's power supply is physically separated from the main amplifier unit. This ingenious design prevents vibration and magnetic flux leakage from the transformer from adversely affecting the audio circuits inside the main unit. The outboard power supply unit houses a large, powerful 400 VA toroidal transformer - not uncommon in power amplifiers, but unheard of in preamplifiers. To increase the purity of the power supply, the transformer's internal coil is connected directly to the power supply circuit, minimising contact with lead wires. In addition, the lead terminals, motherboard mounting terminals and clamping screws are all made from oxygen-free copper, coated with non-magnetic materials to eliminate even the slightest magnetic distortion. All these refinements incorporated into the power supply design enable faithful and accurate transmission of signals, regardless of sudden changes in their level. The combination of the ingenious power supply and the fully balanced circuit design, which eliminates unwanted noise currents, results in noise-free performance.
CONTROL
The control buttons and LED display operate on direct current. The control wires are housed in a central shield to prevent unwanted interference.
In the main amplifier unit, the control buttons, LED display and indicators operate on direct current, minimising their effect on sound quality. The control circuit wires and power supply are housed in a shielded box located in the centre of the cabinet. This design prevents interference with the circuit boards, improves isolation between circuits, and adds to the robustness of the cabinet.
METICULOUS VIBRATION CONTROL
A machined aluminium sub-chassis and three-point support isolators block external vibration and noise, and ensure electrical stability.
The C700's main amplifier circuitry is mounted on a rugged 33mm thick, 15kg sub-chassis precision-machined from pure aluminium ingots to provide excellent vibration control, minimising the effect of external vibrations. The use of pure aluminium ingots provides a stable ground path. In addition, other parts of the cabinet are manufactured with the same level of precision to reduce the effect of external vibration and noise, helping to ensure that music is reproduced with the highest degree of purity and fidelity to the input signal. In addition, the C700's spike-shaped three-point feet ensure mechanical stability on any surface. All these meticulous designs combine to free the C700 from unwanted external influences and allow it to perform to its full potential.
HIGHEST QUALITY PRECISION PARTS
Carefully selected high quality bespoke parts including electronic volume control and high precision ball bearings
The C700's custom-designed electronic volume control features ladder-resistance circuitry that achieves an absolute error of 0.1 dB or less, even at more than 100 dB of attenuation, off-limit attenuation between the left and right channels, and ultra-low distortion of less than 0.0005 % at 1 Vrms input. This volume control is designed so as not to affect the impedance at the input and output terminals, and to provide well-balanced sound even at low volume levels. Independent electronic volume control is provided for each of the left and right channels to ensure uniformity between them, as well as excellent sound-image localisation and sound field reproduction.
The input selector and volume control knobs are each mounted on high-precision 41 mm diameter ball bearings, giving them the smooth, elegant feel you expect from high-end audio components.
ADVANCED OPERATING TECHNOLOGY
Extreme Link allows synchronous control of multiple C700s
Extreme Link allows a master C700 to control multiple slave C700s connected to its MASTER OUT jack, providing a dual-mono configuration for monaural power amplifiers, or three or more channels of sound in a high-end audio or home theatre system.
Independent sensitivity adjustment available for each input
The C700 allows independent sensitivity adjustment for each input terminal, so that listening levels do not vary greatly when switching between different sources.
Made in Japan
years of experience
Press reports
Technical data
| Model | TAD Reference C700 Preamplifier |
|---|---|
| Input connectors | 4x balanced, 2x unbalanced |
| Output connectors | 2x balanced, 2x unbalanced |
| REC OUT connectors | 1x balanced, 1x unbalanced |
| Rated output voltage | balanced 1.5 V, unbalanced 0.75 V |
| Maximum output voltage | balanced 16 Vrms, unbalanced 8 Vrms |
| Rated distortion (T.H.D.) | 0.0015% |
| IHF SN | 120 dB |
| Frequency response | 10 Hz to 100 kHz, -1 dB |
| Gain | 12 dB |
| Analog maximum permissible input voltage | balanced 20 V, unbalanced 10 V |
| Power requirements | AC 220 V to 240 V, 50 Hz/60 Hz (Europe/Asia) |
| Power consumption | 50 W |
| Power consumption during standby | 0.5 W or less |
| Dimensions | Main unit: 450 mm (W) x 150 mm (H) x 440 mm (D) Power unit: 220 mm (W) x 185 mm (H) x 430 mm (D) |
| Weight | Main unit: 29 kg / 63.9 lb Power unit: 15 kg / 33.1 lb |