Audio Research DAC3mkII
¥ 750,000 (around 1997)
Commentary
D/A converter using vacuum tube amplification.
The analog output stage uses a highly reliable twin triode 6922 developed for high-frequency circuits in the VHF band.
We are also pursuing high-speed transmission through a balanced circuit with class-A operation.
The DAC circuit uses a Δ ∑ 1-bit differential converter manufactured by Crystal Semiconductor.
A wide-band dual PLL circuit that combines two voltage-controlled crystal oscillators provides strong relocking of input data and eliminates harmful jitter.
The sampling frequency is automatically adjusted to 44.1 khz, 48 khz and 32 khz.
The circuit configuration is based on Audio Research's top-of-the-line preamplifiers.
A large toroidal transformer completely separated from the digital system, a high-speed regulator, and a unique constant current source realize stable operation of the balance circuit, and a pure signal is sent out while canceling common-mode noise.
The power supply circuit includes two discrete regulators and eight IC regulators, including the digital system of the independent transformer.
The chassis is treated with appropriate damping to reduce sound quality degradation due to mechanical resonance and interference.
In addition to the ST-High-Speed Optical Link and TOS link, the digital input / output is equipped with four total Route 3 ports of BNC coaxial for switch selection and AES/EBU balanced XLR. In addition, there is one TOS link direct optical output port.
One XLR-balanced and one RCA-unbalanced analog output can be used simultaneously.
The absolute phase can be switched at any time using the Normal/Invert switch on the front panel.
Equipped with an auto mute circuit for approximately 15 seconds when power is turned on.
The gold-plated input / output terminal has a special structure that does not generate shock noise when inserted or removed.
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Model Rating
| Type | D/A converter |
| Frequency characteristic | 0.1 Hz to 20 kHz ± 0.2 dB |
| Signal-to-noise ratio | 90 dB or More (No Acoustic Compensation, 1 Hz to 20 kHz) |
| Distortion factor | -86dB (0.005%, 1 kHz) |
| Channel separation | 120dB(1kHz) |
| Phase deviation | ± 0.5 ° (20 Hz ~ 20 kHz) |
| Digital input | ST Type Light TOS Link Light BNC Coaxial / 75 Ω (SPDIF), XLR balanced AES/EBU, * switch selection |
| Input format | Fs : 44.1 kHz, 48 kHz, 32 kHz |
| Resolution | 18-bit maximum |
| DAC | 64 x Oversampling, delta-sigma 1 bit |
| Analog output | Unbalanced : 1.55 Vrms (+ 5 dBV) Balance : 3.00 Vrms (+ 11 dBV) |
| Output impedance | Unbalanced : 200 Ω Balance : 400 Ω |
| Digital output | TOS Link Light : 1 system |
| Output phase switching | Digital inversion |
| Pwer | 100 VAC, 50Hz/60Hz |
| Power consumption | 55W max. |
| External dimensions | Width 480x Height 134x Depth 336 mm (Including Handle) |
| Weight | 6.9 kg (Body) 12.3 kg (when packed) |
| Attachment | One BNC-RCA jack conversion adapter |
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