Audio-GD - D-28.38 Discrete Balanced ES9038 PRO DAC Pre- & Headphone Amplifier
The D28.38 or simply D-28 by Audio-GD is an all-in-one offering a superior DAC with a discrete headphone & pre-amplifier. Fully balanced and discrete (transistors) deign with analogue non-feedback Class-A output stages.
It uses the prestigious ESS ES9038PRO DAC chip,featured with praised Hyper-stream II technology which can support audio streams up to 384kHz / 32bit (PCM) and DSD512 (native DSD decoding).
The front display offers a control panel for easy access to all configurations options including digital stream decoding (reconstruction filters, clock strategies .. .etc).
| Marque: Audio-GD |
| Product Type: Amplifiers with DAC |
AUDIO-GD D28.38
HIGHLIGHTS
- Discrete pre- & headhpone amplifier
- USB Crystek clocks
- ES9038 100Mhz Accusilicon AS318B clock
- Remote control (plastic)
- Aluminium Remote Control (Optional)
- Balanced XLR & Single Ended RCA analog inputs
- Balanced XLR & Single Ended RCA analog outputs to power amplifier or active speakers
- ESS Latest ES9038PRO flagship DAC
- USB / HDMI I2S DSD Native 512?DxD and PCM 32Bit /384KHz
- Linear power supply modules, in total 10 double stage PSU groups
- Headphone output :
- 1500 mW @ 100 ohm (per channel)
- 9500mW @ 25 ohm (per channel)
- Pure class A with H / L gain control
- Digital settings configurable from menu front
DIGITAL INPUT
- 1. USB input.
- 2. HDMI I2S input
- 3. Toslink optical SPDIF input
- 4. RCA coaxial SPDIF input
ANALOG INPUT
- 5. RCA
- 6. XLR (balanced)
OUTPUTS
Line outputs can be set to variable or fixed (DAC MODE)
- Mini ACSS balanced
- XLR balanced
- RCA single ended
- Headphone (4-pin) XLR balanced
- Headphone 6,3mm jack single ended
TECHNCIAL SPECIFICATIONS
| SPECIFICATIONS | |
|---|---|
| Output Power (balanced) | 9500mW / 25 ohm 8000MW / 40 ohm 3500MW / 100 ohm 1200MW / 300 ohm 600MW / 600 ohm |
| Output Power (single-ended) | 3600mW / 25 ohm 2500mW / 40 ohm 1100mW / 100 ohm 400mW / 300 ohm 200mW / 600 ohm |
| Gain | H: + 20DB L: + 10DB |
| Clocks | Crystek for USB Accusilicon AS318B For ES9038 |
| Output Impedance | 2 ohm |
| Output Level | Headphone Output: 19V RMS (balanced, max) Preamp Variable (symmetrical): 10V RMS Variable Preamp (RCA): 5V RMS CHA: 2MA + 2MA |
| input sensitivity (analog) | 0.7V to 5V RMS (RCA) 0.7V to 10V RMS (XLR) |
| input sensitivity (digital) | 0.5 Vp-p (75 Ohms, Coax) 19 dBm (Optical) |
| Supported systems (USB) | Windows, OSX, Linux, ISO, Android (USB2.0) |
| Supported Sampling Rates | PCM (USB) / I2S: 44.1kHz-384kHz DSD (USB) / I2S: DSD64-512 Coaxial: 44.1kHz-192kHz Optics: 44.1kHz, 96kHz |
| Power supply | 220-240V AC 50/60 Hz |
| Power consumption | 33W |
| Weight | 5.5KG |
| Dimensions | W240 X L360 X H80 mm |
| Included |
|
Shortest signal path
The D-28 applies the newest ESS ES9038Pro high-end Sabre D/A chip, it can support up to 32 Bit/768 KHz input. The special Audio-GD ACSS circuit naturally works in current mode, it can transfer the ES9038Pro current signal to the output and implement the I/V conversion in current mode in one ACSS amp. This ACSS amp only have one current gain stage, the ES9038Pro output signal only goes through one stage which is very short and best signal path to deliver the clearest and detailed sound!
ACSS is a non-feedback specific Audio-GD technology, designed with fully discrete amplifiers. ACSS offers most neutral with very low distortion and high linearity. Sound will be Dynamic, detailed and neutral without being bright or harsh.
Zero Distortion Diamond ANALOGUE output stages
The D-28 has 4 groups of Zero distortion diamond rhombus output stage for the balanced output. Every part has been tactfully designed in such a way it can achieve zero distortion state without any adjustment. The output stages have built in 4 pairs of 15W transistor power to offer strong load capability.
It has a huge pure class A output power (1500mW at 100 ohm, max 9500mW at 25 ohm), it can drive most difficult headphones without exceeding the pure class A area.
The balanced drive mode kills the noise and distortion, which improves sound stage, reduces background noise and improves transparency.
The D28 have first-class headphone- and pre-amplifier performance
Linear Power Supplies
The D-28 uses a R-core transformer and in total 10 groups regulated power supplies distributed to digital and analog circuits separately.
There are 7 groups regulated PSU combined into double stage PSUs, to the digital elements.
The ES9038Pro D/A chip are very sensitivity to the power noise and ripple, therefore the D-28 has two groups transistor serve PSU to power the Left and Right channel and D/A parts separately. Compared to the ultra PSU chips, the serve PSU has more than 15dB on THD and dynamics, this boost the ES9038Pro to work at its best! The Left and Right D/A parts of the power supply are fully separated and will avoid channel crossover, which makes the soundstage deeper and wider.
The D-28 analog power supply for the analog sections have 2 high speed linear discrete transistors PSUs to provide an analogue sound.
HIGH PRECISION VOLUME CONTROL
Volume control consist of relay-controlled attenuators. Fully-independent, fully-balanced stereo volume controls. The volume controls feature consist of high-precision 0.05% tolerance film resistors and golden contact relays. Buffered inputs and outputs.There 4 channels volume boards are built in the unit to achieve ultimate balanced volume control. They are controlled by a digital signal controlling the high quality relays switching the precision resistors in analog area.
Quality of volume control is very important in balanced applications . It have to effectuate the four channels to work as synchronous as possible to keep the balanced signal in perfect shape. In traditional volume controls the balanced output will introduce distortion which will negatively influence sound quality and performance and might even get worse than a single ended setup and waste the advantages of balanced designed solution.
Internal Shielding
The D-28 has built in shielded boards, to separate the transformer, power supply, digital parts and analog parts to avoid interference’s. Including the power input IEC socket is copper shielded.