- Fully balanced class A design built by discrete analog stages without any opamps or coupling caps in the signal channels.
- Non- feedback ACSS analog output stage.
- Uses high grade parts and exactly matched transistors.
- Four-channel 100 steps digitally controlled relay-based volume control avoids channel imbalance and improves sound quality .
- Drives headphone output to 8000 mW at 40 ohm output
The pure analog technical design is difficult (impossible?) to upgrade. The 2019 Edition has got new firmware to offer additional functions and easy control of the functions. Sound quality is same with previous generation (Great!)
|Frequency Response||20Hz – 20kHz (-0.1dB) / 3Hz – 135kHz (-3dB)|
|Headphone Output Power (Class A)||(300mW) / 600 Ohm (150mW) / 300 Ohm (300mW) / 600 Ohm|
|Headphone output power (Max)||(300mW) / 600 Ohm (600mW) / 300 Ohm (300mW) / 600 Ohm (900mW)|
|Preamp output power||10V (RCA) / 2.4mA (ACSS)|
|Output impedance||1 Ohm|
|Input impedance||47K Ohm (RCA) / 94k Ohm (XLR) / 10 Ohm (ACSS)|
|Dimensions||240 x 360 x 80mm|
DISCRETE ANALOGUE OUTPUT STAGES
The analog output stages are as important, they have a tremendous influence on the final sound quality. After d/a conversion by the R2R D/A modules the analogue signal is transported by fully discrete matched-transistor output stages; DC-coupled design with first class through-hole components. No SMD components are applied in the analogue section. The high speed unique ACSS ((Audio-gd Current Signal System) output stages are non-feedback and current driven. Unique performance because almost all other designs need to convert the signal multiple times from and to current and/or voltage, resulting in less detailed and less transparent sound-stage The output buffers are single ended FET; two stages in parallel to reach very low output impedance. All output stages are in pure class A without (negative) feedback to achieve purest and a real live sound reproduction. The 4 OPA op-amp’s are DC servos, this way no coupling-capacitors are needed and DC output is automatically biased. The listener will be presented a strikingly transparent and neutral sound.
ACSS – Current Amplification
Audio-GD has developed an advanced current-driven amplifier technique. Also known as ACSS, Audio-GD Current System Signal. This special technique ensures that the signal travels a much shorter path and that ensures a more transparent, faster and more neutral reproduction. A similar technique is used by, for example, KRELL. The Current Conveyor technology mostly components are the current mirror. The Current Conveyor technology isn’t a new technology, at 1966 , professor K.C. Smith and A.S.Sedra publish the concept “current mode analogue circuits “ .
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.
The DAC consist of A tuned low noise, low flux leakage, R-cores transformer. In total 65W power to supply all digital parts and the left and right analog boards. The DC power is distributed separated power regulators. All are pure class A low noise shunts; fed by linear power supplies. Resulting in ultra-high speed and clean power for all individual parts.