Audio-GD Master 19
Préamplificateur Symétrique Amplificateur Casque Class A ACSS 9W 40Ω
Audio-GD is back with its Master 19, a preamplifier and headphone amplifier featuring a symmetrical Class A architecture with totally discreet analog stages and ACSS circuits. It will easily integrate into any high-fidelity audio system, offering high sound quality, transparency and precision.
Class A output stages
The Master 19 has 4 output stages, each element is paired before assembly so that no adjustment is required. These output stages integrate 4 pairs of 150W transistors operating in Class A. Thus, the balanced output has 4 times more power than an unbalanced output.
The Class A structure offers a high quality reproduction and allows, by the design of the Master 19, to offer an important energy reserve at the headphone output. The balanced outputs cancel out noise and distortion for an incredibly rich and clear sound.
The Master 19 offers both balanced XLR and unbalanced RCA connectivity, but also ACSS input and output. On the headphone outputs side, the device features an asymmetrical 6.35mm jack and a 4-pole balanced XLR on the front panel. All outputs of the Master 19 can be used at the same time.
The input channels of the Master 19 are individually shielded and those not in use are completely disconnected so that the audio signals are not affected by the connected equipment.
The power supply stage of the Master 19 uses two transformers and 4 PSUs in pure Class A to independently power the audio, control and display circuits. These PSUs Class A connected in parallel have a very high impedance to prevent the pulses from affecting the preamplifier and output stages.
Unlike conventional volume controls using simple potentiometers, the Master 19 consists of a 4-channel relay attenuator using high-precision film resistors and relays with gold plated contacts. This system uses an I/V conversion in which the output corresponds to the current and not the voltage. This operation maintains a flat frequency response and never alters sound quality at any volume level.
The quality of the volume control is all the more important in a symmetrical architecture like that of the Master 19 in order not to create distortion. The volume control of the Master 19 is done on 100 steps with an attenuation range of 90dB. It has an exponential curve and allows precise adjustment of the volume level.
The many DACs available on the market have different architectures and therefore a variable output impedance depending on the model. To avoid possible effects on sound quality due to different output impedances of the DACs, the Master 19 has 4 FET Class A input buffers on board. All input signals pass through these FET buffers, lowering the impedance to a very low level, regardless of the source's output impedance.
Metal remote control
The Master 19 is also delivered with a robust and stylish Aluminium remote control. This allows simple and remote access to basic functions such as volume control or source selection.
|Inputs||2x Single-ended RCA|
2x Balanced XLR
|Outputs||1x Single-ended RCA|
1x Balanced XLR
1x Single-ended Jack 6.35mm headphone output
1x Balanced XLR 4 poles headphone output
|Adjustable gain||Low : +16dB (XLR)|
High : +25dB (XLR)
|Headphone output power (balanced, Class A)||9000mW @ 40Ω|
3800mW @ 100Ω
1250mW @ 300Ω
175mW @ 600Ω
|Headphone output power (single-ended, Class A)||2500mW @ 40Ω|
1050mW @ 100Ω
350mW @ 300Ω
175mW @ 600Ω
|Preamplifier output level||RCA : 10V|
XLR : 20V
ACSS : 2.4+2.4MA
|Input impedance||XLR : 90kΩ|
ACSS : < 10Ω
|Frequency response (XLR input)||20Hz - 20kHz (+/-0dB)|
1Hz - 220kHz (+0dB, -3dB)
|Supply voltage||220-240V AC 50/60Hz|
|Dimensions||360 x 360 x 85mm|
|Package||1x Audio-GD Master 19|
1x Metal remote control
1x Power cable