VAN DEN HUL THE EMERALD PREAMPLIFIER

Balanced Preamplifier

The Emerald balanced preamplifier is the next logic step after the introduction of The Grail SB. 

Stereo line-level preamplifier, fully balanced amplifier design with special “accumulator simulation” power supply (ASPS) design. The transformer resides in an external housing.
The amplifier design allows so-called mixed mode operation (balanced-to-unbalanced and vice versa). So a combination like  “unbalanced in / balanced out” is also possible like balanced in / unbalanced out” or “unbalanced in / unbalanced out” resp. “balanced in / balanced out”.
Amplifier circuit design with no overall negative feedback and cascaded input stages plus MOSFET output stages. All functions are controlled by an infrared remote control milled from a solid aluminium block. Status indication (choosen input, level attenuation, balance control etc.)  by liquid crystal display (LCD) at the amplifier front.

We have used the same design ideas from our Grail SB, like the complete balanced DC coupled circuitry, HF PCB with 24 carat gold connections and 0.1% precise selected components. The very innovative electronic circuitry is able to handle a mix of balanced and unbalanced signals both on the input and output.

To adjust all essential replay values, a remote control is part of the design. The channel to be used, the replay levels and possible channel unbalance can be fine-tuned.

To avoid any spurious signals and magnetic induction, the amplifier housing is made of 6 & 10 mm thick steel.

Specifically, the very natural and specific spacious replay is a benchmark of The Emerald. The very high resolution in combination with the natural dynamics in replay is another remarkable property.
Mains voltage: optional 230V or 115V
Weight: 19kg (w/o ext. transformer housing)

Input connectors and input resistance:

– Remote controlled inputs: 2 balanced stereo inputs + 2 unbalanced stereo inputs

– Input resistance: 10KOhms resp. to ground

Output connectors  and output resistance

– output: 1 balanced stereo output + 1 unbalanced stereo output. both outputs (bal. + unbal.) are simultaneously available if input resistance of the following power     amplifiers are above 10KOhms in parallel circuit.
– output impedance (on all outputs): appr. 350 Ohms
– output voltage: >= 6Vss on balanced output.

Bandwidth and distortion

– appr. 5Hz … 20KHz +- 0.2dB
– distortion: less 0,01% (1KHz) at 1Vrms at balanced output.

Level adjustment

remote controlled 128-step level attenuator with special low-level signal relais (switched resistor array with constant input resistance)  with 0,75dB/step

max. attenuation: -95,25dB. The step level attenuator circuit also makes possible a channel balance adjustment and a signal muting function, also operated by the infrared remote control.