Sound Performance Lab 9844 manual Tech Talk, Advantages of the SPL dual-stagepreamplifier

Advantages of the SPL dual-stage preamplifier

The GoldMike's engine is the newly designed SPL dual-stage preamplifier. During the first stage of amplification the signal is amplified by a semi-conductor circuit while the second stage applies tube electronics. We achieve a high common-mode-rejec- tion by using laser trimmed components. Likewise, minimal noise and distortion figures distinguish our high-quality preamp. Analog Device's semi-conductor (SSM2017) is very unreceptive to HF and hum interference, and is perfectly integrated by the PCB layout; wide PCB conductors guarantee a stable power supply even when extreme level changes demand an immediate current supply. The star ground wiring scheme ensures a quiet electronic performance. The dimensions of the PCB conductors, and their respective layout (wide or narrow), were especially designed for the integration of tubes and ICs in the preamplification circuitry. The MIC GAIN potentiometer adjusts the semi-conductor stage, allowing amplification up to 2200 times the original signal. The following secondary tube stage adds a constant 6 dB of gain; therefore, the same amount of tube character is added regardless of amplification. The MIC GAIN should be adjusted for a "0" VU meter reading. At this level the best signal-to-noise performance is achieved and the tube will perform in its ideal sonic range. (Please note that the VU readings are not peak PPM but average levels. In other words, watch out for the meter hitting the red.)

In summary, our dual-stage design maximises the amplification power and signal-to-noise performance of the SPL semi- conductor at the first stage and then maximises the warmth and liveliness of a meticulously selected and tested ECC 83 tube at the second stage. This makes the GoldMike an ideal partner for high- end HD recording. The unit's dynamic range of 111 dBu even outperforms some 24-bit recording gear.

Tech Talk

The GoldMike combines superb signal-to-noise specs with not only the amplification power of semi- conductors but also the warmth and liveliness of tubes.

An outstanding dynamic range of 111 dBu outperforms even the average 24-bit recording system.

Advantages of the dual mono design

GoldMike's two mono amplifier blocks are designed with a central power supply that utilises a star ground wiring scheme. Chief advantages of this particular layout are the excellent channel separation and, respectively, the low crosstalk figures.

In your daily work you will find many practical applications for these advantages. You may use the GoldMike's channels for a snare and a vocal (arguably the most important elements in a mix) simultaneously. Stereo recordings, benefiting in particular from the low crosstalk figures, will have wider stereo depth and precise spatial definition. Another advantage of the central power supply with a star ground wiring scheme is that the two indivi- dual circuitries, operating discretely, can deliver identical sonic performances per channel. The current demands of one channel (i.e., snare) are not compromised by the current demands of the other channel (i.e., vocal). All power supplying conductors, layed out identically and symmetrically, provide both channels with the necessary current.

Dual-Mono-Layout,with central power supply and star grounding, delivers excellent channel separation

•two discrete signals (snare,vocal) may be recorded simultaneously without crosstalk

•precise spatial definition

•identical sonic performance per channel

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