After the 20dB pad, the signal is amplified 20, 30, or 40dBm by the microphone preamp. This low noise preamp provides 20dB of gain and adds only a few dB of noise. When used with the 20dB pad for unity gain, the unit generates 116dB maximum signal to noise ratio. Therefore, with 20dB of headroom the AS8X4 provides 96dBm “working” signal to noise ratio.
Following the microphone preamp, the signal is distributed to 4 sections - Iso1/2 driver, Iso3/4 driver, headroom circuit, and cue buss circuit.
The Iso outputs are broken into 2 sections Iso 1/2 and Iso 3/4.
The signal passes through a receiving
After the
Following the mic preamp, the audio signal is also distributed to the headroom LED and cue circuits.
The headroom circuit displays the amount of headroom left before clipping. 0, 12 and 24dB headroom LEDs visually indicate headroom and show signal level problems quickly.
The cue circuit buffers (isolates) the signal. Each momentary switch on the front panel places the signal from that channel on the cue buss that is then sent to the monitor. There, it may be listened to on headphones and metered in dB by the VU meter.
Description of controls
AS8X4 unit front panel:
Each channel provides a phantom on/off switch, a pad switch and a monitor button. Engaging the phantom on/off places 48VDC on the + and – terminals of the Direct IN/OUT terminal strips, and lights the phantom LED indicator.
Engaging the PAD switch attenuates input signal 20dB allowing it to accept line level signals.
The monitor button is momentary style and when pressed, that channel’s audio will be sent to the headphone jack and VU meter on the monitor unit.