Hardware manual

Apollo FireWire Hardware Manual Front Panel

(17) Monitor Output Level Meters

The 10-segment LED meters display the signal peak output levels for monitor outputs 1 & 2 (Left & Right) at

the output of the D/A converters. These meters are before the Monitor Level control (pre-fader) and reflect the

D/A converter levels regardless of the current Monitor Level and Headphone Level knob settings.

The dB values of the monitor meter LEDs are indicated between the left and right channel meters. When digital

clipping occurs, the red “CLIP” LED illuminates. Avoid clipping at the monitor D/A converters by reducing the

monitor bus output level and/or the channels feeding the monitor output bus.

(18) Monitor Level and Mute Knob

This rotary encoder serves two functions. Rotating the knob adjusts the monitor output level, and pushing the

knob mutes the monitor outputs.

Monitor Level

Rotating the knob clockwise increases the signal level at monitor outputs 1 & 2 on the rear panel. Although this

is a digital control, the monitor volume is attenuated in the analog domain, after D/A conversion (digitally-

controlled analog volume). This method provides the utmost monitoring fidelity, in contrast to digital volume

controls that reduce levels by truncating the word length (“dropping bits”).

Monitor Mute

Pushing the Monitor knob toggles the mute state of the signals at monitor outputs 1 & 2 on the rear panel.

When the monitor outs are muted, the Monitor Level Indicator (#19) is red.

Note: Monitor Mute does not mute the headphone outputs.

(19) Monitor Level Indicator

The signal level at the rear panel monitor outputs is displayed with this ring of illuminated indicator LEDs

surrounding the Monitor Level knob. The LEDs are green when the monitor outputs are active, and red when the

monitor outputs are muted. This meter is after the Monitor Level control (“post fader”). It indicates relative

levels only and is not calibrated to specific dB values.

(20) Headphone Level Knobs 1 & 2

These analog knobs control the volume of Headphone Outputs 1 & 2 on the front panel. Each headphone output

has its own volume control. Headphone levels are attenuated in the analog domain (after D/A conversion) for

maximum fidelity.

(21) Headphone Outputs 1 & 2

These ¼” stereo TRS phone jacks are for connecting stereo headphones to Apollo. Headphone outputs 1 & 2 are

individually addressable by the device drivers and the Console application. Unique mixes can be created for

each headphone output, or they can be switched to mirror the monitor outputs in the Console application. When

mirroring the monitor outputs, the headphone outputs are unaffected by Monitor Mute (#18), to facilitate

recording/tracking with headphones while the monitor speakers are muted.

(22) Power Switch

This switch applies power to Apollo. When the unit is powered on, the Universal Audio logo is illuminated. The

external power supply must be properly connected for this switch to function.