Instrument Input; Gain Control; Pad Switch; +48V Switches - Art TubeFire 8 User Manual

Instrument Input

The 1/4" TS jack on the front panel provides a high impedance unbalanced input, and when used,
automatically switches off the mic pre-amp. (The rear combo jack's 1/4" TRS balanced input is lower
impedance and is part of the mic pre-amp. The rear jack is not intended to be used with high impedance
microphones or instruments.) NOTE: The PAD switch is disabled and does NOT affect the gain when using the
Instrument input.

Gain Control

This control adjusts both the mic pre-amp gain as well as the instrument input gain. The gain markings apply
to the mic pre-amp without the Pad switch depressed. (The instrument input gain is lower than the markings.)
Please refer to the HARDWARE OPERATION section to learn how to optimize the gain control for low noise
operation.

Pad Switch

This switch reduces the mic pre-amp gain to prevent clipping when high-level microphone or line level signals
are applied to the rear panel XLR / 1/4" TRS combo jack input. This switch does NOT affect the instrument
input.

+48V Switches

These switches provide phantom power to each set of four XLR inputs. Use phantom power only when the
microphone you are using requires it. Doing so will extend the life of the TubeFire 8 as well as reduce the
possibility of a shock hazard.

Phase Switch

This switch selects the output phase of the channel. There is a 180 degree phase inversion through the
channel when the switch is lit.

Low Cut Switch

This switch inserts a 100Hz 6dB/Oct. Low-Cut filter into the signal path. The filter is designed to remove
rumble, pops, and wind noise, yet still sound natural.

LED Meter

The four segment LED meter indicates the signal level at the input of the A/D converter. In addition to
monitoring the A/D level, the CLIP LED monitors all of the gain stages within the preamp channel for clipping.

Output Control

The output control provides gain or attenuation to adjust to a variety of system operating levels. This control
sets the level sent to the A/D converter (as well as to the output jacks if selected by the output source
switches).

Output Source Switches

The Output Source switches select the signal sent to the output jacks and the Headphone output.
Depressing a switch selects a pair of preamp outputs as the source for the corresponding output jacks as well
as selecting the source for the headphone output mixer.
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