ART Pro Audio TubeFire 8 - Eight Ch. Mic Pre with Firewire - Manual (Page 9)

REAR PANEL
Balanced Input Jacks – XLR & 1/4” TRS Combo Jacks
These balanced inputs are used for both microphone and line level signals. The gain sensitivity is identical for
both the XLR and 1/4” TRS jacks, however the XLR input impedance is 6.4K Ohms and the 1/4” TRS input
impedance is 20K Ohms. The front panel Pad switch varies the sensitivity of both inputs.
Balanced Output Jacks
Each channel has a low impedance 1/4” TRS balanced jack.
Output Level Switch
This switch optimizes the output level of the rear output jacks with your system operating level. Depress the
switch when connected to +4dB systems. In this case the maximum output is +22dBV when the digital level
equals 0 VU.
When the switch is in the “out” position, the output levels are optimized for –10dBV systems.
One way to determine how this switch should be set is to send audio through the TubeFire 8™ from a
computer and run it into a line input on a mixer or signal processor. Check the meters on the mixer or signal
processor to see if the level appears to be too high (clipping) or too low (barely showing any indication on the
meters). Set the Output Level switch so that the level meters in the external gear do not indicate excessive
clipping yet still provide good full-scale (or near full scale) deflection.
FIGURE 3 - Rear Panel
Wordclock Input and Thru Jacks
The Wordclock input is used to externally sync the TubeFire 8™ to a master clock source. The BNC
Wordclock Input jack is connected directly to the BNC Wordclock Thru jack, providing the ability to loop
through the TubeFire 8™ and connect other devices to the wordclock sync source, saving the use of a BNC T–
adapter.
The input is high impedance thus leaving the wordclock connection unterminated. (A 75 Ohm BNC
terminator should be used on the Wordclock Thru jack if the Wordclock Input jack is used only by itself.)
Firewire Jacks
The Firewire jacks are interchangable and allow both connection to your computer and to other Firewire
devices including additional TubeFire 8™ units.
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