PreSonus FireStudio Tube - Manual (Page 30)

CONTROLS AND CONNECTIONS
27 | PreSonus 2008
3.2 FRONT PANEL LAYOUT
 SuperChannels. Your FireStudio Tube is equipped with two “SuperChannels.” These channels are Class
A vacuum-tube microphone and instrument preamplifiers with full-featured analog limiters. Each
channel has its own controls.
o
Combo Connectors. Each SuperChannel has a Combo mic/instrument connector. This
connector lets you use either ¼” Female TS or XLR connectors in the same jack. Channels 15
and 16 of FireStudio Tube are ¼” instrument and microphone XLR inputs.
o
48 Volt Phantom Power. Each SuperChannel has 48V phantom power available individually
via button switches on the front panel.
 XLR-connector wiring for phantom power:
 Pin 1 = Ground
 Pin 2 = +48V
 Pin 3 = +48V
o
Input Gain/Trim Control. This knob provides the following gain structure:
 40 dB of variable gain (-10 dB to +30 dB)
o
Drive. This knob controls the amount of signal routed to the 12AX7 vacuum tube, which lets
you control the amount of tube saturation. Greater levels of tube saturation give the signal
greater warmth and a richer sound. This works equally well on microphones and instruments.
o
Limiter. This knob sets the threshold of the analog limiter from -18 dBfs to 0 dBfs (-8 dBu to
+10 dBu). The threshold is the point at which the limiter will engage. Once this threshold is
reached, no more of the input signal will be allowed to pass through. Turning the knob
clockwise raises the threshold, allowing more of the input signal through. Turning the knob
counter-clockwise lowers the threshold, allowing less of the input signal through.
o
Gain Makeup. This knob adjusts the gain after the limiter threshold. This is used to compensate
for gain reduction, raising the gain of the output signal without raising the limiter threshold.
This is especially useful when using the limiter as an effect to overcompress the signal. By using
the Gain Makeup knob, you can set the threshold extremely low and still record a strong signal.
 Instrument Inputs (Channels 15 and 16). The ¼” TS connector on Channels 15 and 16 are for use with
an instrument (guitar, bass, etc.). When an instrument is plugged into the ¼” input, a high impedance
input buffer is switched into the preamp circuit and the FireStudio becomes an active instrument
preamplifier.