Tube Preamplifier/DI Box: The Presonus TubePre v2is a fully professional tube preamp, with a dual-servo (no capacitors) gain
stage that lets you boost the program signal to smoking hot levels without
significantly increasing the background noise. Discrete components and
high-voltage operation offer dynamic range and detail not often found in other
single-channel tube preamps in its class.
XMAX Preamps: The TubePre v2 is equipped with Presonus XMAX
microphone preamplifiers for use with all types of microphones. The net result
of the XMAX preamp design is high headroom, low noise, wide dynamic range,
extended frequency response, and most importantly, musicality and transparency,
with smooth highs, solid deep lows, and everything in between. XMAX
preamplifiers are built with three key elements.
- High Voltage: The XMAX preamplifier runs on power rails
of 30V. Most off-the-shelf, op-amp-based designs run on power rails of 10V
to 18V. Higher-voltage power rails deliver more headroom, deeper lows,
smoother highs, and a richer overall sound.
- Discrete Components: XMAX preamplifiers only use
genuine transistors, resistors, and capacitors. Other Op-amps add noise,
coloration, and harshness to a signal. This discrete design delivers
ultra-low noise and transparency.
- Class A: Class A circuits have no crossover distortion
and deliver purer, clearer, and more musical results than the Class AB
designs that are found in many preamps.
Vacuum-Tube Stage: The XMAX preamplifier is followed in the signal
path by a 12AX7 vacuum-tube stage for high headroom and big tone.
Inputs/Outputs: The TubePre v2 rear panel sports separate unbalanced
1/4" instrument and
balanced XLR mic inputs, as well as and unbalanced 1/4" and balanced XLR line outputs.
Thanks to its separate instrument and mic inputs, it also serves as a dynamite
direct box (DI) for guitars and basses.
- Mic Input: The balanced XLR input of the TubePre v2 can be used
to connect a wide variety of microphones; including dynamic, condensers,
and ribbons. The 1/4" TS connector in the input section of the TubePre
V2 is for use with a passive instrument (e.g., guitar or bass).
- Main Outputs: The TubePre v2 features both an unbalanced 1/4" TS
and a balanced XLR outputs.
Note: An active instrument has an internal preamp and should be plugged
into a line input rather than an instrument input. Plugging a line-level source
into the Instrument input on the TubePre v2 may result in a very loud and
distorted audio signal.
48V Phantom Power: The Presonus TubePre v2 provides 48V
phantom power for the microphone input. There is a button on the front-panel
(labeled "+48V) which activates and deactivates phantom power.
Drive Control: The Drive knob controls the signal level being routed
through the 12AX7 vacuum tube. The effect ranges from subtle to extreme,
depending on the
setting; the more signal being sent to the tube, the more distortion you will
hear. This is great for guitar, bass, and even vocals, if that is the effect you
want to achieve. Of course, in some applications, tube drive is not needed.
Adjusting the tube drive can create these desirable effects:
- Warming Up The Sound: This is achieved by adding in a small
amount of tube drive (30% or less). It is especially desirable for vocals
and electric bass. The resulting sound is richer and sweeter.
- Overdriven Tube Sound: This effect is achieved by adding in 30 to
100% tube drive. The more tube drive you add, the more overdriven the sound
will be. This sound is extremely useful for creating distorted guitar, and
it's great for an authentic "blues harp" harmonica sound.
Gain Control: The Gain
(input gain) knob controls the amount of boost applied to the pre-amplified
signal and provides the following gain structure.
- Microphone Input: 80
dB of variable gain (-15 dB to +65 dB)
- Instrument Input: 80
dB of variable gain (-30 dB to +50 dB)
Phase Reverse: Reverses the polarity of the
signal. Use Phase Reverse when recording with more than one open microphone to
combat phase cancellation between microphones.
Instrument Input: This button activates the
instrument preamp circuit, bypassing the microphone preamp. When this button is
engaged, the XLR input will not pass signal.
80Hz: The 80Hz button is a
low-end roll-off filter. When enabled, this button causes all frequencies below
80Hz to be attenuated (cut) by 12 dB. This can be handy in live and studio
applications. For example, the 80Hz filter can help to reduce the "boominess" or
"muddiness" of a vocal, improving the overall clarity.
VU Meter: The analog VU
meter displays the output level of your TubePre v2.
Clip LED: The Clip LED will
illuminate if your input signal exceeds +20 dBu. Clipping the input produces
very unpleasant distortion. If you want good sounding distortion, increase the
Drive control while lowering the Gain.
Rugged Portable Chassis: The TubePre v2 is housed in a rugged case and
is small enough to carry almost anywhere. It can also be screw-mounted to a
standard rack tray.