User Manual

SM Pro Audio Page 7 of 12 Tubebox Manual
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7 Output level
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The output level (labelled 0 to 10) is a rotary control that simply controls
the output level of the TUBE BOX.
7.1 Phase reversal switch
A phase reverse switch is available for reversing the phase of the signal
by 180 degrees. This can be desired in situations such as recording a
snare drum from above and below the drum simultaneously. By reversing
the phase on one of your microphone signals you will achieve a better
result, recording full range of signal without a phase cancellation
occurring. It is also used for matching the rest of your gear or recordings
or removing feedback when recording stereo pairs.
7.2 80Hz low-cut
(high-pass) filter switch
The low-cut (high-pass) filter switch enables and disables the 80Hz high-
pass filter. Engaging this filter effectively removes low frequency “rumble”
and other unwanted noise by attenuating the signal dB below 80Hz.
8 Making sound
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Make your physical connections ...
Simply make your signal connections by either connecting an instrument (guitar, bass,mic etc) to the
instrument input on the front panel, or connecting an input to the rear of a 500 series power supply
box.
Do you need phantom power? ... or to change the phase of your input signal?
If you are using a condenser microphone that requires phantom power, select the phantom power
switch to the on position. You can also choose to switch the polarity of your signal at this stage if
required.
Set your input gain control ...
Set your input level. Adjust the input rotary control to an acceptable level. This is a good time to
check the clip indicator to ensure you are not overdriving the tube pre-amp with too much signal. If
your signal is too strong, reduce the amount with the rotary control. If you cannot reduce the signal
enough to stop the clip indicator constantly illuminating, you can enable the -20dB PAD to assist in
reducing the incoming signal gain.
Do you desire compression? ...
You can now choose to add some optical compression to your signal if desired. To initiate, press the
compressor on/off switch to the on position. Set your attack and release pots to the desired settings,
and adjust the compression ratio rotary control until you are satisfied with the result.
Set your output level ...
Adjust your master output level rotary control to the required amount.
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