TL Audio 5051 - Manual (Page 11)

3.12 Rear
Panel.
The rear panel connectors are identified in Fig.3. Make sure that all settings,
mains and audio connections have been made as described above before
attempting to operate the equipment.
4. OPERATION
4.1 Input Stage.
The input gain control sets the level of the mic, line and instrument signals into
the 5051. The signal source is selected by the 4-position switch above the
input gain knob. Input choices are ‘Mic 48V’ (for condenser microphones that
require phantom power), ‘Mic’ (for dynamic or most ribbon microphones),
‘Line’ and ‘Instrument’. The Instrument input allows high impedance
instruments such as guitars or a bass etc to connect directly into the 5051 and
eliminates the need for a DI (Direct Injection) Box. A wide range of signals can
be fed into the 5051, and the input gain control also allows the valve stages to
be driven to a variable degree. After the preamp stage the signal passes
through a triode valve stage positioned between the input circuit and the
compression stage. Increasing the input gain pushes more signal level into the
valve, thus generating more harmonic distortion and creating that special
“valve sound”. At the same time the output level can be turned down to
preserve the same level at the 5051 output, so a choice of sounds is available.
For a more pronounced valve sound, turn up the input gain and reduce the
output gain, and vice versa for a cleaner sound. Don’t be afraid to push the
5051 hard!
As well as driving the valves harder, increasing the input gain control setting
will also have a pronounced effect on the amount of compression, as the
threshold will remain constant as the input level increases. If the input gain is
adjusted the threshold can be re-adjusted accordingly to maintain a similar
amount of compression.
4.18 Microphone
Input.
When using the 5051 with a microphone source, care should be taken not to
apply too much gain at the input. Start with the input gain control set to
minimum, and the output master at the mid-point (12 o’clock position). The
input gain can then be gradually increased until the VU meter registers about
0VU on normal signal level, when set to read ‘I/P’. The master output level
should then be adjusted to produce the required output.
CAUTION: Never switch phantom power on or off, or plug/unplug a
microphone with phantom
power applied unless the output level control