TL Audio 5051 - Manual (Page 14)

to music, as well as fattening up sounds and creating a more professional
sounding recording. With the 5051, you have the added benefit of valve stages
in the signal path, which create a warmth and presence just not obtainable
with solid state or digital products.
4.9
Why Valve Compression?
Valve compression yields a particularly special sound which has become very
sought after, particularly with the widespread use of digital products. The
reason valve equipment sounds special is due to two things: harmonic
distortion and natural compression. When the signal through a valve is
increased, it tends to generate a particular type of subtle and desirable
distortion, called “second harmonic” distortion. This has the effect of thickening
and warming the sound, and the more the level you feed to the valve stages,
the more of this harmonic distortion will be produced. You should be able to
hear this effect as you increase the Input Gain on the 5051.
Secondly, valves will tend to naturally compress an audio signal, again
particularly as the signal level is increased. This itself also contributes to the
warmth produced by the 5051.
4.10 Overview of Compressor Operation.
To operate the 5051 successfully an understanding of each control will help to
obtain the best results. If you are unfamiliar with the effect of compression it
may help to adjust the controls to extreme settings and listen to the sonic
effect. Generally compressors are used in two different ways: either to
enhance the signal and control the dynamic range as unobtrusively as
possible, or used more severely to specifically to create an effect.
4.11 Threshold.
The Threshold is the point measured in decibels that any compression comes
into operation. The Threshold control is variable from +20dB in the most
anticlockwise position to -20dB at the most clockwise position. Any signal
below the Threshold passes through the unit unaffected; while signals above
the Threshold are reduced in gain (and are thus ‘compressed’). This does
depend on the Soft or Hard knee to some extent as the Soft knee is more
gradual around the Threshold point.
Unlike some compressors, the Threshold control on TLA units including the
5051 starts at a ‘plus’ value in the counter-clockwise position, and decreases
to a ‘minus’ value as you rotate the control clockwise. The reason for this is as
you turn the Threshold control on the 5051 clockwise (i.e. towards the
negative region) then the degree of compression will increase. We think this is
logical, whereas the common method of turning the control ‘down’ to achieve
more compression is not - but beware, some other compressors may work in
the opposite direction!