The Technical Stuff
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22
Output (Makeup Gain)
Finally, an output control is employed to make up for the gain reduction applied by the gain reduction
circuitry; on the 1176LN, this is the function of the Output knob. Makeup gain is generally set so that
the compressed signal is raised to the point at which it matches the level of the unprocessed input
signal (for example, if a signal is being reduced in level by approximately -6 dB, the output makeup
gain should be set to +6 dB).
As you are adjusting a limiter or compressor, a switchable meter such as the one provided by the
1176LN can be helpful in order to view the strength of the outgoing signal (displayed when the meter
is set to +4 or +8), or the difference in levels between the original input signal and the gain-reduced
output signal (displayed when the meter is set to GR). When in GR mode, the 1176LN meter will read
0 dB when there is no incoming signal or when no compression is being applied.
About “All-Button” Mode
One of the most unique features of the 1176LN is the ability to press all four Ratio buttons in
simultaneously to create extreme amounts of compression or limiting. In this “All-Button” mode
(sometimes also known as “British Mode” because of its extensive use on many seminal British
recordings of the 60’s and 70’s), distortion increases radically due to a lag time on the attack of initial
transients (a phenomenon which might be described as a "reverse look-ahead"). The ratio goes to
somewhere between 12:1 and 20:1, and the bias points change all over the circuit, thus changing the
attack and release times as well. The unique and constantly shifting compression curve that results
yields a trademark overdriven tone that can only be found in this family of limiter/compressors.
About “Class A”
Most electronic devices can be designed in such a way as to minimize a particularly unpleasant form
of distortion called
crossover distortion.
However,
the active components in “Class A” electronic
devices such as the 1176LN draw current and work throughout the full signal cycle, thus eliminating
crossover distortion altogether.
Making A Custom Insert Cable
In order to ensure unity gain, the input and output to a compressor are normally derived from a mixer
channel or bus insert send and return. However, most mixing consoles provide such inserts on
unbalanced TRS (Tip/Ring/Sleeve) connectors, with the tip carrying the send and the ring carrying the
return, with the sleeve serving as common ground. Most 1176LN users will opt to use the rear panel
XLR input and output connectors instead of the less commonly used terminal strip connectors.
(
see page 24
) Premade “insert” Y-cables that provide a single TRS plug on one end and two XLR
connectors on the other end are commercially available for this purpose. However, it can be
considerably more cost-effective to make your own custom insert cable—something that requires only
basic soldering skills and a few inexpensive parts.
