T L Audio EQ-3012 User Manual - page 2
INTRODUCTION
The T L Audio Crimson Series utilises low noise solid state circuitry to produce audio
processing units offering very high quality signal paths with comprehensive control
facilities. The Crimson Series are straight-forward to operate, and offer excellent value
for money.
The EQ-3012 is a four band, fully parametric equaliser. The four bands may be
configured as two bands on each of the equaliser’s two channels, or cascaded to form
a single channel, four band equaliser. Bands 1 and 2 are normally configured in
channel A, and bands 3 and 4 in channel B, but frequency range multiplier switches on
bands 2 and 3 provide a flexible four band mode with detailed coverage of the entire
audio bandwidth.
The block diagram of the equaliser is shown in fig.1. It has three input sources - a
balanced line level input via an XLR connector, an unbalanced line level input via a
jack socket, and an instrument input also on an unbalanced jack socket but located on
the front panel where it provides a convenient means of patching a guitar or keyboard
directly into the equaliser. All three inputs may be used simultaneously. The gain of
the input stages is controlled by a centre-detented control, calibrated for 0dB nominal
gain from the line input sources at the centre and providing +/-20dB of variation. The
instrument input has a sensitivity switch associated with it, to match the gain to a low
level pickup (e.g. a passive guitar or microphone) or a higher output source such as a
keyboard or active guitar, followed by the 40dB variation of the input gain control
Following the channel A input stages are two parametric equaliser stages. Band 1
offers fully variable cut/boost, centre frequency and Q (bandwidth) control. Band 2 is
similar, but also includes a divide by 10 frequency range switch.
A variable intensity peak LED monitors the output of the equaliser stages, providing
an indication of the amount of drive and headroom available. The signal chain is
completed by an EQ-in switch plus balanced and unbalanced output driver stages.
Channel B is also configured with two bands of fully parametric equalisation - band 3
including a frequency range multiplier switch. In 4 band mono mode, the input stages
of channel B are replaced with the output of channel A’s equalisation, cascading all
four bands onto the same audio path. In this mode, the signal input is via channel A
and the output is via channel B. The output from channel A remains operative, but
with just the first two bands of equalisation effective.
Please read this manual fully before installing or operating the Equaliser.