T L Audio EQ-3012 User Manual

T L Audio

CRIMSON SERIES

User Manual

EQ-3012 PARAMETRIC EQUALISER

Tony Larking Professional Sales Limited,

Letchworth, England.

Tel: [phone]. International [phone].

Fax: [phone]. International [phone].

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.

PRECAUTIONS

The T L Audio EQ-3012 Parametric Equaliser requires very little installation, but like
all electrical equipment, care must be taken to ensure reliable, safe operation. The
following points should always be observed:

- All mains wiring should be installed and checked by a qualified
electrician,

- Ensure the correct operating voltage is selected on the rear panel
before connecting to the mains supply,

- Never operate the unit with any cover removed,

- Do not expose to rain or moisture, as this may present an electric
shock hazard,

- Replace the fuse with the correct type and rating only.

Warning: This equipment must be earthed.

INSTALLATION

AC Mains Supply.

The unit is fitted with an internationally approved 3 pin IEC connector. A mating
socket with power cord is provided with the unit, wired as follows:

Brown: Live.

Blue: Neutral.

Green/Yellow: Earth (Ground).

All mains wiring should be performed by a qualified electrician with all power
switched off, and the earth connection must be used.

Before connecting the unit to the supply, check that the voltage selector switch on the
rear panel is correctly set. The unit may be set for 115V (accepting voltages in the
range 110V to 120V, 60Hz AC), or to 230V (for voltages in the range 220V to 240V,
50Hz AC). Adjustment to the operating voltage should be made by sliding the selector
switch left or right with a small screwdriver until the desired voltage is displayed. The
mains fuse required is 20mm anti-surge, 1AT rated at 250V. If it ever necessary to
replace the fuse, only the same type and rating must be used. The power consumption
of the equipment is 30VA.

Warning: attempted operation on the wrong voltage setting, or with an
incorrect fuse, will invalidate the warranty.

Audio Operating Level.

The equaliser is equipped with inputs and outputs suitable for connection to a wide
variety of other audio equipment. Generally, the balanced XLR connections will be
required for interfacing to other professional equipment, where the operating level
(line-up level or nominal level) will be +4dBu, or about 1.2V rms. The unbalanced
jack connectors are generally intended for interfacing to semi-professional equipment
and have an operating level of -10dBu, or about 225mV rms.

The equaliser may be used to change between operating levels, for example by
connecting the unbalanced output of a semi-pro mixing console to the equaliser’s
unbalanced input, and taking the balanced output of the equaliser to the balanced input
of a tape machine at +4dBu. All inputs and outputs of the equaliser may be used
simultaneously if required. Balanced interconnection is always preferable to obtain the
best headroom and noise rejection, but can only be used if the other equipment in the
chain, e.g. the mixing console, also has provision for balanced connections.
Audio Inputs.