Owner's manual

1. INTRODUCTION
Congratulations on purchasing the Ivory 5013 Dual Valve Equaliser by TL
Audio! The T L Audio Ivory 2 Series consists of a range of hybrid valve signal
processors, which utilise low noise solid state electronics in conjunction with
classic valve circuitry to produce audio processing units offering very high
quality signal paths with the unique valve audio character. The Ivory 2 Series
units offer comprehensive control facilities, whilst remaining straightforward to
operate, and represent excellent value for money.
The 5013 is a stereo parametric valve equaliser featuring four fully variable EQ
bands on each channel. The block diagram of one of the channels is shown in
Fig.1. The balanced line input is via an XLR socket, whilst the unbalanced
connection is via a 0.25” jack socket. The nominal input levels are +4dBu on
the balanced connections and -10dBu on the unbalanced connections, but
these may be shifted to +18dBu and +4dBu respectively by the rear panel
input level switch. This feature offers greater flexibility of connection to other
equipment, particularly the latest generation of digital recorders which operate
at very high signal levels. The line inputs have an overall gain range of -20 to
+20dBu.
The front panel instrument jack sockets allow direct access to the channel
inputs. The instrument inputs eliminate the need to use external DI (Direct
Injection) boxes as they are suitable for a variety of sources, including electric
guitars, bass guitars, acoustic pickups, synths, samplers and drum machines.
The instrument input level is controlled by the 5013 input gain control. The
input level is monitored by both “Drive” and “Peak” LEDs: Drive is a variable
intensity LED designed to indicate the signal level through the valve stages,
and thus the amount of “warming” applied to the signal. Peak is a conventional
warning that clipping is about to occur, and will illuminate if there is an
excessively high level present not just at the input but at any point in the signal
chain.
Both channels feature a four band parametric equaliser, with each band
providing variable frequency, gain and Q (bandwidth) controls. The LF and HF
sections include options for shelving or peaking response by means of a pull-
out Q control. Pulling the Q control knob ‘out’ converts the section to a
shelving type equaliser, with the Q control then becoming inactive. The ‘FAT’
contour switch provides a subtle but effective LF and HF lift while at the same
time reducing the gain in the mid range - this filtering provides a perceptible
increase in warmth without altering the overall signal volume.
The master output level controls are post-EQ. These controls are centre-
detented for ease of line-up, but may be varied in conjunction with the input
gain controls to alter the operating level through the circuitry, optimising the
operating level and hence headroom and signal to noise ratio of the unit. It is
possible to push the input levels harder to drive the valve stages and