Owner manual

1. INTRODUCTION
Congratulations on purchasing the Ivory 5052 Stereo Valve Processor by TL Audio!
The 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 units offer comprehensive control facilities, whilst remaining
straightforward to operate, and represent excellent value for money.
The 5052 is a dual channel processor with mic, line and instrument inputs, and
features a compressor, four band equaliser and peak limiter on both channels. The
compressor, equaliser and limiter stages can be operated in ‘dual mono’ or ‘linked
stereo’ modes, making the 5052 equally powerful for both mono/stereo tracking and
final stereo mix processing. A pair of illuminated VU meters monitor the input level,
output level, compressor gain reduction and limiter gain reduction for both channels.
The optional DO-2 digital output card allows 24-bit analogue to digital conversion
via an RCA phono type SPDIF output, with selectable 44.1 or 48 kHz sample rates
and the option to clock the converter to an external word clock source.
The block diagram of the 5052 is shown in Figure 1. A solid state, electronically
balanced input amplifier is used to achieve state of the art performance with very low
noise, low distortion and wide bandwidth. An ECC83/12AX7A triode valve stage (run
from a stabilised 150v DC supply) is used as a second stage voltage amplifier, to
obtain the classic valve sound and gradual overdrive characteristics. The preamp
stage also features 48V phantom power, phase reverse, 30dB pad and a high pass
90Hz filter. A Drive LED gives a visual indication of the signal level through valve
stages (and thus the amount of ‘warming’ taking place) while a Peak LED warns that
clipping is about to occur, and this monitors the signal at key points in the audio
path.
The compressor section offers fully variable control of threshold, ratio,
attack/release and gain make-up, and both hard and soft knee options are
available. A ‘Hold’ facility reduces LF distortion, and a side chain insert point is
provided for frequency conscious compression. Like all other TL Audio
compressors, the gain control element of the 5052 compressor stage is based
around a special transconductance amplifier, which avoids the use of VCAs and helps