TL Audio VP-1 - Manual (Page 2)

1 INTRODUCTION
Congratulations on purchasing the VP-1 Mono Valve Processor from TL Audio.
The VP-1 combines classic Pentode and Triode valve techniques with Class A
discrete and solid state circuitry to produce a unit providing comprehensive facilities
for all aspects of single channel microphone and instrument pre-amplification and
processing.
The VP-1 features include:
- Class A discrete and Valve pre-amplification,
- Variable High Pass Filter,
- Expander / Gate,
- Vocal De-Esser,
- Fully variable Compressor with Transconductance and Optical modes,
- 4 band Parametric Equaliser,
- Variable Threshold Optical Limiter,
- Optional digital output, selectable up to 24bit, 96Khz.
The block diagram of the VP-1 is shown in fig.1. There are four input sources:
microphone XLR, balanced line +4dBu XLR, unbalanced line -10dBu jack and front
panel instrument jack socket.
The mic input features switchable 48V phantom power and 30dB pad, and is
transformer coupled to both an all-valve pre-amp (consisting of pentode and triode
stages) and a class A discrete pre-amp, providing two of the options on the input
selector switch. The two line inputs are summed together for the third input selection,
with the instrument input available as the fourth selection. The instrument input is
front panel mounted for easy access, and is suitable for a variety of sources, including
guitar, acoustic pickup and keyboard. The input stage sensitivity for the mic and
instrument inputs is switchable in 10dB steps, followed by a +/-15dB trim control
effective on all inputs.
The input section also provides a continuously variable high pass filter to eliminate
unwanted LF noise from the input source, and a phase reverse switch. An insertion
point is provided immediately after the input section. The insertion point is
unbalanced, at a nominal operating level of -2dBu.