TL Audio VP-1 - Manual (Page 18)

4.35 Output
Level.
This control acts much like the fader on a recording console, in that it regulates the
overall level produced at the VP-1’s line outputs. This makes it ideal when recording
direct to tape or hard disc, since it enables the level to tape to be precisely controlled.
The range of the control is from -
∞ (i.e. complete attenuation) through to +15dB. This
extra output gain is perfect for digital recording since many digital recorders require
large input levels to fully modulate them - it’s not uncommon to have to input +18dB
to generate a 0VU reading on a digital recorder.
As detailed in the above section, the output limiter acts after the output level control,
so if the limiter is engaged then its threshold setting will have ultimate control over
final output level.
4.36 VU
Meter.
The VP-1 is equipped with an illuminated VU meter, which via the four way meter
selector switch can be used to monitor input level, output level or compressor gain
reduction.
In output mode (“O/P”), the meter is calibrated for nominal level of +4dBu at the
balanced output = 0VU. Similarly, 0dB on the meter also corresponds to -10dBu at
the unbalanced output. However, should a very high output signal be required, for
example +18dBu for a digital tape machine, the meter will be fully modulated and
indicate full scale. This situation is catered for by the “O/P +10” position on the meter
selection switch, which attenuates the signal by 10dB before displaying it on the
meter. Thus 10dB should be added to the meter reading in this mode, i.e. a meter
reading of 0VU is equivalent to the normal level of +4dBu, plus 10dB, giving a signal
level of +14dBu.
In “I/P” mode the meter may be also be switched to indicate the input signal level
(post the pre-amplifier but pre the EQ and compressor), or the amount of gain
reduction (compression) applied by the compressor section (“G/R”). In G/R mode, if
the signal is below the threshold, the meter will read 0dB: i.e. no gain reduction is
occurring. As the signal passes through the threshold the meter will show a negative
value, indicating that gain reduction has started at the compressor stage. Note that the
gain reduction indicated is a measure of the degree of compression, and does not
include any gain make-up applied - nor does it indicate any limiter gain reduction that
may be occurring further down the signal chain.
4.37 Digital Output Option.
The VP-1 supports an optional digital output card (DO-1) which is fitted via the rear
panel. The DO-1 card provides AES/EBU, SPDIF and TOSLINK optical outputs,
plus a Wordclock input. The master section of the VP-1 provides front panel control
of the bit rate and sample rate, plus an LED indication of external lock and a bargraph