Aphex 188 Eight Channel Mic Preamp - Manual (Page 17)

much easier and quicker than the alternative of swapping cables and equipment.
Low Cut 75Hz
To help reduce low frequency rumble that can be caused by wind, handling of the microphone or bad vocal
articulation (popping “P’s”), a 75 Hz, 12dB per octave low cut filter is provided. In general, this filter could
be engaged when mic’ing vocals as it will not usually affect the tonality of the human voice. When mic’ing
instruments with very wide bandwidth in the low frequency range, you may want to defeat the filter unless there
is substantial extraneous low frequency noise.
26dB PAD
Using the 26dB PAD attenuates the preamp’s input signal by 26dB. It allows the channel to receive line level
inputs from a wireless microphone receiver or other high level device.
PHANTOM +48V
Activating the PHANTOM +48V function engages the internal phantom power source. The 48 volt microphone
power ramps up and down very slowly to avoid glitches. The ramping also protects powered microphones from
current surges, which have been known to cause microphone damage.
CAUTION: Hot-plugging a microphone into a phantom powered input causes a very loud impulse which can
cause speaker damage. To be safe, allow at least 20 seconds for the phantom power to discharge before plugging
or unplugging a microphone.
SYSTEM CONFIGURATION
CLOCK SOURCE
This selects wheher the internal clock or an external clock is selected as the clock source for the digital auido
output. Either word clock or a standard AES signal can be used as an external source.
SAMPLE RATE and FORMAT
If Internal is selected, sample rate and format can be selected by rotating the encoder to the desired sample rate
and format (44.1kHZ, 48kHz, 44.1kHz SMUX, 48kHz SMUX, 88.1kHz SMUX, 96kHz SMUX) and pressing
in the encoder. If External is selected the display will show the frequency that is closest to the rate at the input
to the External BNC. If over 48kHz, the format will automatically be SMUX. If under 48kHz the format must
be selected as normal ADAT or SMUX by rotating the encoder to the desired format and pressing the encoder
to select. Note: When 44.1 or 48kHz is selected with SMUX format, the effective sampling rate will be double
(88.2 or 96kHz).
188
Page 17 Aphex Model 188