User Manual
Apollo Twin MkII Hardware Manual Controls & Connectors 23
Preamp Options 
The Option Buttons control the PREAMP options (a – f below) for an input channel when 
that channel is selected (3) with the PREAMP button (7). A preamp option is active 
when its indicator in the upper row of the Options Display (12) is lit, and inactive when 
the indicator is dim. If the indicator is unlit, the option is unavailable.
Note: In MONITOR Mode, the preamp options cannot be modified and the upper 
row of the Options Display is unlit.
Preamp options
(a) INPUT Select
Selects the active input jack for the channel. Press to alternate between the mic and line 
inputs. The current selection is displayed by the input type indicators (5).
The Hi-Z input is selected automatically whenever a ¼” mono (tip-sleeve) plug is 
connected to the front panel’s Hi-Z Instrument jack (14).
Note: Hi-Z input is available for channel 1 only.
(b) FILTER
Enables a low cut (high pass) rumble filter with a cutoff frequency of 75 Hz.
(c) +48V
Enables +48-volt phantom power for the mic input. Phantom power is typically needed 
for condenser microphones. +48V is available for the microphone inputs only.
Caution: To avoid potential equipment damage, disable +48V phantom power on 
the channel before connecting or disconnecting its XLR input.
(d) PAD
Attenuates (lowers) the mic input signal level by 20 dB. Pad is unavailable for the line 
inputs and the Hi-Z instrument input.
(e) POLARITY Ø
Inverts the polarity (aka “phase”) of the input signal. Polarity inversion can help reduce 
phase cancellations when more than one microphone is used to record a single source.
(f) LINK
Links input channels 1 and 2 as a stereo pair. When the inputs are stereo linked, all 
input control adjustments are applied to both input channels equally. 
Note: The Hi-Z instrument input cannot be linked to a mic or line input. 
Therefore, LINK cannot be activated when a plug is inserted in the Hi-Z jack (14).
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