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Gain Controls
The red pot provides up to +75 dB of gain,
whilst the black pot provides a variable
mix of 2nd to 3rd order harmonics (once
the VHD-IN switch is engaged).
The grey pot pr/- 20dB of trim.
Use this to control the output when driving
the VHD preamplifier circuit.
High Pass Filter
The High Pass Filter section is a
switchable 18dB/Octave variable filter.
See the block diagram for the position in
the circuit.
Line In/DI Jack Socket
The front panel 1/4” Tip/Ring/Sleeve
(TRS) Jack Socket provides a convenient
way to connect instruments when the
module is fitted in a rack.
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This balanced input overrides the rear XLR and has a 10KΩ input
impedance and features a -10dB level pad to allow for typically
louder balanced line level signals. The Jack input can also be used
with unbalanced (TS) cables. The input level and impedance are
switched to 0dB and 1MΩ respectively (for very high impedance
sources such as guitar pick-ups) with selection of the HI-Z switch.
Input Impedances
The rear XLR and front Jack inputs have different impedances
available by using the Hi-Z switch and allow for a wide variety of
sources. The XLR input impedance changes from 1.2 KΩ to 10KΩ
and the front panel Jack changes from 10KΩ to 1MΩ.
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