INPUT - There is a single instrument input provided linked to
a PASSIVE/ACTIVE selector switch. The Passive input (switch
out) is high sensitivity and also high impedance to suit the
output from PASSIVE basses. The Active input (switch in) is
low sensitivity and lower impedance to suit the output from
ACTIVE basses.
INPUT CONTROL - The INPUT control sets the signal level
through the preamp in conjunction with the INPUT LEVEL VU
Meter. This is adjusted to give a reading of 0VU on the meter
for average playing dynamics with occasional peaks into the
red region. Please note that the setting of this may have to be
re-adjusted after modification of the EQ controls.
PUSH FLAT / SHAPE - With this button in its OUT position a
fixed E.Q. is superimposed on the preamp to give a bright but
punchy character to the sound. Pushing this button IN returns
the preamp to a Flat frequency response. This function may
also be controlled from a footswitch. For the footswitch to
operate this button must be in its OUT position.
DOOM - This routes the signal either through a clean Solid
State amplification section (control on zero) or through a
Dual Triode Tube amplification/overdrive section in order
to add either tonal character i.e. warmth with the control
set at 9 o’clock, a slight edge in the sound at 12 0’clock
through to an increasing degree of Tube distortion/over-
drive as the control is advanced to maximum.
A Mix of these two amplification sections can be achieved
with this control.
N.B. The degree of tube distortion provided by this control
will also depend on the setting of the INPUT control.
DOOM IN/OUT - This push button switches the valve drive
section IN or OUT. This function may also be controlled from
the Ashdown 4 way footswitch. For the footswitch to operate
this button must be in its OUT position.
E.Q. IN / OUT - This push button switches the Equalisation
section IN or OUT i.e. the Bass, Middle and Treble controls
plus the two sets of sliders placed between each of these.
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HEAD OF DOOM USER GUIDE:
This function may also be controlled from the Ashdown 4
way footswitch. For the footswitch to operate this button
must be in its OUT position.
9 BAND EQUALISATION - This consists of BASS, MIDDLE and
TREBLE controls with three sliders placed between each
control. This can be used in a number of ways:
Firstly as a very simple Bass, Middle and Treble tone
control section as found on older traditional amplifiers. This
is done by leaving
The two sets of sliders interposed between these controls
set in their centre positions and using only the BASS,
MIDDLE and TREBLE controls to alter the overall tone.
Secondly, if more control is required then the sliders can
also be used to tailor the E.Q. In the regions between the
main tone controls. This provides a very versatile Equali-
sation section, it is simple to understand and operate, yet
provides a wide degree of variation. It retains the simplicity
of a three- control tone section but provides the flexibility
of a graphic equaliser.
SUB HARMONICS - This section produces Sub Harmonics
an octave below the notes being played. The level of these
Sub Harmonics relative to the straight bass sound can be
adjusted using the LEVEL control.
This is very effective in thickening the sound and you will
find in use that only a small degree of this lower octave is
required to really fill out the sound and provide a character
that is not possible by any other means.
The degree of Sub Harmonics is also dependant on the setting
of the BASS control.
DIRECT INJECT (D.I.) - A balanced D.I. Is provided on a
latching XLR socket. This has a push button placed below
it that allows the user to choose either a Pre E.Q. Signal
(button pushed IN) or a Post E.Q. Post Sub and effects signal
(button OUT).
The output signal from this XLR socket is set to a level
and impedance suitable for connecting directly into the
Microphone input of a mixing desk for either Direct Injection
into the PA system or for recording. This must ONLY be used
into a Balanced Microphone input, it is not intended for any
other type of connection.
This has a floating ground that is referenced to the mixing
console it is plugged into and should not need ground lifting.
It is also unaffected by Phantom Powering on the Microphone
input. Make sure your XLR plug does not have the shell of the
plug internally connected to signal ground or this will connect
the system to chassis ground of the ABM and may cause
problems with hum.
PUSH TO MUTE - When pushed IN this button mutes the output
from the preamp to the power amp, mutes the output from
the D.I. Socket and mutes the output from the LINE Out socket
as well. This leaves the output from the TUNER socket still
available to allow muted tuning. A purple LED is provided
next to this switch to indicate when the amplifier is muted.
This function operates only from the front panel MUTE push
switch. i.e. pressing this button mutes all sound from the
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