Signature Series Bass Amplification

Head of Doom Geezer Butler Signature Bass Amp Head

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Head of Doom

Front view - Click to enlarge [+]

Introducing the Ashdown ‘Head of Doom’ Geezer Butler Signature Bass Amp Head. Hand built in the UK, the Head of Doom was designed around Geezer Butler’s very requirements.
 
The Ashdown and Geezer Butler story began three years ago after extensive talks with Geezer’s long standing tech, Terry Welty. Black Sabbath’s ‘The End’ farewell tour was approaching and Geezer was extremely specific about his bass sound for the band’s departing tour. Ashdown designed a rig for Geezer to leave a bold statement with, encapsulating a music career spanning 50 years into one sound to remember the almighty Black Sabbath by.
 
The Head of Doom is for bass players who seek classic, driven bass tones with phenomenal power. Stripped back, the Head of Doom is built on Ashdown’s flagship ABM range; offering tried and tested tone and rock-solid reliability.
 
The Number of the Beast
 
The Head of Doom has a deadly power section rated at 666 Watts RMS with two Neutrik speakon outputs. The power section has a minimum load of 4 ohms. The slave input on the rear is designed to be fed by the transformer-isolated outputs if running multiple heads from one input source. More heads - more doom!
 
From the top, the Head of Doom features a single instrument input linked to a passive/active selector switch. The passive input option (switch out) is high sensitivity and high impedance to suit the output from passive basses.
 
Dual VU Visual Monitoring
 
Perhaps the most obvious feature on the Head of Doom is its twin set of VU meters - the first Ashdown amplifier head of its kind. Not only does the head look like a daemon on stage, the second VU meter allows for output level visual monitoring. Now bass players can find the sweet spot for their instrument via the familiar input level VU. From there the player can tweak their tone via an experienced 9-band EQ and use the shape control to further sculpt their tone, all the while monitoring the output level at the same time via the second VU.
 
Added Doom
 
The ‘Doom’ control increases the current to the amp’s 12AX7 pre-amp valve stage, like voltage through an electric chair, resulting in the richest harmonic distortion designed specifically for bass guitar. Used in conjunction with the amps impressive EQ section, there isn’t much this amp can’t deliver.
 
The Doom level control can be pre-set and kicked in and out via footswitch.
 
Versatile EQ

The Head of Doom features a sophisticated 9-band EQ, with familiar Bass, Middle & Treble controls and six sliders allowing precision cut and boost in the regions the standard controls can't reach, providing a huge range of tonal variation and the tailring of the perfect tone.

The EQ can be switched in via footswitch taking the player from a flat fretless sound to their favourite EQ setting instantly. 
 
Sub-Harmonic Doom
 
Once heard – never forgotten. The Sub-Harmonic generator adds an octave below the notes being played bringing fullness to any bass part. The Sub level is independently controllable, thickening the sound and providing more DOOM to your tone as required.

Sub Harmonics are also controllable via footswitch.
 
Professional Connections
 
The Head of Doom is loaded with connectivity. A tuner output, line out, transparent FX loop and a line input for the connection of an external sampler or sound source. Output muting cuts the signal from the DI output but leaves the tuner output 'live', allowing the player to tune up in silence. The Head of Doom's ins and outs continue even further, as mentioned earlier, with three dedicated transformer isolated outputs with the option to slave from the dedicated slave input.

Please see the illustration below, this feature was added so Geezer could power his 12 on stage cabinets ensuring the quality of signal was maintained.


Head of Doom Specifications

Power Output 600watts RMS into 4 ohms.
Power Requirement 115 - 230 Volts
Speaker Configuration 2 x Neutrik Jack/Speakon outputs
Frequency Response -3dB an 17Hz and 22kHz
High Instrument Input Impedance 3.9m Ohm / Input range 50mV to 15V p-p
Low Instrument Input Impedance 10k ohms / Input range Input range 300mV to 30V p-p
Line Input Impedance 22k Ohms / Input level 0dBu nominal
Line Output Impedance 10K Ohms / Level 0dBu nominal
DI Output 600 Ohms balanced / Level -20dBu nominal With Ground Lift
Tuner Output Impedance 22k Ohms, level 0dBu nominal
Impedance Minimum 4 Ohms
EQ 9-Band
Effects Send Impedance 22K Ohms / Level 0dBu nominal
Pre-Amp Tubes 1 x 12 AX7
H x W x D (mm) 127 x 431 x 279
Weight (kg) 31lbs / 14kg