Britannia

The Brittania is a pedal architecture developed by RunoffGroove.com for the purpose of building a sound-alike pedal of the Vox AC-30 with Top Boost amplifier. 1776effects.com developed the printed circuit board(PCB) to match the schematic developed by ROG.

Thermionic Studios has purchased this PCB and sourced the parts necessary to build this pedal. We are in the process of building the pedal and will have more to report upon completion.

Controls

• Knob 1 - Bass: Sets the amount of bass frequencies in the signal with most bass available when control is fully clockwise.
• Knob 2 - Treble: Works like an AC/30 amp by boosting treble and upper midrange while cutting bass as control is turned clockwise.
• Knob 3 - Brilliance: Sets the amount of treble after the preamp section, increasing treble as control is turned clockwise
• Knob 4 - Gain: Sets the amount of overdrive in the preamp section, increasing as control is turned clockwise.
• Knob 5 - Volume: Sets the volume level of the pedal with volume increasing as control is turned clockwise.
• Footswitch 1 - "On/Off": This switch toggles the effect on and off.

General Information

http://1776effects.com/wp-content/uploads/2015/03/Britannia-BOM.pdf

The Brittania can be powered by a 9-volt battery, or a tip-negative Boss-style 9-volt power adapter. The transistors must be biased correctly for this pedal to be as accurate sound-wise as possible to an actual Vox AC/30 amplifier.

Phase Inversion

From our examination of the schematic below, the Brittania appears to invert phase on the output as compared with the signal that goes into the pedal.

Electronic Part	Action	Phase State
Q1	Inverts	Inverted
Q2	Inverts	Reverted
Q3	Does not Invert	Reverted
Q4	Inverts	Inverted
IC1a	Does not Invert	Inverted
IC1b	Does not Invert	Inverted

This will need to be born out by testing and observation.

Pedal Manual

As of this time, 1776effects.com has not issued a separate manual on how to use the pedal. The best reference is either this wiki page, or the RunoffGroove entry on their website, or the build manual which describes the architecture of the pedal.

RunoffGroove offers the following advice when attempting to use the Britannia with a treble booster:

If you would like to use a treble booster at the input of Britannia like Brian May did into the AC-30 Normal channel, we recommend that you start with the following configuration: set the Bass control at maximum, the Treble control at minimum, and the Brilliance control at noon; adjust the Gain control as desired, and then fine-tune the sound to your liking with the Bass, Treble and Brilliance controls. Use of a flat or full frequency booster in front of Britannia will also produce some interesting sounds.

Schematic

© copyright 2013, runoffgroove.com

Artists

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Additional Sources