PERELANDRA BOOST / OVERDRIVE
2
TABLE OF CONTENTS
1
Project Overview
7
Drill Template
2
Introduction & Usage
8
Enclosure Layout
3-5
Parts List
9
Wiring Diagram
6
Build Notes
10
Licensing
7
Schematic
10
Document Revisions
INTRODUCTION
The Perelandra Boost / Overdrive is a recreation of the Xotic BB Preamp, a flexible tone machine that
lets you go from a clean volume boost to a nice smooth overdrive with a 2-band EQ to shape the tone. It
was first released in 2005, a few years after the AC Booster and RC Booster, and the “BB” refers to the
Marshall Bluesbreaker amplifier.
Despite the name, the BB Preamp has nothing to do with the Bluesbreaker pedal. In fact, like the AC/RC
Booster, it’s very similar to the Ibanez Tube Screamer, but with an active Baxandall tone control added
before the output buffer so that the treble and bass can be independently boosted or cut.
In fact, if you look at the schematic for the BB Preamp, you can see that the original Tube Screamer tone
control stage is left intact, but with the tone knob is fixed at 5% rotation (i.e. almost fully to the dark side
of the control) by using a 1k and a 18k resistor. The main difference between the BB Preamp and the AC
or RC Booster is the presence of this Tube Screamer tone control stage to shape the tone going into the
Baxandall EQ.
Version 2 of the Perelandra is a full redesign based on traces of several versions of the BB Preamp in
2021. The PCB supports the standard BB Preamp (called the “version 1.5”), the AT (Andy Timmons)
model, and the Bass BB Preamp. Instructions have been provided for each variant. The default is version
1.5, the current production model.
The
is hot-rodded version that incorporates modifications from the two Custom
Shop models of the BB Preamp, the “MB” (mid boost) and “Comp” versions. Since it’s a lot more complex,
we’ve split it off into a separate project. While the Deluxe version can emulate either the 1.5 or AT with
the right control settings, the bass version is not supported and can only be built on this PCB.
USAGE
The Perelandra has four controls:
•
Gain
controls the amount of gain from the op amp that is fed through the feedback clipping diodes.
•
Treble
is one half of the Baxandall tone control, allowing you to boost or cut high frequencies.
•
Bass
is the other half of the Baxandall tone control, allowing you to boost or cut low frequencies.
•
Level
sets the overall output of the effect.
