aion AURUM Handmatig - Pagina 2

Blader online of download pdf Handmatig voor {categorie_naam} aion AURUM. aion AURUM 12 pagina's. Based on boss od-2 turbo overdrive

1 Project Overview

2 Introduction & Usage

INTRODUCTION

The Aurum Amp Overdrive is based BOSS

Boss's "discrete op-amp" circuit topology which uses two JFETs and a PNP transistor to create a variable

gain stage that can be controlled like an op-amp but clips gracefully when overdriven. As a bit of trivia,

the OD-2 is also one of only three fully discrete circuits ever made by BOSS (no op-amps), alongside the

FZ-3 Fuzz

and the DS-2 Turbo Distortion.

The OD-2 was first released in 1985 as the successor to the OD-1. In 1994, it was replaced by the OD-

2r. The "r" in this case stands for "remote", since it allowed an external footswitch to change between the

two channels on the fly. However, the OD-2r also corrected one one of the most persistent flaws of the

original unit, which is that it could barely get to unity gain at the highest volume setting.

The Aurum is more specifically based on the "Turbo" mode of the circuit, adapting the OD-2r version

of the circuit with the gain recovery stage and a couple of other minor tweaks. The non-"Turbo" mode

is a completely separate drive circuit within the pedal, and generally speaking it's unremarkable when

compared to the Turbo mode.

The OD-2 was officially succeeded by the OD-3 in 1997, although the BD-2 Blues Driver can be seen as

a "rebranded" in-between member of the same series since it shares much of the same circuitry as both

the OD-2 and OD-3. However, all three circuits sound pretty different, and they each bring their own

character to the table.

The original OD-2 uses the 2SK117-GR JFET, a low-cutoff type similar to J201, but no longer made in

through-hole format. 2SK209-GR is the SMD version that is still in production and will perform exactly

the same as the originals. Each of the JFETs have extra pads for soldering SMD parts, but if you don't

feel confident in your SMD skills, Aion FX sells

through-hole applications.

USAGE

The Aurum has three controls:

• Drive increases the gain of the first discrete op-amp stage, which overloads the second stage and

pushes it into clipping.

• Tone is a passive treble cut after the second gain stage.

• Volume sets the overall output of the effect signal.

AURUM AMP OVERDRIVE

12 Licensing

OD-2 Turbo Overdrive, notable as the first appearance of

2SK209-GR pre-soldered to adapter boards

to be used in

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