Aion Electronics Isotope Manual

Aion Electronics Isotope Manual Manual pdf 2 page image

ISOTOPE AMP OVERDRIVE2TABLE OF CONTENTS1 Project Overview 7 Enclosure Layout2 Introduction & Usage 8 Wiring Diagram3-4 Parts List 9 Licensing5 Schematic 9 Document Revisions6 Drill TemplateINTRODUCTIONThe Isotope Amp Overdrive is an adaptation of the “Tube Voice” channel of the Intersound InstrumentVoicing Preamplifier, a rack preamp from the late 1970s that was favored by Steve Albini and theGrateful Dead among others.The IVP’s Tube Sound channel was unique in its method of overdriving the signal. There are no diodesto be found, but rather, the signal is clipped by overloading a miniature transformer. Add in a two-bandtone control and you’ve got a really flexible circuit that doesn’t look or sound quite like anything else.The Isotope Amp Overdrive is a greatly reduced version of the IVP, extracting just the Tube Voicechannel which makes up approximately 25% of the whole preamp circuit, which also includes a cleanchannel and 4-band parametric equalizer. It’s been adapted to run off of +/-9V instead of +/-15V like theoriginal. However, all the character of the drive channel is retained and it makes a great standalone drivepedal if you want something a little different!One thing to mention: the Treble knob can create oscillations at the very high end of rotation. We triedseveral things to mitigate this during development, including better power filtering and tweaking thevalues of the treble control, even a new PCB layout, but nothing really fixed it. However, since it onlyimpacts the last 5-10% of the rotation which is really outside the useful range of the control, we optedto release it as-is.USAGEThe Isotope has the following controls:• Drive controls the amount of gain in the op-amp stage that is fed into the transformer. Overloadingthe transformer pushes it into clipping.• Treble is a half of a Baxandall tone stack affecting the high frequencies.• Bass is the other half of a Baxandall tone stack affecting the low frequencies.• Master controls the overall output of the effect.