SUS-3 - Sustain & Compression Enhancer for Fixed Bias with Power Scaling


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The SUS-3 is specifically designed for fixed-biased amplifiers fitted with Power Scaling.

The signal envelope has three parts: the initial transient, the sustain portion, and the decay. The transient is about twice the amplitude of the sustain portion and is the part of the sound SUS effects. SUS brings the transient amplitude down to the sustain level, effectively lengthening the sustain time - but only by a short time. This is a subtle effect that alters note attack.

SUS-3 takes advantage of unique connection possibilities provided by the Power Scale circuitry itself. A non-critical 16mm pot provides continuously variable compression for any signal level. The compression will maintain its proportion as the Power Scale control is manipulated.

Addition of our Raw Bias Auxiliary Supply Kit (RBX) will assure proper functioning of SUS-3 to full power. Where the bias supply might have been "adequate" to achieve Power Scale functioning, SUS-3 requires that the raw bias supply be a bit higher voltage.

PCB included, as well as notes including installation tips + layout and schematic diagrams of the kit.

Assembly is required.

For more info, see "About Our Sag & Sustain Kits".

About London Power

London Power was founded in 1990 by Kevin O'Connor, after two decades of research into innovative audio amplification techniques. Kevin is an audio designer, author and speaker, known for his proprietary methodology called Power Scaling, and for his eleven books on audio subjects. Whether you seek amps, kits or information, you'll find useful answers here on not just the "how" but the "why" of audio amplifier design. Please enjoy the information on this site, and don't hesitate to contact us with questions.

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