Our SUS kits bring the sound’s 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. 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; this is the part of the sound our SUS kits affect.
Available Kit Configurations:
SUS-1 is for non-Power Scaled, fixed-bias amps. It is a compression side-chain that can be fitted into any fixed-biased amplifier that does not already have Power Scaling. This circuit works around the output stage only. A non-critical 16mm pot provides continuously variable compression for any signal level. Depending on how the bias supply is generated in the amplifier, our RBX Raw Bias Auxiliary Supply Kit) may be required for proper functioning of SUS-1. Please contact us with any questions.
SUS-2 is suitable for cathode-biased amps. It can be used in single-ended or push-pull amplifiers, regardless of whether they are Power Scaled. It can be fitted to any cathode-biased power amplifier or preamp gain stage, allowing high-bias amplifiers with no inherent sag to exhibit compression effects more akin to fixed-biased amplifiers. A non-critical 16mm pot provides continuously variable compression for any signal level.
SUS-3 is specifically designed for fixed-biased amplifiers fitted with Power Scaling. It 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. The addition of our RBX Raw Bias Auxiliary Supply Kit) 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 is included, as well as notes including installation tips and layout + schematic diagrams of the kit.
Assembly is required.
For more info, see “Sag/Sustain Kit Selection“.