Elysia's mpressor 500 compressor is a forward-thinking machine designed to provide the user with both potent classical dynamics processing capabilities as well as unconventional tools to produce thick and punchy sounds not possible on other devices.
 
Engineered for creative bus and track mixing, the mpressor 500 was created for professional engineers looking for something a little different from the standard compressor unit. The mpressor 500 features typical compressor controls such as attack, release, threshold, and gain, but also includes a number of innovative custom analog circuits to provide a truly astonishing level of control over input signals.

A THD boost circuit is included, which raises the level on the input, helping to saturate and color the harmonic structure of input signals without touching dynamics. Compression ratios that stretch into the negative values (allowing for extreme "destruction" of input signals), an incredibly wide frequency response, and a unique limiter placed directly in the control circuit are just a few of the impressive and unorthodox features that make the mpressor 500 one of the most flexible 500 series rack-mounted compressors available.
 
Powerful Dynamic Control Gain Reduction Limiter
Rather than being placed directly in the signal path like most limiters, the mpressor 500's distinct gain reduction limiter is placed in the unit's control path. When activated, the GR limit control knob will directly modify the control voltages of the compressor, allowing interesting effects, such as ducking or upward compression, to be achieved without sacrificing the dynamics of loud sections.
 
Negative Compression Ratios
Unlike most compressors, the mpressor 500 can access negative ratios, which lower the output signal as the input signal increases. This is perfect for creating powerful and inventive compression effects, which become more controllable when paired with the gain reduction circuit.
 
Auto Fast 
One of the most useful features of the mpressor 500 is the auto fast circuit, which helps regulate attack dynamics. While most compressors require a user to dial in a static attack speed based upon the overall dynamics of a track or mix, the auto fast can automatically adjust the attack speed based directly on the impulse signal, becoming faster and louder with corresponding impulse transients without any manual adjustment required.
 
Anti-Log
The anti-log circuit allows the user to change the release compression scheme from linear to antilogarithmic. A useful resource for when creative compression or unconventional sounds are desired, this function results in a longer release time when the compression threshold is first passed and shortens when the input signal begins to decline, the opposite of standard compression behavior. This process is independent of the signal gain reduction, producing the same curve at the start of compression regardless of gain reduction.
 
THD Boost
Activating the THD boost function raises the level in front of the gain control element, influencing the sonic character of the input signal by generating additional harmonics. As the mpressor 500 is a pure feed-forward compressor, this allows the intensity of the resulting saturation to be raised or lowered by the gain control pot. As the sidechain detector runs parallel to this input, the signal can be colored as much or as little as you want without influencing the compression levels, allowing you to paint your tones without touching dynamics.
 
Engineering Sophisticated Creativity Dynamic Analog LED Meter
While most meters for judging gain reduction lack real-time accuracy due to needle inertia or abrupt value changes in LEDs, the mpressor 500 solves this limitation with a special analog circuit that dynamically adjusts to the signal with incredible precision. Rather than simply flickering on or off, the LED meter utilizes its purpose-built driver to display intermediate values by modulating the brightness of the LEDs, ensuring smooth and obvious transitions from one value to the next.
 
Discrete Class-A Topology
The entire mpressor 500 circuit board is built with custom-designed discrete components. This includes the full audio path, sidechain, power supply, and even the driver for the analog LEDs. The unit's PCB even comes with a special sixth layer dedicated to acting as a ground shield, avoiding any unwanted noise interference. The compressor always operates in Class-A mode ensuring minimal distortion and a warm, pristine, and punchy sound.
 
Transconductance Amplifier
The mpressor 500 features a discrete and temperature-compensated transconductance amplifier, which contains a pair of differential transistors that use a modulated current source to alter the amount of amplification. Put simply, this ensures that the circuit avoids any unwanted noise or external influence and can respond very quickly to control voltages, allowing for incredibly fast attack rates and changes in dynamics. This runs parallel to the sidechain path and makes sure that background noise always stays at the same level regardless of amplification level.
 
Sensational Build Quality
With an extreme eye for detail, elysia has ensured that the mpressor 500 is made to the highest build-quality standards. Proudly engineered and made in Germany, elysia utilizes only custom-designed parts and every unit is handcrafted to order and tested in their headquarters in Nettetal, Germany.