The Dynamics 2806 is a single-VCA mono expander and compressor for the 500-series format. It is designed to handle a wide dynamic gamut in the most straightforward way.

The compressor reduces the gain when the sound is above a given threshold (thus reducing the dynamic range); the expander reduces the gain when a signal is below a given threshold (thus expanding the dynamic range).

The expander and compressor are independent. In both circuits, the signal feeds a filter set and then an envelope follower (rectifier). The resulting control voltage feeds two integrators (time constants) that generate two independent sidechains, both working over the VCA level. The expander sidechain monitors the VCA input signal (feed-forward), while the compressor sidechain monitors the VCA output (feedback), which can be pre-makeup or post-makeup. Even if the compressor is always after the expander, it is possible to force the expander to idle as long as the compression is active.

Features:

• Single VCA and straightforward signal path.
• Feed-forward expander and feedback compressor (pre- or post-makeup).
• Adaptive analog sidechains.
• Two compressor time constants: default (for surgical attenuation) and classic (for creative uses).
• Two filter solutions for precise sidechaining.
• External sidechain input can be routed to the compressor, expander, or summed to the internal compressor sidechain.
• Compressor priority: blocks the expander when the compressor is active.
• Reliability and easy maintenance over time.
• High-end capacitors to prevent damage followed by incorrect connections (e.g., phantom power) or defective source with DC offset.
• Active filter stages for the best performance regardless of the application environment.
• An audiophile-grade discrete output current stage specifically designed to feed a Lundahl LL1585.