Symetrix 421 AGC- Leveler, Expander, Limiter
Made in USA Automatic gain controller The Symetrix 421 is a wide-range AGC-Leveler, a peak limiter, and a downward expander. The421 reduces the dynamic range of its input signal by the amount of its ratio setting. That is, if the ratio setting is 2:1, then 40 dB of input range turns into 20 dB at the output. A fast peak limiter puts an absolute ceiling on the output level so you know that peaks are held to the level that you set. A downward expander reduces the gain when signal levels fall too