L'823 si diversifica dall' 822 per il controllo delle frenquenze medie ma segue gli stessi principi.

SPECIFICHE
Operation Passive equaliser with balanced valve output amplifier
Input and output impedance 600 ohm nominal, balanced and floating
Maximum output level (1% distortion) +25dBm
Low boost & cut frequencies 20, 30, 60, 100Hz; 0, +14, - 18dB variable
High boost frequencies 3k, 5k, 7k, 10k, 12kHz; 0, +18dB variable
High cut frequencies 6k, 10k, 20kHz; shelf 0, - 18dB variable
Bypass switch no level change, clickless