EAR 823 Passive Tube Mid-Range Equalizer

The recent trend towards ever-more-complicated equalizers and filters has not resulted in any real increase in flexibility, and certainly not in quality.

The EAR 823 "Pultec"-type equalizer is a relatively simple passive device that has been designed to be highly flexible and therefore genuinely useful in any application.  As always with EAR products, the highest possible sound quality is of the essence, and the filter circuits are used so as to introduce the minimum possible of disturbing side effects in the way of phase shift and ringing, thus preserving the essential qualities of the signal intact.

It is a characteristic of this device that subtle equalization changes are not masked in effect by the distortion often due to inadequate active filters.  Variations in response include low pass, high pass, band pass and high or low frequency shelf, with variable Q and turnover frequency.

The EAR 823MQ mid-EQ is a variant on the 822Q for use in the midband.  It has slightly fewer facilities but they are more closely spaced over a narrower frequency span to give greater precision in this critical part of the spectrum.

Specifications:ONS

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