ODD - Inductor EQ

A four-band inductor-based EQ. Designed to work in standard "500" racks

A modern update of the classic "swinging inputs" console EQ, with four easy to use bands. Each band uses a high quality inductor and carefully selected caps to give two switchable frequencies. The bands are carefully shaped and spaced to be musical, even at full 12dB boost or cut. The highest band can also be switched from bell to shelf, to boost frequencies extending well beyond 20kHz. There are illuminated pushbuttons for additional fixed low (red) and high (yellow) cut filters. A relay true bypass (green) allows for easy comparison with unprocessed source material. With the low and high cut switched out, and all four bands set to 0, the frequency response is +/- 0.25dB from 15Hz to 25kHz, and -3dB at 60kHz. With specialized input and output transformers, the Odd has plenty of headroom, even at full boost. The entire circuit is discrete, with no electrolytic capacitors in the signal path, and no servo amps. With only two active stages, the current draw is low enough to work in any rack, and leave plenty of juice for other modules. For easy serviceability and tweaking, the Purple discrete opamps can be replaced with any standard discrete opamp or a DIP-8 IC.

Designed by Ed Anderson for Purple Audio.

High frequency switchable from bell to shelf

High frequency 12kHz / 8kHz

Highmid frequency 4kHz / 1.8kHz

Lowmid frequency 650Hz / 300Hz

Low frequency 150Hz / 75Hz

Each band boost or cut by 12dB

Switchable High cut at 12kHz

Switchable Low cut 60Hz

True Relay Bypass

Transformer balanced in and out

Discrete signal path

No electrolytic caps in signal path