The original Custom built 56-channel inline console in Conny Plank's Studio:
I like the look/layout of this dual slot unit. The global 5/15db gain switch for the eq gain is a great feature. The individual bypass switches for each band makes for easy A/B comparisons and there's selectable I/O gain. Also note the frequency switches on the hi-mid and lo-mid bands.
ZÄHL EQ1 Features:
- stereo design for mixing & mastering as well as voices & instruments
- highly musical design
- intuitive, user-friendly, self-explaining layout
- lowest noise and distortion signal paths built with highest quality components
- audio switching on EQ gain potentiometer, zero position for bypassing unused stages
- no microprocessor, no clock pulses, sequential logic only
- individual power stabilization on each module, no switched power circuitry
- fully compatible with API 500 module series specs, occupying two slots
Here's a video of Michael Zahl with the EQ1(in German) at Musikmesse 2014 and a 2nd one of the AM1 console on which it is based: