A tube-driven channel strip, the ADL 700 from PreSonus integrates a boutique-quality preamp, a custom-designed FET compressor, and a custom, four-band, semi-parametric EQ. The preamp features a Class A, discrete design that utilizes two 6922 and one 12AT7 vacuum tubes operating with ±300V power rails for maximum headroom. A dual-transformer design ensures low-noise operation, with maximum common-mode rejection. Unit is housed in a two rack space rugged steel chassis.
An input select switch allows all three inputs, microphone, line and instrument, to remain connected at all times while the microphone input has a choice of four impedance values. In addition, the unit provides variable input gain, using an eight-position, military-grade rotary switch that provides 35 dB of gain in stepped 5 dB increments. A trim potentiometer provides fine adjustments of +/-30 dB to the final preamp input stage. The output stage is controlled by a fully variable attenuator that provides trim adjustment.
The compressor includes fully variable attack, release, threshold, ratio, makeup gain, and bypass controls, and features a "soft knee" compression curve. Two units can have their compressors linked for achieving accurate stereo compression. A four-band semi-parametric EQ combines isolated filters and optimized per-band Q to provide subtle signal-shaping without harsh artifacts. All bands have 16 dB of cut or gain and frequency controls, with overlapping frequency ranges and fixed bandwidth (Q). The low and high bands are switchable between shelving and peak.
The EQ position in the signal chain can be switched to either pre- or post-compressor and front panel switches can bypass either or both. Phantom power is available, as are a 20 dB pad and polarity reverse. Fast-acting, eight-segment LED meters accurately detect fast transients and peaks. Large, back-lit, dual-mode analog VU metering enables monitoring of output and gain-reduction levels. A -6 dB switch offsets the meter for use with hot source signals and a master level control adjusts the overall output from -80 to +6 dB.