MICROPHONE PREAMBLE Dual channel preamplifier, 19'' rack mountable (1U). Lundahl LL1538 input transformer, currently the best input transformer on the market. Up to 80 dB of clean, distortion-free gain. The acclaimed ISA topology is also a guarantee of low noise, even at the highest gain levels. The transformer alone provides 20 dB of gain, while the ISA input stage provides an additional 60 dB. Four selectable input impedances that guarantee a perfect match between the preamp and your mics, including those classified as 'classics', thus allowing you to obtain a perfect sound. User-calibratable 8-segment LED meters provide a clear view of signal level and align analog levels with those of the DAW's converters via a rear-panel calibration button to prevent input clipping. Instrument inputs in 6.35 mm jack format on the front panel and TRS line inputs on the rear panel with input selector on the front panel. Extremely smooth-sounding 18dB/octave variable-cut high-pass filter that faithfully reproduces the design of the original ISA 110 module, ideal for removing rumble, thump and other unwanted low-frequency sounds thanks to its 16Hz to 16Hz range. 420 Hz. Balanced insert points on the rear panel for connection of external processors.