Presonus ADL 600 Stereo Tube Mic Preamp - Used  From Presonus

The ADL 600 is a high voltage two-channel original microphone preamplifier designed by world-renown analog tube circuit designer Anthony DeMaria. The ADL 600 utilizes a unique high voltage, Class A discrete design with three vacuum tubes per channel for maximum headroom and tonality. The ADL 600 is built by hand in the USA by PreSonus and utilizes the finest components in the world including switched attenuators, military-grade vacuum tubes, analog VU and LED meters, custom-designed proprietary transformers, and the list goes on. No expenses are spared with the ADL 600 down to the last polypropylene film capacitor. The ADL 600 is big, warm, smooth, and clear; a sound like no other.

Control and Flexibility
The ADL 600 is designed for ultimate sonic performance, however its ease of use and flexibility allowing for many types of input sources further sets it above all other preamplifiers. The input selector allows for selection between Hi-Z instrument input, line input and four different microphone impedances for a wide variety of sounds and applications. The High Pass Filter is a rotary switch with three filter settings (40Hz, 80Hz, and 120Hz @ 6dB per octave) for passively and unobtrusively controlling room rumble and low frequency noise. The input gain attenuator is a military-grade rotary switch delivering 5dB step increments and a total preamplifier gain of over 72dB. The output stage is controlled by a fully variable conductive plastic attenuator delivering +/-10dB of fine tune trim adjustment to "dial-in" the perfect gain structure for the application at hand. The ADL 600 also includes 48V phantom power and a -20dB pad both controlled by big sturdy military grade switches.

Under the Hood
The ADL 600 is built with the finest components available in the world. The ADL 600 is a fully discrete transformer input and output Class A design incorporating three military-grade vacuum tubes per channel operating at voltages of +/-300V power rails for maximum tube tonality and headroom. There are no op-amps or integrated circuits (IC's) in the signal path to ensure the purest sound possible. The dual transformer design also ensures ultra low noise operation with maximum common mode rejection.

Metering
The ADL 600 is loaded with both fast-acting eight-segment LED meters for accurately detecting fast transients and peaks, as well as large high quality analog VU meters for metering output level.

Features:
- High-Voltage Class A Dual Transformer Design
- >73dB Gain
- Selectable Microphone Input Impedance - Switched Gain and Variable Fine Trim Controls
- Microphone, Instrument and Line Inputs
- Ultra Low Noise (-100dB S/N ratio)
- Variable High Pass Filter, 48V, -20dB Pad, Polarity Invert
- Analog VU and Fast-Acting LED Metering