The World's Finest Tube Preamplifier

ADL 600: 2-channel High-Voltage Tube Preamp

Ultra-low-noise, with a big, warm, smooth, clear sound.

Co-designed with famed tube-circuit designer Anthony DeMaria, the ADL 600 is our top-of-the-line tube mic preamplifier. Featuring a Class A, discrete design with three top-grade vacuum tubes per channel, it uses only top-shelf components and operates with ±300V power rails for maximum headroom and superb tone. The dual-transformer design also ensures low-noise operation, with maximum common-mode rejection. The result is an ultra-low-noise tube preamp with a big, warm, smooth, clear, distinctive sound. We believe it is the best tube mic preamplifier money can buy. When you hear it, we’re confident you’ll agree.​

High-end design and components all the way.

We went high-end all the way with the ADL 600, right down to the last polypropylene film capacitor. We use only the finest components, including switched attenuators, analog VU and LED meters, and custom-designed, proprietary transformers. There are no op-amps or ICs in the signal path because they tend to add noise, coloration, and harshness. This is a boutique preamplifier, with no compromises, and it produces big, smooth, articulate vocals; deep and tight bass guitars; and rich, full mixes. The ADL 600 makes virtually anything you run through it sound better.

Read more about the ADL 600's design.

The ADL 600 preamplifier runs on power rails of ±300V. Most off-the-shelf, op-amp-based designs run on power rails of 10V to 18V. Higher-voltage power rails deliver more headroom, deeper lows, smoother highs, and a richer overall sound.

We only use genuine transistors, resistors, and capacitors in the ADL 600 because this provides ultra-low noise and transparency. Op-amps add noise, coloration, and harshness to a signal. You won’t find them in the ADL 600.

The ADL600 employs large, high quality, custom-wound, shielded input and output transformers. Among other things, these securely decouple the preamp from the outside world (the mic and the A/D or following devices), which is very important in a high-voltage tube design such as this one.

The ADL 600’s Cinemag input transformer sets the stage for the preamp’s nearly ruler-flat/linear and detailed sound; the rest of the preamp amplifies what the Cinemag delivers. No other input transformer sounds like the Cinemag does—and we tried others.

The nickel/iron-core, large-scale output transformer delivers high headroom. It will begin to saturate in a pleasing (some would say “creamy”) manner at very high levels. This adds the bit of finish to the sound.

“Full-featured” barely begins to describe the ADL 600.

Beyond superb sound quality, the ADL 600 is special because of its flexibility and extensive features. Each of the two input channels has separate mic, line, and instrument inputs, and you can select among four mic-input impedances, so the preamp works great with any type of microphone. Each channel offers a balanced XLR line-level output. You get a highpass filter, +48V phantom power, polarity inversion, and a 20 dB pad, all controlled by big, sturdy, military-grade switches. Fast-acting, eight-segment LED meters accurately detect fast transients and peaks. Large, backlit analog VU meters display output levels, and a -6 dB switch lets you meter particularly hot signals. The ADL 600 is indeed full-featured—and then some.

Learn more about the ADL 600’s features.

Most mic preamps have a fixed microphone-input impedance of between 1 and 2 kΩ. The ADL 600 provides variable microphone-input impedance, which can be set at 150, 300, 900, or 1500Ω. As the impedance on the ADL 600 is lowered, a resistive load is put on the microphone. This will not damage the microphone but lowering or raising the impedance can create subtle coloring and filtering effects, enabling you to get a wider variety of sounds.

The ADL 600’s high-pass filter employs a rotary switch with three filter settings (40 Hz, 80 Hz, and 120 Hz at 6 dB/octave) for controlling room rumble and low-frequency noise.

The input-gain attenuator is a military-grade rotary switch that provides eight 5 dB stepped increments and a total preamplifier gain of over 73 dB. The output stage is controlled by a fully variable attenuator that delivers ±10 dB of fine-tune trim adjustment, enabling you to dial in the perfect gain structure for any application. And of course, you get +48V phantom power, polarity inversion, and a 20 dB pad, controlled by big, sturdy, military-grade switches.

Hearing is believing.

Technical explanations and descriptions of features are well and nice but when it comes to preamps, hearing is believing. So try the ADL 600 at your favorite PreSonus® dealer and experience the thrill of using the world’s finest tube preamp.