Presonus ADL600 (2 channel High Voltage Tube Preamplifier)

2 channel High Voltage Tube Preamplifier

Simply the Best

We make some very good tube preamps, and we are confident that you enjoy using them. But the ADL 600 is at another level. Rumor has it that some people are willing to sell their left eyeball to get one. And while we don’t accept eyeballs as payment, we do agree that the ADL 600 is the finest tube preamp money can buy. Not the finest for the price. The finest—period.

Designed with famed tube-circuit designer Anthony DeMaria, the ADL 600 employs a distinctive Class A, discrete design with three top-grade vacuum tubes per channel, operating with ±300V power rails for maximum headroom and superb tone. The dual-transformer design also ensures low-noise operation, with maximum common-mode rejection.

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. We went high-end all the way, right down to the last polypropylene film capacitor.

The result is an ultra-low-noise tube preamp with a big, warm, smooth, clear, distinctive sound. It produces big, smooth, and articulate vocals; deep and tight bass guitars; and rich, full mixes. It makes virtually anything you run through it sound better.

↓ Read more about the design.

Maximum Flexibility

Beyond superb sound quality, the ADL 600 is special because of its ease of use and flexibility. 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.

↓ Read more about variable microphone-input impedance.

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.

We didn’t skimp on metering either. 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.

Hearing is Believing

Technical explanations are well and nice but hearing is believing. Try the ADL 600 yourself and experience the thrill of using the world’s finest tube preamp.

• 2 input channels, each with:
  • Mic, line, and instrument inputs
  • High-voltage, Class A, dual-transformer, vacuum-tube preamp
  • 3 military-grade vacuum tubes
  • Input-source select
  • Variable mic-input impedance (150, 300, 900, 1,500Ω)
  • Variable high-pass filter (40, 80, 120 Hz)
  • 8-position Gain switch
  • Variable Trim adjustment for final stage
  • 48V phantom power
  • -20 dB pad
  • Polarity-reverse switch
  • Backlit VU meter (output level) with -6 dB switch (for metering hot signals)
  • > 73 dB of gain
• Input/Output
  • 2 unbalanced ¼” instrument inputs (front panel)
  • 2 transformer-balanced XLR line inputs
  • 2 transformer-balanced XLR mic inputs
  • 2 transformer-balanced XLR line outputs
• Physical
  • 2U 19” rack-mountable, rugged steel chassis
  • Internal power supply with standard IEC connector
  • Chassis-ground link connectors (lift chassis ground)

Input Impedance
Microphone	Selectable, 150/300/900/1500Ω
Balanced Line	2 kΩ
Instrument	100 kΩ

Maximum Input Level
Microphone (1500Ω, +20 dB Pad out)	+5 dBu
Microphone (1500Ω, +20 dB Pad in)	+25 dBu
Balanced Line	+30 dBu
Instrument	+30 dBu

Gain Range
Microphone (1500Ω, +20 dB Pad out)	18 dB to 72 dB
Balanced Line	-12 dB to 40 dB
Instrument	-5 dB to 42 dB

Performance
Noise Floor (all inputs, minimum gain)	-95 dBu (A-weighted)
Microphone Equivalent Input Noise (EIN)	-125 dBu (A-weighted)
Frequency Response	10 Hz to 45 kHz ±1 dB
Maximum Output Level	+23 dBu (@ 0.5%THD+N)
Output Impedance	600Ω
Tube Complement (per channel)	1-12AT7A, 2-6922

Power
Internal supply, standard IEC connector	115 or 230 VAC / 100W

Physical
Dimensions	2U rackmount
Height	3.5” (88.9 mm)
Depth	17″ (431.8 mm)
Width	19” (482.6 mm)
Weight	28 lb. (12.7 kg)