Classic and highly regarded guitar vacuum tube preamp / processor with 2.01 Artists firmware upgrade chip, battery mod and new battery.  It's known for its strong high-gain tones and tight low-end.

Some small amount of rack ear rash, mostly covered up with the rack mount washers and bolts. Looks good overall, faceplate looks great. Everything works. This unit is USED so expect some used characteristics please.

The sound of this unit is heard ALL OVER records from the 80s and 90s metal and rock guitar driven music. They sound absolutely fantastic and are extremely versatile from clean to razor edge distortion.

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The A/DA MP-1 is a MIDI programmable tube preamp, renowned for its flexible tone shaping and use in 80s and 90s rock and metal music. It features a unique Tri-State Voicing selection (Distortion Tube, Clean Tube, and Solid State) for each program and an onboard stereo chorus. The MP-1 is MIDI-controlled, allowing for 128 programmable presets and easy integration with other MIDI devices.

Key Features:

• MIDI Programmable: Stores 128 presets for instant recall, controlled via MIDI. 
• Tube Preamp: Utilizes 2 x 12AX7 preamp tubes for a warm, tube-driven tone. 
• Tri-State Voicing: Offers three distinct voicings for each program: Distortion Tube, Clean Tube, and Solid State. 
• EQ and Presence Control: Features an EQ section designed to emulate Fender and Marshall sounds, with a Presence control for further tone shaping. 
• Stereo Chorus: Includes an analog stereo chorus circuit for adding depth and dimension to the sound. 
• Serial Effects Loop: Allows for integration of external effects pedals and rack gear. 
• MIDI Control: MIDI IN, OUT, and THRU ports for seamless integration with MIDI setups. 

Tone and Usage:

• The MP-1 is known for its ability to produce a wide range of tones, from clean and sparkly to heavily distorted and saturated. 
• It's particularly well-suited for mid-gain applications and has been a favorite for achieving classic 80s and 90s rock and metal tones. 
• The Solid State mode can be used for a clean, compressed sound, with Overdrive 1 acting as a gain control and Overdrive 2 acting as a compression control, according to a review on The Gear Forum. 

Historical Significance:

• The MP-1 was a pioneering piece of gear, combining analog tube preamp technology with digital MIDI control. 
• It was famously used by many artists in the late 80s and early 90s, including bands like Metallica and Nuno Bettencourt. 
• Its popularity solidified its place as an iconic piece of guitar gear, especially for those seeking that signature 80s/90s rock and metal sound. 

These units sound they way they do because of the extremely high tube gain they produce...which contributes to a well known and often discussed, large noise floor. If purchasing an ADA MP-1 you should also already have, or plan on purchasing a good noise gate.