Boss AD-5 Acoustic Instrument Processor, Used The Boss AD-5 Acoustic Instrument Processor is a discontinued acoustic preamp, DI box, and multi-effects unit. 
Key Features

• Preamp Section: Specially voiced acoustic instrument preamp featuring a 4-band EQ (Bass, Middle, Treble, Presence) and level controls. 
• Acoustic Processing: Innovative "Acoustic" effect with Body and Ambience (or mic distance) controls to add natural resonance and space to piezo pickup signals. 
• Effects: Built-in Roland stereo chorus and high-quality reverb. 
• Anti-Feedback: Notch filter with adjustable frequency and depth controls to combat live stage feedback. 
• DI & Bypass: Can be bypassed to function as a dedicated Direct Injection (DI) box. 

Inputs & Outputs

• Inputs: Separate dedicated inputs for Piezo (4.7 M ohms) and Magnetic (1 M ohms) pickups. 
• Effects Insert: 1/4" TRS phone type insert jack (send/return). 
• Outputs: Stereo unbalanced 1/4" L(MONO)/R outputs and balanced XLR direct outputs. 

Technical Specifications

• A/D & D/A Conversion: 21-bit AF method (A/D) / 20-bit D/A conversion.
• Sampling Frequency: 44.1 kHz.
• Power Supply: DC 9V (AC adaptor).
• Current Draw: 300 mA.
• Dimensions: 150 (W) x 155 (D) x 65 (H) mm (approx. 5-7/8" x 6-1/8" x 2-9/16").
• Weight: 1.0 kg (2 lbs. 3 oz.).
• Optional Accessories: FS-5U, FS-5L, or FS-6 footswitches and PCS-31 connecting cord