Zoom AC-2 & AC-3

The main difference between the AC-2 and AC-3 is that AC-3 is meant to model another guitar than your own. (Think Fishman AURA Image Casting technology)

Zoom AC-2:
Source guitars 16 types
Sampling frequency 44.1 kHz
A/D conversion 24-bit 128× oversampling
D/A conversion 24-bit 128× oversampling
Signal processing 32-bit
Frequency characteristics 20 Hz–20 kHz (+1 dB/−3 dB) (10 kΩ load)
Input Standard mono phone jack
Rated input level: −20 dBu
Input impedance: 10 MΩ
Outputs 1/MONO/PHONES Standard stereo phone jack (combined line/headphone)
Maximum output level:
Line +7 dBu (10 kΩ or more output impedance)
Headphones 8 mW + 8 mW (32 Ω load)
2 Standard mono phone jack
Maximum output level:
Line +7 dBu (10 kΩ or more output impedance)
BALANCED OUT XLR jack
Output impedance:
100 Ω (HOT-GND, COLD-GND), 200 Ω (HOT-COLD)
PRE/POST (switchable)
GND LIFT (switchable)
S/N (equivalent input noise) 120 dBu
Noise floor (residual noise) −100 dBu
Power AC adapter: 9 V DC 500 mA center negative (ZOOM AD-16)
Batteries: 2 AA (about 3 hours continuous operation time using alkaline
batteries)
External dimensions 158 mm (D) × 107 mm (W) × 52 mm (H)
USB USB MIDI USB Micro-B
Weight 570 g (Not including batteries)

This is a fixed IRs pedal: You can not capture your own guitar IR with it. You an not load your own IR "third-party" file either.
Zoom AC-3: Same specs but:
Source guitars 16 types
Target guitars 15 types

This is a fixed IRs pedal: You can not capture your own guitar IR with it. You an not load your own IR "third-party" file either.