GDI21 Guitar Amp Modeler/DI by Behringer

The Behringer GDI21 Guitar Amp Modeler/DI is a high-quality guitar modeling driver designed for hands-on musicians and no-frills types. It features different circuitries and components from famous amps packed into one housing, allowing users to alternate between various amp re-creations, gain settings, and mic placements with minimal effort. The GDI21 also functions as a standard ultra-transparent direct injection box when used in bypass mode.

Key Control Elements:
1. DRIVE control: Adjusts the overall amount of gain and overdrive.
2. TREBLE control: Governs the high-frequency range of the signal (±12 dB).
3. BASS control: Allows boosting/cutting of the low-frequency range (±12 dB).
4. LEVEL control: Adjusts the output level of the GDI21.
5. AMP switch: Selects one of three classic tube amps - TWE(E)D, BRIT(ISH), or CALIF(ORNIAN).
6. MODE switch: Dials up one of three gain settings (HOT, HI G(AIN), CL(EA)N) to combine with the amp setting.
7. MIC switch: Simulates microphone placement (CL(AS)SIC, C(E)NT(E)R, OFF (A)X(IS)) in relation to the cabinet.
8. GND LIFT: Disconnects the ground connection between input and output to eliminate hum or ground loops.
9. Footswitch: Activates/deactivates all tone functions (EQ, DRIVE, modeling).
10. LED: Illuminates when the effect is activated.

Connectors:
11. ¼" TS INPUT connector: For instrument cable connection.
12. BAL OUT: Balanced mic level output.
13. ¼" TS OUT connector: Sends the signal to a guitar amp.
14. SERIAL NUMBER: Located at the bottom.
15. BATTERY COMPARTMENT: For installing or replacing the 9V battery.
16. DC IN connection: For plugging in a 9V power supply (not included).

Specifications:
- Input Impedance: 1 MΩ
- Output Impedance: 1 kΩ
- Balanced Output Impedance: 200 Ω
- Power Supply: 9V, >50 mA DC regulated
- Power Consumption: 25 mA
- Dimensions (H x W x D): Approx. 5 x 3 9/10 x 2" (127 x 100 x 50 mm)
- Weight: Approx. 1.01 lbs / 0.46 kg

The GDI21 is suitable for stage, recording, rehearsal, or warm-up, offering an arsenal of different tones for all players.