HDP 4 is a D-Class four-channel amplifier, perfect to satisfy any need. It is the most compact HDP, nonetheless, like the other models, it can reach very high power levels. In less than 30 cm (12 inches), it can provide up to 1000W on 2 channels at 4 Ohm. It can be used in full range as well as with crossover settable as Lo-Pass/Hi-Pass.

It has been thought to offer the user the maximum possible flexibility, both thanks to Speaker In and RCA inputs and to the controls, with a status monitor communicating to the user through a LEDs system. Using Speaker In inputs, the ART™ ( Automatic Remote Turn On-Off) function is available, the user can also switch it off.

HDP 4 is the perfect choice for those who look for performance and non-bulky sizes. The double-extrusion heat sink and the Hertz logo, which is back lit and can be rotated, allow especially sophisticated installations.

1. Thermally optimized double extruded heatsink, ergonomic and aluminium die-cast end caps
2. 4 LEDs monitor the status of the amplifier and communicate with the user
3. Special balanced input circuitry to reject electromagnetic disturbances present on the Pre-amplified or Speaker level inputs
4. HDP Input featuring either Speaker In (OEM radio) and RCA In (Aftermarket radio) inputs
5. ART™, Automatic Remote Turn-On/Off function, automatically turns on and off the amplifier when the OEM radio turns on and off (available on Speaker In only)
6. Full range Pre-out, also available when using Speaker Level In inputs
7. 12 dB/Oct. continuously adjustable (50 to 5k Hz and 80 to 3.3k Hz) active crossover with Lo-Pass/Hi-Pass or Full Range settings;
8. A/B Input switch eliminates the need for RCA Y-Adapters
9. Power supply stage featuring multiple winding transformer, Low-ESR 105°C capacitors, D-Class 2 Ω stable output stage based on solid T220-5pin power Mosfets

Power Supply

• Power supply voltage: 11÷15 VDC 
• Idling current: 1,5 A
• Idling current when off: 0.04 mA
• Consumption @ 2Ω, 14.4 VDC (Max Musical Power): 50 A 

Amplifier Stage

• Distorsion - THD (100 Hz @ 4Ω): 0.08 %
• Bandwidth (-3 dB): 5 ÷ 55k Hz
• S/N Ratio (A weighted @ 1 V): 100 dB
• Damping factor (100 Hz @ 4Ω): 50
• Pre-In sensitivity: 0.3 ÷ 5 V RMS
• Pre-In impedance: 15 kΩ
• Speaker-In sensitivity: 1.4 ÷ 24 V RMS
• Speaker-In impedance: 470 Ω
• Load impedance:
• 4 Ch 2Ω
• 3 Ch 2 x 2Ω ÷ 1 x 4Ω
• 2 Ch 4Ω

OUTPUT POWER (RMS) @ 14.4 VDC, THD 1%

• 4 Ch: 150 W x 4 (4Ω)
• 4 Ch: 250 W x 4 (2Ω)
• 3 Ch: 150 W x 2 (4Ω) + 500 W x 1 (4Ω)
• 3 Ch: 250 W x 2 (2Ω) + 500 W x 1 (4Ω)
• 2 Ch: 500 W x 2 (4Ω)

Inputs/Filters

• Inputs: Pre IN / Speakers IN
• Outputs: Pre OUT
• A Ch Filters: Full/Hi-Pass/Lo-Pass 50 ÷ 5k Hz (2 range) @ 12 dB/Oct.
• B Ch Filters: Full/Hi-Pass/Lo-Pass 80 ÷ 3.3k Hz @ 12 dB/Oct.

Size/Weight

• Maz size (mm/inches): 171 x 284 x 46.70 / 6.73” x 11.18” x 1.83”
• Weight (kg/lb): 2.45 / 5.4 

Other Functions

• Remote In: 6 ÷ 15 VDC - 1 mA
• ARTTM: Automatic Remote Turn-On/Off with Speaker-In 
• Fuse: 2 x 40 A