Zapco Harmony HB-104D II 4-Channel Full-Range Class-D Micro Power Amplifier

Compact Power & Clarity: Zapco Harmony HB-04D II

Product Overview

Upgrade your in-car listening experience with the Zapco HB-104D II full-range Class-D amplifier. Combining a space-saving micro chassis with robust power performance, this 4-channel unit delivers 100W x 4 RMS @ 4Ω and 140W x 4 RMS @ 2Ω, with bridging capabilities up to 280W x 2 RMS @ 4Ω—making it a perfect choice for upgrading door speakers or running a 3-channel front stage + subwoofer setup.

Key Features & Highlights

• High-Efficiency Class-D Output: Delivers 560W RMS total power with low heat dissipation and high efficiency in a compact footprint.

• Flexible Output Configurations: Delivers 100W x 4 @ 4Ω, 140W x 4 @ 2Ω, and bridges to 280W x 2 @ 4Ω.

• Seamless Integration: Features both RCA Low-Level and High-Level Speaker inputs for easy connectivity to factory radios or aftermarket head units.

• Variable Crossover Control: Integrated electronic crossovers allow fine-tuning with selectable High-Pass (HPF) and Low-Pass (LPF) modes.

• Micro Form Factor: Measures just 180 mm x 115 mm x 45.5 mm, fitting effortlessly under seats or behind trim panels.

Technical Specifications

• Brand: Zapco

• Series: Harmony Blue

• Model: HB 104D II

• Amplifier Topology: Full-Range Class D

• Channels: 4-Channel

• RMS Power Output @ 4 Ohm: 100 Watts x 4

• RMS Power Output @ 2 Ohm: 140 Watts x 4

• Bridged Power Output @ 4 Ohm: 280 Watts x 2

• Frequency Response: 20 Hz – 20,000 Hz (±1dB)

• Signal-to-Noise Ratio (S/N): > 90 dB

• THD + Noise: < 0.1%

• THD @ Rated Power: < 0.5%

• Input Sensitivity: 0.25V – 6.0V (Low-Level RCA)

• Input Types: RCA Low-Level & Speaker High-Level Inputs

• Crossover Control: Variable Electronic High-Pass / Low-Pass Crossovers

• Dimensions (L x W x H): 180 mm x 115 mm x 45.5 mm (7.08" x 4.52" x 1.79")

Frequently Asked Questions

1. What is the Zapco Harmony HB-104D II?
The HB-104D II is a compact 4-channel full-range Class-D car amplifier designed to power multiple speakers efficiently while offering flexible installation options.

2. How much power does the HB-104D II produce?
It delivers 100W RMS × 4 at 4Ω, 150W RMS × 4 at 2Ω, or 250W RMS × 2 when bridged at 4Ω.

3. Can I use the HB-104D II with my factory car stereo?
Yes. It supports both RCA and speaker-level inputs, making it suitable for systems using either aftermarket head units or compatible factory stereos.

4. Can this amplifier power four car speakers?
Yes. Its four-channel configuration makes it suitable for powering four speakers, subject to their impedance and RMS power requirements.

5. Can the Zapco HB-104D II power component speakers?
Yes. It can be used with compatible component speaker systems. Before installation, match the speakers' impedance and RMS power handling with the amplifier's output.

6. Can I bridge the channels for more power?
Yes. The amplifier can deliver 2 × 250W RMS bridged at 4Ω, allowing compatible speaker configurations to receive more power from two bridged channels. Professional installation is recommended.

7. Does the HB-104D II have a built-in crossover?
Yes. It features a variable electronic crossover with HP, Full and LP modes, with a crossover frequency range of 30Hz–250Hz.

8. Is the HB-104D II suitable for upgrading a factory audio system?
It can be a good option when you want more amplifier power while retaining a factory head unit, particularly because it accepts speaker-level inputs. Proper speaker matching and installation are important.

9. Is this amplifier suitable for adding a subwoofer?
It can be used for compatible full-range or subwoofer applications depending on the system configuration. For a dedicated high-power subwoofer setup, a suitable mono or dedicated bass amplifier may be a better choice.

10. How compact is the Zapco HB-104D II?
The amplifier measures approximately 170 × 115 × 45.5 mm, making it relatively compact and useful where installation space is limited.

11. What impedance can the HB-104D II handle?
It is specified for 4Ω and 2Ω operation, with different RMS power outputs at each impedance. Always confirm the speaker wiring and final load before installation.

12. Do I need professional installation for this amplifier?
Professional installation is recommended, especially when integrating it with a factory stereo, configuring speaker-level inputs, bridging channels, or setting gain and crossover correctly.

13. Will this amplifier make my car speakers louder?
The amplifier can provide substantially more dedicated power than many factory systems, but the actual improvement depends on your speakers, head unit, installation, gain settings and overall audio setup.

14. How do I know if the HB-104D II is compatible with my car?
Check your existing stereo outputs, speaker impedance, available installation space and speaker RMS ratings. If you're unsure, provide your car model, existing head unit and speaker model to an automotive audio specialist before ordering.

15. Is the Zapco HB-104D II a good choice for a car audio upgrade?
It can be a strong choice if you need a compact 4-channel Class-D amplifier with RCA and high-level inputs, flexible crossover controls and up to 150W RMS per channel at 2Ω.