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OpenAudio L2H-1204 Audio Matching Transformer
OpenAudio L2H-1204 Audio Matching Transformer
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OpenAudio L2H-1204 Audio Matching Transformer
Based on 57 reviews
Product Overview
OpenAudio L2H-1202/1204 is a dual-channel audio line matching transformer module designed to convert low-impedance (4Ω/8Ω) amplifier outputs into standard 70V/100V constant-voltage outputs, with up to 120W output capacity per channel.
The device is widely used in commercial broadcasting and background music systems, effectively solving challenges such as long-distance transmission and multiple speaker parallel connections.
This device adopts a standard 1U rack-mounted structure with an industrial-grade shielded chassis, featuring low audio loss and high operational stability. It is widely used in shopping malls, hotels, office buildings, campuses, and industrial parks for public broadcasting systems. It is a core supporting device for implementing true constant-voltage audio distribution.
- Qobuz Connect
- Airplay 2
- Spotify Connect
- DLNA
- Bluetooth
- USB Audio Capture
Key Features
- Dual-channel independent operation: Each channel is fully isolated with a Max output capacity of 120W, supporting stereo or dual-zone applications without interference.
- Dual voltage mode switching: Supports standard 70V and 100V constant-voltage outputs for flexible deployment based on distance and speaker configuration.
- High-fidelity, low-loss design: Audio-grade transformer core with insertion loss ＜1dB and flat frequency response, ensuring accurate sound reproduction without noticeable distortion or low-frequency attenuation.
- Standard rack installation: 1U rack-mount design compatible with all 19-inch racks, enabling clean installation and efficient space usage.
- Industrial-grade reliability: Full metal shielding minimizes electromagnetic interference and ensures stable 24/7 operation.
- Easy wiring and maintenance: Removable Phoenix connectors with clearly defined input/output sections for quick installation and servicing.
4.Panel and Interface Description
4.1 Front Panel
4.2 Rear Panel Interfaces
All connections are located on the rear panel, divided into input, output, voltage selection, and grounding sections. Each channel is independent.
- CH1 Input: Connect to amplifier CH1 low-impedance output
- CH2 Input: Connect to amplifier CH2 low-impedance output
- CH3 Input (L2H-1204 only): Connect to amplifier CH3 low-impedance output
- CH4 Input (L2H-1204 only): Connect to amplifier CH4 low-impedance output
- CH1 Output: 70V/100V output to speaker line
- CH2 Output: 70V/100V output to speaker line
- CH3 Output (L2H-1204 only): 70V/100V output to speaker line
- CH4 Output (L2H-1204 only): 70V/100V output to speaker line
- Voltage Selection: Independent 70V / 100V / COM terminals per channel
- Ground Terminal: System grounding for noise reduction and safety
5.System Installation and Wiring Guidelines
5.1 System Topology
Audio Source → Power Amplifier → OpenAudio L2H-1202/1204 → Constant-voltage speaker system
5.2 Installation
- Install in standard 19-inch rack
- Place near amplifier to reduce cable length
- Ensure proper ventilation
5.3 Wiring
- Use 1.5–2.5mm² cable for amplifier input
- Select voltage mode using terminal jumpers
- Connect speakers in parallel
- Ensure proper grounding
5.4 Load Requirements
- 70V mode: ≥40Ω per channel
- 100V mode: ≥80Ω per channel
- Do not operate without load
6. Application Scenarios
6.1 Voltage Mode Selection
- 70V: short distance (<500m), dense speaker deployment
- 100V: long distance (500–1000m), wide-area coverage
6.2 Wiring Recommendations
- Input side: shielded cable
- Output side: 1.5–4mm² depending on distance
- Maintenance and Troubleshooting
Routine Maintenance
- Inspect connections regularly
- Clean dust
- Maintain proper environment
Common Issues
| Issue | Cause | Solution |
| No output | Wiring or power issue | Check connections |
| Distortion | Overload | Reduce load |
| Noise | Grounding issue | Improve grounding |
| Overheating | Overload | Improve ventilation |
- Safety Instructions
- Power off before wiring
- Do not operate without load
- Avoid overload
- Do not disassemble
- Standard Accessories
- Main unit ×1
- Rack screws ×4
- Documentation
- Engineering Notes (Critical Operation Guidelines)
The input power must not exceed the transformer’s rated power (120W per channel). For reliable long-term operation, it is recommended to operate within 70–85% of the rated capacity.
11，70V/100V Constant Voltage: Transformer-Based vs. DSP-Limited Systems
Behavior at System Limits
True Constant Voltage vs. DSP-Limited Output
How Transformerless 70V/100V Systems Actually Work
Electrical Specifications
| Parameter | Specification |
|---|---|
| Number of Channels | 2 / 4 channels (independent isolation) |
| Maximum Output Power per Channel | 120W (70V / 100V line) |
| Maximum Input Voltage | 32Vrms |
| Output Voltage Levels | 70V / 100V (selectable) |
| Audio Insertion Loss | ＜1dB |
| Frequency Response | 70Hz–15kHz (±1dB, at 1W output) |
| Compatible Input Impedance | 4Ω / 8Ω |
| Minimum Load Impedance (70V mode) | ≥40Ω |
| Minimum Load Impedance (100V mode) | ≥80Ω |
Mechanical and Environmental Specifications
| Parameter | Specification |
|---|---|
| Dimensions (W×H×D) | 209mm × 44mm × 178mm |
| 209mm × 44mm × 278mm | |
| Net Weight | 2.1kg /4.1kg |
| Gross Weight | 2.4kg /4.4kg |
| Installation | 19-inch rack, 1U |
| Chassis Material | Metal shielded enclosure |
| Operating Temperature | 0℃–40℃ |
| Storage Temperature | -20℃–60℃ |
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OpenAudio HOLOWHAS × Home Assistant Integration (Manual Install Guide) | Full Setup Tutorial
In this video, we demonstrate how to manually install and configure the official OpenAudio HOLOWHAS Home Assistant Integration.
The OpenAudio HOLOWHAS Series multi-room streaming amplifiers — including HOLOWHAS Ultra, Plus, Max, Ultra-GC, Plus-GC, and Max-GC — officially support Home Assistant, allowing seamless integration into your smart home ecosystem.
Two installation methods are supported:
• Manual Installation
• HACS Installation
This video focuses on the Manual Installation method, guiding you step-by-step through the entire process — from downloading the integration to controlling your amplifier inside Home Assistant.
Comparing HOLOWHAS and JukeAudio
| Specs | Juke-6/8 | HOLO-WHAS |
|---|---|---|
| 8 ohms power | 40W | 60W |
| 4 ohms power | 80W | 120W |
| Source In Num | 4 | 8 |
| Zones Num | 6/8 | 8 |
| SNR | 98db | 130db |
| THD+N | -92db | -120db |
Question 1: How can we use Airplay on Android device?
Answer 1: Simply install AirMusic on your Android device.
Question 2: Can we use it with more than 8 zooms with HOLO-WHAS?
Answer 2: Absolutely, you can expand beyond 8 zones, even playing the same music in unlimited different rooms with multiple HOLO-WHAS.
Question 3: Does HOLO-WHAS Ultra support USB disk playback?
Answer 3: Yes, it's a unique multi-room home sound system that supports USB disk playback, see also HOLO-WHAS Plus or Max.