1. Introduction
Thank you for choosing the Lomeho LO-U78 4 Channel VHF Wireless Microphone System. This system is designed to provide unconstrained happiness and high-quality audio for various small environments such as audits, podcasts, small venue shows, karaoke, parties, and church events. It utilizes a VHF fixed frequency band (210-270MHz) to minimize interference and ensure stable performance. The system incorporates multilevel high-frequency and middle-frequency narrowband filters to dispel possible interference signals and special ALC circuitry to prevent sound loss at high volumes. All circuits use quartz crystal oscillating for steady frequency.
This manual provides detailed instructions for setting up, operating, and maintaining your wireless microphone system. Please read it carefully before use to ensure optimal performance and longevity of your product.
A PDF version of this manual is available for download here.
2. Package Contents
Please check the package carefully to ensure all items are present and in good condition:
- Receiver: 1 pc
- Handheld Microphones: 4 pcs
- Power Adapter: 1 pc
- Anti-slip Rings: 4 pcs
- 6.3mm to 6.3mm Audio Cable: 1 pc
- English Instruction Manual: 1 pc
3. Setup
3.1 Microphone Battery Installation
- Turn the microphone switch to the "OFF" position.
- Unscrew the bottom part of the microphone to open the battery box cover.
- Insert two (2) AA 1.5V batteries into each microphone, ensuring correct polarity. (Batteries are not included in the package).
- Close the battery box cover securely.
3.2 Receiver Connection
- Connect the provided power adapter to the DC 12V 1A Power Supply Port on the back of the receiver and plug it into a suitable AC 100-240V 50/60Hz power outlet.
- Turn on the electrical switch on the receiver. The power indicator light should illuminate.
- Pull out both antennas (Antenna A & B) on the receiver and position them vertically for optimal signal reception.
- Connect the receiver's audio output to your audio mixer, amplifier, or speaker system.
- XLR Outputs (Balanced A/B, C/D): Use XLR cables (not included) to connect the receiver to an audio mixer. This allows separate control of microphone pairs (A/B and C/D).
- Mix Out (6.35mm): Use the included 6.35mm audio cable to connect the receiver to an amplifier or speaker. This output combines all microphone signals, allowing only combined volume control.
4. Operation
- After connecting the receiver and installing batteries in the microphones, turn on the power switch on each microphone.
- When a microphone is turned on, the corresponding "RF" signal light on the receiver will illuminate, indicating a successful connection.
- Adjust the volume for each channel using the individual volume control knobs on the receiver.
- For temporary pauses, switch the microphone to the "STANDBY" position to prevent unwanted noise.
- The system has a working range of approximately 25 meters (30 meters if no obstacles). Ensure the microphones are within this range for optimal performance.
Note on Frequencies: There are two groups of fixed VHF frequencies for this system, and the specific group shipped is random. If purchasing multiple systems for simultaneous use, ensure they have different frequency groups to avoid interference. If using systems with the same frequency group, maintain a distance of at least 100 meters between them to prevent interference.
5. Maintenance
- Battery Replacement: If the power indicator light on a microphone dims, replace the batteries immediately.
- Long-Term Storage: If the microphones will not be used for an extended period, remove the batteries to prevent leakage and damage.
- Power Disconnection: Always pull off the power plug from the receiver when not in use for a long time.
- Environmental Care: Avoid direct sunlight, drenching, and strong electromagnetic waves. Do not place the receiver in a dead corner to maintain good signal conditions.
- Physical Handling: Do not throw the microphones, as this can cause serious damage.
- Servicing: Do not attempt to disassemble the unit yourself due to the presence of high voltage, which can be harmful.
6. Troubleshooting
Refer to the table below for common issues and their solutions:
| Malfunction | Reason | Solution |
|---|---|---|
| Power indication light darkens when receiver power switch is on | Receiver circuit is not connected | Connect the power adapter |
| No sound | Wireless microphone not turned to "ON" position | Turn microphone to "ON" position |
| No sound | No connection of receiver's audio frequency | Connect the audio cable circuit |
| No sound | The volume of receiver or amplifier is too low | Turn up the volume properly |
| Receiving distance is too short | Distance of wireless microphone and receiver is too far | Move back to the service area |
| Receiving distance is too short | Antennas of receiver are not pulled out | Pull out the antennas |
| Sound worsens | Microphone battery power insufficient | Replace the microphone batteries |
| Sound worsens | Pronouncing too loud and mouth too close to microphone | Maintain a slight distance from the microphone |
If the issue persists after attempting these solutions, please contact your dealer for further assistance.
7. Specifications
7.1 General Specifications
- Frequency Range: VHF 210-270MHz (Specific frequencies: 223.1-245.2MHz or 226.5-249.7MHz, shipped randomly)
- Frequency Stability: ±30ppm
- Frequency Response: 75-12KHz
- Dynamic Range: >80dB
- Total Harmonic Distortion (T.H.D): <1%
- Signal-to-Noise (S/N) Rate: >80dB
- Operating Temperature: 0°C - 45°C
- Service Areas (Working Range): 25 meters (30 meters if no block/obstacles)
7.2 Receiver Specifications
- Power Supply: AC 100-240V 50/60Hz
- Power Consumption: 1W
- Sensitivity: 30dB/uV
- False Rate: >70dB
- Vicinity Rate: >70dB
- Audio Output: >25mV
- Outputs: 2 XLR balanced outputs, 1 x 6.35mm mixed output
- Material: Plastic box
7.3 Transmitter (Microphone) Specifications
- Transmitter Power: 8.5mW
- Modulation Mode: FM
- Largest Modulation: ±75KHz
- Power Voltage: 2 x 1.5V AA batteries
- Power Indication: Light darkens when battery is low
- Style: Handheld Dynamic Microphone
- Polar Pattern: Cardioid
- Material: Plastic
8. User Tips
- Frequency Management: If you plan to use multiple wireless microphone systems simultaneously, it is crucial to select systems with different frequency groups to prevent interference. If systems with the same frequency group must be used, ensure a minimum distance of 100 meters (approximately 328 feet) between them.
- Battery Life: Always have spare AA batteries on hand for the microphones, especially during long events, as battery power can deplete quickly.
- Optimal Placement: Position the receiver in an open area, away from walls or corners, and ensure antennas are fully extended and vertical to maximize signal strength and range.
- Audio Connection: For professional setups requiring individual microphone control, utilize the XLR outputs to connect to an audio mixer. For simpler setups, the 6.35mm mixed output is suitable for direct connection to an amplifier or powered speaker.
9. Warranty and Support
For any malfunctions not covered in the troubleshooting section, or if problems persist, please contact your original dealer or the LOMEHO Official Store for support. Do not attempt to repair the unit yourself, as this may void any warranty and poses a safety risk.
