1. Introduction
The LYELE FM ACOUSTICS FM255 MK2 Preamplifier is a high-fidelity audio component designed to deliver exceptional sound quality. This unit is a meticulously replicated version of the original FM ACOUSTICS FM255 MK2, aiming to preserve its renowned HIFI-level sound and internal architecture. It features remote control functionality for convenient operation.
Key features include:
- Complete decryption and replication of the original internal architecture.
- Remote control function for enhanced user convenience.
- HIFI-level sound performance comparable to the original machine.
- Circuitry and materials closely match the original design to maintain noble and elegant sound quality.
2. Setup and Connections
Before connecting your preamplifier, ensure all audio equipment is powered off. Carefully follow the instructions below for proper setup.
2.1 Front Panel Controls
- Balanced 2 Inputs: Selects the second balanced input source.
- Balanced Output Phase Switching: Adjusts the phase of the balanced output.
- Left and Right Balance Adjustment: Fine-tunes the balance between the left and right audio channels.
- Balanced 1 Input: Selects the first balanced input source.
- 3 Single-ended Inputs: Selects one of three RCA single-ended input sources.
- Tape Input: (Not enabled for operation).
- Mono: Switches the output to monaural mode.
- Volume Attenuation 20dB: Reduces the volume by 20 decibels.
- Master Volume Adjustment: Controls the overall output volume level.
- Switch: Power on/off button.
2.2 Rear Panel Connections
- 110V/220V Voltage Input: Power input connector. Ensure the correct voltage setting (100V, 110V, 115V, 120V, 220V, 230V, 240V) is selected for your region before connecting to power.
- Balanced Output: XLR connectors for balanced audio output to a power amplifier. Default is European/Japanese standard; can be switched to American standard.
- Single-ended Output: RCA connectors for single-ended audio output.
- Three RCA Inputs: RCA connectors for connecting single-ended audio sources.
- Two Balanced Inputs: XLR connectors for connecting balanced audio sources.
3. Operating Instructions
Once all connections are securely made and the correct voltage is selected, you can begin operating your preamplifier.
- Power On: Press the power switch (10) on the front panel.
- Select Input: Use the input selection buttons (1, 4, 5) to choose your desired audio source (Balanced 1, Balanced 2, or one of the 3 Single-ended RCA inputs).
- Adjust Volume: Rotate the Master Volume Adjustment knob (9) to set the desired listening level. For quick volume reduction, use the Volume Attenuation 20dB button (8).
- Adjust Balance: Use the Left and Right Balance Adjustment knob (3) to fine-tune the stereo image if needed.
- Phase and Mono: Experiment with the Balanced Output Phase Switching (2) and Mono (7) buttons to suit your listening preferences or specific audio content.
- Remote Control: The preamplifier supports remote control functionality for convenient adjustment of volume and input selection from your listening position.
4. Internal Design and Components
The LYELE FM255 MK2 Preamplifier is built with high-quality components to ensure superior audio performance and reliability.
- Audiophile-grade Audio Array Capacitors: These capacitors ensure a sufficient large dynamic voltage supply, contributing to stable and powerful sound reproduction.
Audiophile-grade audio array capacitors for stable power delivery. - Imported Original Power Transformer: The unit utilizes an imported NORATEL transformer, which contributes to a superior noise floor and overall sound quality compared to domestic alternatives.
Imported NORATEL power transformer for clean power. - Pure Copper Gold-plated RCA Sockets: Gold-plated balanced ports and pure copper gold-plated RCA sockets ensure excellent conductivity and an unobstructed signal path, preserving sound details.
Pure copper gold-plated RCA sockets for optimal signal transfer. - Japanese Original ALPS Remote Control Volume Potentiometer: This high-precision potentiometer offers excellent stability, a small temperature coefficient, reliable contact, and high temperature resistance, ensuring accurate and consistent volume control.
Japanese ALPS remote control volume potentiometer for precise control.
5. Specifications
| Feature | Specification |
|---|---|
| Gain / Maximum Input Level / Input Impedance | 20dB / 9V / 67-100-150KΩ |
| Maximum Output Level / Recommended Load Impedance | 19.5V / 600Ω |
| Inputs (Phase, Stereo) | Balanced (XLR) x 2, Single-ended (RCA) x 3 |
| Band Input and Output (Stereo) | Single-ended (RCA) x 1 (Note: Tape input/output functionality is not enabled) |
| Output (Stereo) | Balanced (XLR) x 1 with single-ended output option |
| Frequency Response | 20Hz - 40KHz |
| Power | 30W AC, 110/220V 50/60Hz (User selectable voltage) |
| Power Consumption | 10W |
| Dimensions (W×H×D) | 446 mm × 92 mm × 280 mm |
| Weight (with packing) | 8 kg |
6. Maintenance
To ensure the longevity and optimal performance of your LYELE FM255 MK2 Preamplifier, follow these maintenance guidelines:
- Cleaning: Use a soft, dry cloth to clean the exterior of the unit. Avoid using liquid cleaners or solvents, as they may damage the finish.
- Ventilation: Ensure adequate ventilation around the preamplifier. Do not block the ventilation openings.
- Placement: Place the unit on a stable, level surface away from direct sunlight, heat sources, and excessive moisture.
- Power Off When Not in Use: If the unit will not be used for an extended period, power it off and unplug it from the wall outlet.
7. Troubleshooting
If you encounter any issues with your preamplifier, refer to the following common troubleshooting steps:
- No Power: Check if the power cable is securely connected to both the unit and the wall outlet. Ensure the power switch is in the 'On' position. Verify the correct voltage setting for your region.
- No Sound:
- Confirm that the correct input source is selected on the preamplifier.
- Check all audio cables (XLR, RCA) for secure connections between the source, preamplifier, and power amplifier.
- Ensure the volume is not set to minimum or attenuated (check 20dB attenuation button).
- Verify that your power amplifier and speakers are properly connected and powered on.
- Distorted Sound:
- Check for loose cable connections.
- Ensure the input level from your source is not too high, causing clipping.
- Test with a different audio source or cables to isolate the problem.
- Hum or Noise:
- Ensure all components are properly grounded.
- Try separating power cables from audio cables to reduce interference.
- Check for faulty cables.
8. User Tips
To maximize your listening experience with the LYELE FM255 MK2 Preamplifier, consider these tips:
- Cable Quality: Invest in high-quality balanced (XLR) and single-ended (RCA) cables for optimal signal transfer and minimal interference.
- Source Matching: Ensure your audio sources (CD player, DAC, streamer) are well-matched with the preamplifier's input impedance for the best sound.
- Listening Environment: The preamplifier is designed to deliver a pure, natural, and balanced tone. A quiet and acoustically treated listening room will allow you to fully appreciate its capabilities.
- Experiment with Phase: The balanced output phase switching feature can subtly alter the soundstage. Experiment with it to find the setting that sounds best with your system and recordings.
9. Video Demonstration
Watch this video for a visual demonstration of the LYELE FM255 MK2 Preamplifier in an audio setup.
10. Warranty and Support
For warranty information and technical support, please refer to the seller's policies or contact the LYELE AUDIO DIY Store directly. Keep your purchase receipt as proof of purchase.