Line Magnetic LM-518IA - User Manual

INTEGRATED VACUUM TUBE AMPLIFIER
LM-518IA

Summary

Package Contents

Product Features

Key Features Overview

Lists key features and technical specifications of the amplifier.

Specification

Safety Precautions

Functions Description

Front Panel

Describes controls and indicators on the front of the amplifier, including input selector, volume knob, and meters.

Rear Panel

Details the input/output connections, speaker terminals, and power socket with fuse on the rear panel.

Overview from the top

Provides a top-down view of the amplifier's components and tube layout.

Bias Adjustment for V1, V2

Explains the procedure for adjusting bias current for power tubes V1 and V2 using the front panel controls.

Connection

Speaker Connection

Instructions for connecting speakers to the amplifier's 4, 8, or 16 ohm terminals correctly.

Audio Connection

Standard connection procedures for linking the amplifier to other audio equipment.

Turning ON

Precautions

Important safety considerations and steps to follow before and during powering on the amplifier.

Remote Control

Description

Details the functions and layout of the remote control unit, including volume and mute buttons.

Battery Installation and Replacement

Instructions for installing and replacing batteries in the remote control unit.

Tube Replacement

Maintenance

Warranty Statement

Troubleshooting

Overview

1. Technical Specifications
2. Usage Features
3. Internal Components and Construction
4. Remote Control
5. Maintenance Features
6. Troubleshooting

The Line Magnetic LM-518IA is an Integrated Vacuum Tube Amplifier designed for high-fidelity audio reproduction. It features a Single Ended Triode (SET) design, operating in Pure Class A, and delivers 22 watts per channel. The amplifier utilizes a full tube complement, including 12AX7 input tubes for voltage amplification, 6P3P driver tubes, 5AR4 rectifier tubes, and 845 output tubes. The 6P3P driver tubes are replaceable, allowing users to experiment with different tube types to tailor the sound to their preference.

Technical Specifications:

• Power Output: 22W + 22W
• Frequency Response: 10Hz ~ 50kHz (-1.5dB)
• THD (Total Harmonic Distortion): 1% (1kHz)
• Input Sensitivity: 200mV (Integrated)
• S/N Ratio (Signal-to-Noise Ratio): 87dB A Weighted
• Input Impedance: 100kΩ
• Output Impedance: 4Ω, 8Ω, 16Ω
• Tube Complement: 12AX7 x2, 6P3P x2, 845 x2, 5AR4 x1
• Power Requirements: ~230V ±5% (50Hz)
• Power Consumption: 320W
• Dimensions (WxDxH): 430mm x 365mm x 250mm
• Net Weight: 35kg
• Working Condition: Temperature: 0℃ ~ 40℃, Moisture: 20% ~ 80%
• Storage Condition: Temperature: -20℃ ~ 70℃, Moisture: 20% ~ 90%

Usage Features:

The LM-518IA offers a comprehensive set of features for versatile use within an audio system. On the front panel, it includes an Input Selector for choosing between Pre-In, LINE1, LINE2, and LINE3 inputs, allowing connection of multiple source components. A large Volume Knob controls the audio output level. An Ampere Meter is prominently displayed on the front panel to monitor the current of the power tubes, aiding in bias adjustment. An IR Remote Sensor allows for convenient control via the included remote. An Indicator for Operation/Mute shows the amplifier's status; it glows orange during normal operation and twinkles for 30 seconds during the soft start time delay or when muted. A main ON/OFF switch controls the power to the unit.

The rear panel provides four pairs of signal inputs for various sources and speaker terminals for 4, 8, and 16 ohm speakers, accommodating a wide range of speaker impedances. A Power Socket with a main fuse is located on the rear, with the fuse easily replaceable with the same type and value.

A key user feature is the Bias Adjustment for V1 and V2 (845 Power Tubes). After warming up for about ten minutes, users can select V1 or V2 on the Bias Current selector, then adjust the corresponding BIAS ADJ. knob to set the bias current. The front panel ampere meter helps monitor this adjustment, with a suggested bias value of 70mA. It is recommended to re-test the operating state of each tube after approximately 150 hours of use. The amplifier also includes an External Hum Balance adjustment for fine-tuning sound.

Internal Components and Construction:

The LM-518IA is built with high-quality components to ensure optimal performance. It features specially designed EI transformers for both power supply and output, offering wide bandwidth. A Japanese ALPS volume potentiometer and German N-cap coupling capacitors are used for their audio-grade quality. The amplifier boasts hand-made construction with point-to-point wiring, a testament to its artisanal build. A soft start and time-delay circuit (30 seconds) are incorporated to protect the tubes and internal components during power-up.

Remote Control:

The amplifier comes standard with a remote control unit (LM-02) that provides VOLUME UP/VOLUME DOWN and MUTE functions. The remote requires two AAA batteries for operation. Installation involves unscrewing the remote cover, inserting the batteries according to polarity, and reassembling the cover. For replacement, users should use new, high-quality AAA batteries to prevent leakage and avoid mixing new and old batteries.

Maintenance Features:

• Cleaning: The amplifier should be cleaned with a soft, dry cloth. Chemical cleaners are not recommended.
• Tube Replacement: The manual provides a list of common replacements for the 12AX7, 6P3P, and 845 tubes, facilitating future tube rolling or replacement.
• Safety Precautions: Users are advised to unplug the power cord if the product will not be used for an extended period. Proper ventilation is crucial to prevent overheating, and the amplifier should be installed in a well-ventilated area, at least 15cm from surrounding walls. It should not be operated unloaded or with open/shorted outputs. Liquids should be kept away from the unit. In case of issues, users should contact a qualified service technician and avoid attempting repairs themselves.
• Installation Guidelines: The amplifier should be placed on a stable, level surface, away from heat sources, and not exposed to rain or moisture. Proper connection of speaker cables, ensuring correct polarity (positive to positive, negative to negative), is emphasized to prevent noise or low-grade function. Signal cables should not be fastened together with power cables to avoid disturbance.
• Power-Up Procedure: Before turning on, all connections must be secure and the power supply stable. The power LED will illuminate upon turning on and will keep lighting up after a 30-second delay, indicating normal function. If the LED does not light up, contact customer support.
• Power Transformer Heat: It is normal for the power transformer to become hot during extended operation.
• Power Cord Connection: The power cord should only be inserted into the main socket after all other instruments are properly connected.
• Speaker Cable Disconnection: Never cut off speaker cables while the unit is ON to prevent damage.
• Re-switching On: If the amplifier is turned off, wait at least two minutes before re-switching it on to protect the tubes.
• Voltage Matching: Ensure the local voltage matches the input voltage indicated on the rear panel (230VAC ±5%) to prevent damage or reduced lifespan.

Troubleshooting:

The manual includes a troubleshooting guide for common issues:

• No Output:
  • Power cord not well-connected: Check connections.
  • Main fuse is out: Replace with the same type and value.
  • Troubles of inner parts/components: Contact local agents or company.
  • Volume is at ZERO: Turn up the Volume.
  • No signal input: Check sound source, input selection, and switch to proper input.
• Sound Distortion:
  • High input signal level: Turn down the volume.
  • Ground of input signal cable is open or bad contact: Replace the input signal cable.
  • Components or circuits in trouble: Contact local agents or company.
• Sound Field Positioning is Not Good:
  • Signal input cables or speaker cables wrongly connected: Reconnect as suggested in the manual.
  • Disturbed by external instruments: Keep away from disturbance and restart the amplifier.
• No Reaction to Remote:
  • Battery is out of electricity: Replace the battery with new ones.
  • Obstacle between remote and amplifier: Remove the obstacle.

The Line Magnetic LM-518IA is designed and manufactured with original parts, and the manufacturer is not responsible for problems or damages caused by non-original parts replacement. The product comes with a one-year limited warranty from the date of purchase, with vacuum tubes warranted for six months. This warranty is limited to the original purchaser and is void if the product has been misused, abused, damaged, or serviced by unauthorized personnel.

Line Magnetic LM-518IA Specifications