Samson MLI1 - User Manual

MLI1 Mono Isolation Box
Quick Start Guide
Callouts
1. INPUT Jack – XLR - 1/4” combo input jack for connecting line level signals. The MLI1 can
accept balanced and unbalanced connections.
2. OUTPUT Jacks – Balanced XLR and 1/4” outputs for connecting to a PA system, mixer or
recording interface. The outputs are wired in parallel so you should use only one OUT jack at a
time. The MLI1 outputs can be balanced or unbalanced connections.
3. GROUND LIFT – When the switch is in the LIFT position, the input ground (shield) is
disconnected between the INPUT and OUTPUT jacks. When the switch is in the GROUND
position, the ground is connected through the INPUT and OUTPUT jacks.
If you have two pieces of equipment in a sound system connected to ground through different
AC mains, it can cause a ground loop, which is an annoying 50 Hz or 60 Hz (depending on your
location) hum noise. When the Ground Lift switch on the MLI1 is set to the LIFT position, it breaks
the ground connection between the input and output audio jacks, thereby isolating the output from
the input and removing the hum from an audio signal path. Since both pieces of equipment are still
grounded to the AC mains, they are still safe to use.
The Ground Lift Switch
The Samson MLI1 is a line-level passive isolation box designed to remove
hum and buzz caused by ground loops, or convert unbalanced to balanced
signals. The premium circuitry with a flat frequency response from 10
Hz – 35 kHz (±0.2dB) and durable, roadworthy construction providing
high-quality signal connection solutions for live, broadcast and studio
applications.
The MLI1 transformer delivers an extended, flat frequency response and
ultra-low distortion. The Ground Lift switch isolates the ground from the
Input and Output connections which eliminates hum caused by ground
loops.
If you have any questions or comments regarding the MLI1 Passive
Isolation Box or any other products from Samson, do not hesitate to
contact us at support@samsontech.com.
With proper care and maintenance, your MLI1 Passive Isolation Box will
operate trouble-free for many years. Should your MLI1 Passive Isolation
Box ever require servicing, a Return Authorization (RA) number must
be obtained before shipping your unit to Samson. Without this number,
the unit will not be accepted. Please visit www.samsontech.com/ra for an
RA number prior to shipping your unit. Please retain the original packing
materials and, if possible, return the unit in its original carton. If your MLI1
Passive Isolation Box was purchased outside of the United States, contact
your local distributor.
Introduction
12 3

Summary

Samson MLI1 Introduction

MLI1 Component Callouts

Input Jack

Describes the XLR-1/4" combo input for line level signals, accepting balanced/unbalanced.

Output Jacks

Describes balanced XLR and 1/4" outputs for connecting to PA systems, mixers, or recording interfaces.

Ground Lift Switch Function

Isolates input ground from output to eliminate hum caused by ground loops.

MLI1 Setup and Usage

MLI1 Technical Specifications

Overview

1. Function Description
2. Usage Features
3. Maintenance Features

The Samson MLI1 is a versatile line-level passive isolation box designed to address common audio issues in live, broadcast, and studio environments. Its primary function is to eliminate hum and buzz caused by ground loops, which are a frequent source of unwanted noise in audio systems. Additionally, the MLI1 can convert unbalanced audio signals to balanced signals, and vice-versa, offering flexibility in connecting different types of audio equipment.

Function Description

At its core, the MLI1 utilizes a premium transformer to achieve its isolation and signal conversion capabilities. This transformer is engineered to deliver an extended and flat frequency response, ensuring that the audio signal remains true to its original form without coloration or degradation. The ultra-low distortion characteristic of the transformer further contributes to high-fidelity audio transmission.

The primary mechanism for hum and buzz elimination is the Ground Lift switch. When engaged, this switch effectively isolates the ground connection between the input and output stages of the MLI1. Ground loops typically occur when two pieces of audio equipment are connected to different AC mains outlets, creating a potential difference in their ground references. This difference can lead to an annoying 50 Hz or 60 Hz hum (depending on the local AC frequency). By breaking the ground connection within the MLI1, the device prevents this ground loop from forming, thereby removing the unwanted noise from the audio signal path. It's important to note that while the ground connection within the audio signal is lifted, both pieces of equipment remain safely grounded to their respective AC mains, ensuring user safety.

Beyond noise reduction, the MLI1's ability to convert between balanced and unbalanced signals is a significant feature. Unbalanced signals, often found in consumer-grade audio equipment, are more susceptible to noise over longer cable runs. Balanced signals, on the other hand, use a differential signaling method that inherently rejects common-mode noise, making them ideal for professional applications and longer cable distances. The MLI1 acts as a bridge, allowing users to integrate unbalanced sources into balanced systems or vice-versa, without compromising signal integrity.

Usage Features

The MLI1 is designed for straightforward integration into any audio setup. Its compact and durable, roadworthy construction makes it suitable for both fixed installations and mobile applications.

To use the MLI1:

• Initial Setup: Before connecting any cables, it is recommended to turn down the volume controls of all audio systems involved to prevent any sudden loud noises.
• Input Connection: Connect your audio source to the MLI1's INPUT jack. This is a versatile XLR - 1/4" combo jack, capable of accepting both XLR and 1/4" connectors. The MLI1 can handle both balanced and unbalanced input signals.
• Output Connection: Connect the MLI1's OUTPUT to the input of your audio device (e.g., a PA system, mixer, or recording interface). The MLI1 provides both XLR and 1/4" TRS output jacks. These outputs are wired in parallel, meaning you should use only one OUT jack at a time. Like the input, the outputs can deliver either balanced or unbalanced connections, depending on the receiving device's requirements.
• Level Adjustment: Once all connections are made, gradually raise the level of your audio system to the appropriate listening or recording level.
• Ground Lift Application: If you encounter a hum or buzz in your audio signal after making the connections, activate the GROUND LIFT switch by setting it to the LIFT position. This action will disconnect the input ground (shield) from the output ground, effectively breaking any ground loops and eliminating the noise. If no hum is present, the switch can remain in the GROUND position, which connects the ground through both input and output jacks.

The MLI1's flexibility allows it to be used in various scenarios:

• Unbalanced to Balanced Conversion: Connect an unbalanced source (e.g., a guitar amplifier's line out, a consumer audio player) to the MLI1's input, and connect the MLI1's balanced output to a professional mixer or PA system.
• Balanced to Unbalanced Conversion: Connect a balanced source (e.g., a professional mixer's output) to the MLI1's input, and connect the MLI1's unbalanced output to an unbalanced input device.
• Ground Loop Isolation: Insert the MLI1 between any two line-level devices that are experiencing ground loop hum, regardless of whether the signals are balanced or unbalanced.

Maintenance Features

The Samson MLI1 is designed for long-term, trouble-free operation with proper care and maintenance.

• Durable Construction: The unit features a durable, roadworthy construction, ensuring it can withstand the rigors of live performance and studio use.
• Cleaning: For general cleaning, it is recommended to use a soft, dry cloth. Avoid using harsh chemicals or abrasive cleaners, as these could damage the finish or internal components.
• Troubleshooting: If you experience any issues with your MLI1, Samson provides support resources. For common problems like hum or buzz, ensure the Ground Lift switch is correctly utilized. If further assistance is needed, Samson's support team can be contacted via email.
• Servicing and Returns: Should the MLI1 require servicing, a Return Authorization (RA) number must be obtained from Samson prior to shipping the unit. This ensures proper tracking and processing of the repair. It is crucial to retain the original packing materials, including the carton, as these are ideal for safely shipping the unit. For international customers, it is advised to contact their local distributor for servicing inquiries. Samson's commitment to continuous product improvement means that specifications and images are subject to change, but the core functionality and reliability remain consistent.

Samson MLI1 Specifications