Distribution Amplifiers Buyer’s Guide

Sometimes you'll find that you need to send your audio signal to more than one audio device at the same time. Simply connecting them to one another will weaken the signal and degrade the sound.

Also referred to as a DA, a distribution amplifier lets you reproduce an audio or video signal from a single input and send it to multiple receiving units at one time. A distribution amp is helpful if you have a good signal at the splitter, but not after splitting. The distribution amplifier maintains the strength of received signals, ensuring all the output receivers you're using receive them at the same level without degradation of quality. They typically have very low output impedance, so changes in load won't affect the output voltage. DAs are primarily used to overcome loss of signal strength after the signal has been split to “distribute” audio or video signals to multiple locations.

Distribution amplifiers are commonly found in more permanent environments, such as recording studios, event centers, restaurants and bars and by professional media companies, to send a common audio source to several locations within an area.

Couldn't I just use a pre amp to strengthen the signal? Preamps are typically used to boost the gain of weak signals or when there are long cable runs (over 50 feet).When the coax cable run from the antenna to the TV is longer then 50 feet. If your cable runs are shorter than that and your signal is strong coming in, a preamp is probably not required.

Types of audio distribution amplifiers

Distribution amplifiers are designed for easy use. Simply connect it to your audio device via a cable. Here are a few common types of DAs used:

• Analog distribution amplifier
• Digital distribution amplifier
• Video and multi-format distribution amplifier

Analog audio distribution amplifier

Analog sound closely replicates audio signals as they are produced. Though the sound is high quality, it's easily manipulated by noise and distortion that could possibly degrade it. Analog signals are distributed by RCA cables, one of the more common audio cables you'll find. Coming in a pair of wires that are molded together, the ends separate so one plugs into the left speaker of your receiver and the other into the right. They're generally used for connecting basic home AV equipment. They come with either two, four, six or eight plugs, but remember, two plugs is the equivalent of one complete output.

Digital distribution amplifier

Digital audio can be conveniently saved to a computer. Because digital media is so easy to store and preserve - much easier than analog audio signals - it's not subject to warping or degradation over time. You'll want a digital DA if you need high fidelity audio or if your devices do not support analog inputs.

Distribution amplifiers are designed for all types of video formats. You need to make sure the DA you purchase matches the signal and cable connection of your components. The ones you're most likely to encounter are:

• VGA
• HDMI
• Component video
• Composite video
• DVI

VGA distribution amplifiers

A VGA distribution amplifier is used for transferring computer video signals to two or more monitors. They come with 2, 4, 8 and 16 ports, so you can send the same image to multiple displays.

HDMI distribution amplifiers

HDMI distribution amplifiers are used for sending high definition signals to two or more HD displays. They also come with 2, 4, 8 and 16 ports, and conveniently allow you to transfer both audio and video signals via one cable.

Component distribution amplifiers

This distribution amplifier comes with one component and 2, 4, 8 or 16 component outputs, so you can send both your high definition and analog video signals to multiple receivers.

Composite distribution amplifiers

Composite video distribution amplifiers use common RCA cables to distribute signals from one analog source to several different analog displays.

DVI distribution amplifiers

DVI DAs also send one source of high definition video to several displays. They're most often used to connect computers with DVI outputs to several DVI-compatible monitors or projectors.

Here are the main types of digital distribution amplifier cables:

• HDMI/DVI
• Digital coaxial
• Optical - SPDIF

HDMI and DVI cables

4K/ UHD support - note that 4K signals require a high bandwidth cable in order to work properly. While most cables claiming to support 4K will work fine over short distances of 10 feet or less, the choice of cable becomes much more important when looking at longer cable runs of 20 feet or more. Make sure to choose a cable that supports 18Gbs throughput.

High definition, the defacto for audio and visual signals these days, requires special HD cables. HD cables conveniently transmit high quality audio and video through one single cable. HDMI cables use 19-pin connectors when converting digital signals to analog and vice versa, eliminating the possibility of degradation. They offer up to eight channels of sound, creating a high quality, surround sound cinematic experience.

DVI cables, used with computers, also transmit HD audio and video. Special adapters are available to convert DVI signals to HDMI and HDMI to DVI.

Optical cables

Also known as fiber optic or Toslink, optical cables are incredibly common when it comes to transmitting digital audio signals. They transmit the signals as pulses of light, which helps keep them from degrading and falling prey to interference. These cables can offer up to five channels of sound. They have trouble, however, processing higher resolution sound files. While they're great for HDTVs, CD players and other home theater receivers, they wouldn't be ideal for your Blu-ray player.

Digital coaxial cable

Coaxial digital cables transmit digital data through electronic signal pulses, though they're not as commonly used as HDMI or optical cables. They're similar in design to basic RCA cables, but better shielded from interference for higher quality sound, can handle more power, and boast a wider frequency range. Digital cables also offer up to five channels of sound for a surround sound experience. They're great for home audio and theater receivers but are not usually recommended for long cable runs.

Important distribution amplifier specs

• Shielding
• Connectors

Shielding

Shielding is used to protect your audio cable's sound signal from radio frequency and electromagnetic interference, minimizing sound degradation. Cables are surrounded by layered shielding material to keep this interference from reaching the conductor.

There are three main types of shielding:

• Braided shield
• Spiral-wrapped, or serve shield
• Foil shield

Braided shield

Shielding most commonly comes in the form of a wired braid. Braided wire strands protect the cable's conductor from noise and interference. Because they can handle the wear and tear, they're perfect for live performances.

Spiral-wrapped shield

Spiral-wrapped shields - or serve shields - use flat strips of wire wrapped in a spiral around the conductor to protect the cable from sound interference. They're not as strong, and therefore slightly less resistant to signal interference compared to braided shields, but they're incredibly flexible. They're also less expensive and easier to make than braided shields.

Foil Shield

These inexpensive mylar-backed aluminum tubes have a copper wire connected at each end. Though they get the job done, they're also easily damaged. They're best used in a more permanent audio setup.

Connectors

Connectors are an incredibly important part of your audio cables, as they're the part that actually plugs into the input and output jacks of your audio equipment. They're designated as male or female. Male connectors have one or more protruding pins that go into your input; female connectors receive these conductors.

Here are a few common types of connectors:

• XLR
• RCA
• TRS/TS
• USB

XLR connectors

These are the most common connectors for professional audio setups. With a circular design around three to seven pins, they're perfect for transmitting microphone or balanced audio signals.

RCA connectors

RCA connectors are great for home audio equipment. RCA cables consist of wires molded together. The wires separate at the ends, leading to two connector heads, one red, one white or black. These connectors have an approximately 2mm outer shell that surrounds one central pin. They're easy and convenient to plug into your audio devices, with capabilities for handling a wide range of frequencies.

TS/TRS connectors

A TS connector, either a 1/4" or 1/8" plug, is commonly used with instrument cables, speaker cables or unbalanced patch cables. TRS and TS connectors are similar in design, except TRS connectors have an extra ring, which allows the connection of two wires. They're also used for balanced cable and stereo, and can be utilized as a single jack for input and output signal flow.

USB connectors

USBs have become commonplace digital computer connections, with type A or type B connectors on either end. They're used to plug instruments, speakers, MP3 players, digital audio gear and more into your computer.