Preamplifier Basics For Home Theater

What is a preamplifier?

Marantz AV7702mkII AV Preamp/Processor

D&M Holdings

A preamplifier, or "preamp" for short, is a device that connects and amplifies the audio signal from various of audio/visual source components, such as CDs, DVDs, or Blu-ray Disc players. The preamplifier can be used to switch between sources, process audio or video, and also supply an audio output signal to what is referred to as a Power Amplifier.

In a preamplifier-to-power amplifier configuration, while the preamp takes care of the input sources and signal processing, the power amplifier is the component that supplies the signal and power needed for the loudspeakers to produce sound.

This means that you cannot connect speakers directly to a preamplifier unless they are self-powered speakers that have RCA input connections. It is also important to note that AV preamp/processors provide outputs that can be connected to a powered subwoofer

Other Names For Preamplifiers

In home theater, preamplifiers may also be referred to as Control Amplifiers, AV Processors, AV Preamps, or Preamp/Processors due to their role in providing both audio decoding or processing and video processing and upscaling capabilities.

Additional Features of a Preamplifier

In some cases, an AV Preamp Processor may include the ability to be the central hub of a multi-room audio set-up, either via Multi-zone or wireless multi-room audio capability. Some are also able to accept direct streaming from Apple AirPlay or Bluetooth-enabled devices, such as many smartphones and tablets.

An AV Preamp/Processor may also be equipped with a USB port for accessing compatible digital media content directly from plug-in flash drives or other compatible USB devices.

When considering the purchase of an AV preamp/processor, make sure it has, in addition to audio, any video or networking features you may desire.

Examples of AV Preamp/Processors Include:

Integrated Amplifiers

When a preamplifier and power amplifier are combined into one unit, it is referred to as an Integrated Amplifier. In addition, if an integrated amplifier also includes a radio tuner (AM/FM and/or Satellite Radio and/or Internet Radio) then it is referred to as a receiver.

Using a Home Theater Receiver as a Preamplifier

Although home theater receivers have their own built-in amplifiers, higher-end ones often provide two or more sets of preamp outputs that connect to external amplifiers. This allows you to use the home theater receiver as a preamp to control what signals are sent to an external amp.

This comes in handy if the receiver's onboard amplifiers are not powerful enough for a newer setup. However, when a home theater receiver's preamp outputs are used, they disable the receiver's internal amplifiers for the corresponding built-in amplifier channels. This means you cannot combine the power output of the receiver's internal amplifier(s) with an external amplifier for the same channel(s).

However, some home theater receivers allow you to reassign those internal amplifiers to other channels that are not being bypassed. This feature allows you to use a mix of internal and external amplifiers to expand the number of channels that a home theater receiver can control.

In the example shown below, the home theater receiver provides preamp outputs for not only its center, left, right, left/right surround, and left/right surround back channels, but also two subwoofers, two sets of height channels, and Zone 2/3 systems.

Refer to the instruction manual for your specific home theater receiver for details on whether it offers any preamp outputs and how many.

Pioneer VSX-LX503 Home Theater Receiver Preamp Outputs
Pioneer Electronics

Blu-ray/Ultra HD Disc Players and Preamplifier Features

Another twist on the preamplifier concept is select Blu-ray/Ultra HD Disc players that provide multi-channel analog preamp outputs.

Although all Blu-ray Disc players provide digital audio outputs via HDMI and/or optical/coaxial outputs, there are some that also provide analog preamp outputs for 2, 5, or 7 channels.

These outputs can connect to a home theater receiver or a power amplifier. To provide added support, these players also include speaker and audio setup options and controls similar to what you would find on a home theater receiver or integrated amplifier, making it possible to use it directly with a power amplifier if desired.

Shown below is an example of multi-channel analog preamp outputs you might find on a high-end Blu-ray/Ultra HD disc player.

Blu-ray Disc Player Multi-Channel Analog Audio Outputs
OPPO Digital

The Bottom Line - The Choice Is Yours

Although most consumers opt to use a home theater receiver as the central hub of home theater connection and control, you do have the option of separating the functions of a home theater receiver into two separate components—an AV Preamp/Processor and a Power Amplifier. However, doing so can be a much more expensive option.

If your home theater receiver supports it, you can also use its preamplifier features to control an external amplifier(s).

The choice is up to you, but our suggestion would be to consult a home theater expert to determine what might be the best option for your specific home theater setup.