A preamplifier, or preamp for short, is a device that connects and amplifies the audio signal from various 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 supply an audio output signal to what is referred to as a power amplifier.

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

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

Other Names For Preamplifiers

In a 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 setup, either via multi-zone or wireless multi-room audio capability. Some can also 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:

  • NuForce AVP18
  • Onkyo PR-RZ5100
  • Outlaw Audio Model 975
  • Marantz AV7705
  • Marantz AV8805
  • Yamaha CX-A5100

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, satellite radio, or internet radio), it is referred to as a receiver.

Using a Home Theater Receiver as a Preamplifier

Although home theater receivers have built-in amplifiers, higher-end ones often provide two or more sets of preamp outputs that connect to external amplifiers. This setup 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 aren’t powerful enough for a newer setup. However, when a home theater receiver’s preamp outputs are used, the outputs disable the receiver’s internal amplifiers for the corresponding built-in amplifier channels. This means you can’t combine the power output of the receiver’s internal amplifier with an external amplifier for the same channel.

However, some home theater receivers allow you to reassign those internal amplifiers to other channels that aren’t 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 its center, left, right, left/right surround, and left/right surround back channels, in addition to 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.

Blu-ray/Ultra HD Disc Players and Preamplifier Features

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

Although all Blu-ray Disc players provide digital audio outputs via HDMI or optical/coaxial outputs, some also provide analog preamp outputs for two, five, or seven 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.

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 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 more expensive option.

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

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.

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