Having an additional integrated amplifier to your AV receiver can be great if you want to drive more power to the speaker, especially the front speakers.
This can also help you expand your home theater surround system.
So here is a step by step process on how you can add an external amplifier to your system;
1. Locate the AV receiver’s pre-outs
Pre outs on an AV receiver are used to add external amplifiers to add more power to the home theater/media room speakers. The audio signals, therefore, pass through the receiver without amplification to an external amp.
They are commonly found in most high-end and some mid-range receivers. Different receivers will have the preouts in different locations at the back of the receiver.
Here are some of the common preouts and their uses;
- Sub-woofer preouts– Mainly used to send low-frequency signals to the subwoofers for better bass. The sub preout is mainly connected directly to an active sub(s) without the need for an external amplifier. Your receiver may have 1,2 or more outputs for the subwoofer preout section but there is only one LFE channel.
- Front left (FL) and right preouts (FR) or (front)– Are mainly used to send signals for the left and right channels to the amp for more power (better soundstage). These are the receiver preouts that are used in most scenarios.
- Center preouts (C)– Send signals for the center channel to an external amp for more power to the center channel.
- Surround preouts or surround (SR and SL) and surround back (SBR and SBL)– Can be used to send surround signals to an external amp if you want more power for the surround speakers.
- Zone 2 and zone 3 preouts (multi-zone)– Allow you to connect to an external amplifier to send sound signals to a different room(s).
You can locate these preouts at the back of your receiver for the various channels. Some receiver may also color code the left and right channels differently but the white color code is mainly used for the left channels and red for the white channels (check your user manual for more info).
2. Connect your RCA cables to the receiver preouts
Depending on the channels you want to drive more power to, you can connect the channel to the respective inputs (line-level inputs) on the external amplifier using RCA cables.
For example, if you are only using the external amplifier for the front soundstage, you will only need to connect the FR, FR, and C channel preouts to the respective inputs on the amp. This will ensure that you have a soundstage with a superior sound.
You can also connect the left and right channel preouts to the bypass inputs on the integrated amp for uncompressed stereo sound. This will only be useful if the integrated amp has a bypass input.
3. Connect the speakers to the external integrated amp
You can now connect your speakers to the integrated amp for the respective channels making sure that you match the polarity between your amp and speakers. Then go to your system and balance the sound for the various channels.
Do you need to add an external amp to a receiver?
The answer will depend on the following;
- How loud you listen to your speakers.
- Your speakers load impedance.
- How big or small your home theater room is.
- Bass management.
The table below should help you make a better decision
| Factors | Low | Mid | High |
| How loud you listen | 60 to 70 decibels | 75-85 decibels | More than 85 decibels |
| Speaker load impedance | 8 ohms > 90 decibels | 8 ohms < 90 decibels | 4 ohms < 90 decibels |
| Your room’s size | Less than 1500ft³ | 1500 to 3000ft³ | More than 3000ft³ |
| Bass management | Using a dedicated sub | Full range bass on speakers | |
| Verdict | Do not add an external amp | You can use your receiver alone or add an external amp | Add an external amplifier |
What are the pros and cons of using a receiver’s preouts to add an external integrated amp?
Pros
- Improves your ability to expand your surround sound system. You can reroute the unused receiver outputs to power other speakers like the height speakers for Dolby Atmos and height modes or to another room (zone). The connection possibilities are endless and you can customize your setup according to your preference.
- Reduces the strain on your AV receiver which improves its efficiency as it powers fewer channels.
- Improved sound quality for your home theater system by improving the sonic character of the room.
Cons
- Powering more amplifiers will means that your system consumes more power which drives up the power cost.
- AV receivers with preouts are more expensive than those without preouts.
- Additional cables can make cable management more confusing.
- Possible sonic inconsistencies due to the use of different amps for the different speaker channels. This should not be an issue for an average home theater user but to an audiophile, it will.
How can I connect an amplifier to a receiver without preouts?
If your Receiver does not have preouts, you can use a speaker to RCA line-level converter that is mostly used for car audio. A speaker line-level converter converts a speaker output to an RCA pre output signal.
Therefore, to connect an integrated amplifier to a receiver without preouts you would hook up the converter to the receiver’s speaker output for the channels you want to add more power to then hook up the converter’s RCA cables to the external amplifier. The wires are color-coded to use a guide as to where you can plug in everything and this is usually white/black for the left channel and red for the right channel.
Can I use a receiver as an external amplifier?
A receiver is basically an integrated amplifier with lots of other controls for both audio and video that means that you can use a second receiver as an external integrated amplifier. To do this you would need to clear the setting on the second receiver.
This would not be so ideal but is doable.
