A receiver acts as the central hub for a sound or overall entertainment system. You hook up all your components to it – the speakers, tv, media player, etc. – and it makes them all work together. As such, the receiver does several jobs that are required for any system to function, and can also have an array of additional features as you go higher end.
One such necessary job is powering the speakers – virtually every modern receiver has a built-in amplifier to do this. There might be such a thing as an “amp-less” receiver, maybe called a “pre-receiver,” but this would be a highly niche/specialized piece of equipment that few people could ever make use of.
Once a signal is amplified and powerful enough to actually move the components of a loudspeaker, it will run to the terminals on the receiver, which look something like this:
On the bottom left you can see this product has binding posts and spring clips, both of which are common connector types for speakers.
Most decent receivers can supply 80-100+ watts per channel, which is more than enough to power the vast majority of non-commercial grade systems, so an added amplifier wouldn’t actually do anything – it would be like turning on a flashlight during a bright sunny day.
That said, it is possible to run into a situation where your receiver might not provide enough power to your speakers, and – contrary to seemingly common belief – too little power is what can risk damaging speakers rather than too much power. Some examples of what might create said situation:
- Speakers with a very high RMS power rating and/or low impedance.
- A lot of speakers hooked up to the receiver, utilizing all available channels, Dolby Atmos for example.
- A large room with longer wire runs, since power wanes over longer distance travelled.
This is when an additional external amplifier might be called for to make up the difference in necessary power. One thing to note is that the original receiver will need to have “pre-out” terminals, which send an unamplified signal, in order to pair with an external amp, and this is something you wont start to see until you look at higher end products.
As you can see, this product has a much more extensive input panel then the aforementioned Sony one does, and in the middle you can see the additional pre-out terminals for the various speakers.
Here’s an example of the back panel of a 3 channel amplifier that’s pretty straightforward: connect the pre-out lines from the receiver on top, then connect the speakers to the standard looking binding posts on the bottom.
What you can do if, say, you have very demanding left/right/center main speakers, is connect them to an external amplifier, then connect that to the left/right/center pre-out terminals on your receiver, then connect the remainder of the speakers to the regular terminals and have the receiver’s amp solely power those remaining speakers.
But again, that would provide a lot of power that only the few people that really want to annoy their neighbors would ever need.