Before explaining how to connect two amplifiers to one set of speakers, it might be a good idea to explain why you would want to. The main purpose of my home cinema is to watch movies in a 7.1.2 Dolby Atmos/ DTS X arrangement. While the Sony STR-DH790 AV receiver I use does a great job for movies and has more than enough power for all my speakers, it doesn’t have quite the impact I was hoping for when listening to stereo music. Therefore, I use a dedicated stereo amplifier for two-channel music. Due to limited space in my home cinema room, I wanted both amplifiers connected to my Yamaha NS-F51 speakers so I could switch between the two amplifiers.
The best way I found for doing this was by using a switch box that allows you to switch between amplifiers. The one I use is the Dynavox AMP-S Amplifier/Box Switch which has three positions, AMP 1, 0 and AMP 2. The switch box is aluminium with binding posts on the rear allowing you to connect your speaker cable with bare wire or using banana plugs which is what I use.
Setup using this method is fairly simple, all speakers apart from the front left and front right speakers are connected directly to the speaker outputs on the AV receiver. You then connect the left and right speaker output from AMP 1 to the “AMP1” input on the switch. Then connect the left and right speaker output from AMP 2 to the “AMP2” input on the switch. Ensure you have positive and negative wired up correctly, the switch has black and red rings around the binding posts to make this easier You then connect the front left and right speakers to the speaker out on the switch and you’re all set! Just ensure you have the correct amplifier selected on the switch before turning the amplifier on to avoid damage. By using this method, you may require a separate DAC as you won’t be able to use the signal processing on the AV receiver on the stereo amplifier. I use the Sony UBP-X1000ES and connect the HDMI to the AV receiver for watching movies and use the Sony’s built-in DAC and analogue outputs which are connected directly to the stereo amplifier for listening to music from digital files or CDs.
The second method is more complicated and requires an AV receiver which has pre-out connections for the front left and right speakers. Start by connecting all speakers other than the front left and right directly to the AV receiver. Then connect the pre-out left and right to the inputs on the stereo amplifier using RCA cables. The front left and right speakers are then connected to the speaker outputs on the stereo amplifier. You will also need to configure the settings to on your AV receiver to send the front left and right signal to the stereo amplifier over the pre-out connection. Using this method allows you to use the processing and DAC on your AV receiver as it is connected to the stereo amplifier.
The advantages of using two separate amplifiers are the audio is better optimised depending on what you are listening to; AV receivers are the only way to enjoy surround sound when watching TV, however when listening to music the equalisers are generally more limited compared to a stereo amplifier. AV receivers also have to share the power across more channels, whereas the stereo amplifier only has to distribute the power to two channels which results in a cleaner, more impactful listening experience. You also have the added benefit of having more analogue inputs on the stereo receiver and the phono stage for turntables are generally better on stereo receivers than they are on AV receivers. If you decide you want to change certain aspects of your setup, it is also easier to do by having two separate amplifiers.
As an example, I have listed what I have each of my amplifiers connected to as well as the Amazon.co.uk links for some of the items:
Dynavox AMP-S Amplifier/Box Switch connected to Yamaha NS-F51 floor standing speakers.
Sony STR-DH790 AV receiver- Yamaha NSP51 Speaker Package for the centre, surround left and surround right speakers as well as the Harman Kardon SAT-TS11 Satellites for the front height and Harman Kardon HKTS 210SUB Subwoofer. Via the HDMI connections I have the Sony ZF9 4K HDR TV connected via HDMI (eARC), Sony PS4 Pro, Sony UBP-X1000ES and a Dell Area 51 gaming PC.
Technics SU-V45A stereo amplifier- Sony PS-HX500 turntable using the Technics phono stage, IFI Zen Blue Bluetooth receiver, 3.5mm to RCA cable and Sony TC-188SD cassette deck. If you have any questions, please write them in the comment section below or contact us directly.