If I connect 2 amps to 1 speaker what are the dangers?
I use a a big-box Blue-Ray receiver to power my 4.2 system. I may love my subs but my neighbours are not impressed. My original satellites have been replaced with bookshelf speakers. Turning subs off at night is not a good option as the crossover frequency is too high (120hz).
I have no plans to use 2 amps at the same time. When my home theatre system is off I want another amp to provide a full range signal to the front satellites.
Is this okay?
I use a a big-box Blue-Ray receiver to power my 4.2 system. I may love my subs but my neighbours are not impressed. My original satellites have been replaced with bookshelf speakers. Turning subs off at night is not a good option as the crossover frequency is too high (120hz).
I have no plans to use 2 amps at the same time. When my home theatre system is off I want another amp to provide a full range signal to the front satellites.
Is this okay?
You can't have one amp powering the speakers and have the other amp hooked up to those speakers, but have it turned off. Back feeding the output from one amp to the other, regardless of whether it's on or off, will damage both or one of the amps.
Why not just use a selector switch of some sort?
Why not just use a selector switch of some sort?
Mainly because of wires and ugly connectors. Excessive wires are responsible for more divorce settlements and alimony payments than any other reason.
- Okay, that's probably not true but it sounds accurate.
Two IDENTICAL amplifiers can power a single speaker but they must have the same power supply. The signals to one amplifier must be out of phase with the other signal. This means, when one signal is negative the other must be of the same magnitude but opposite in polarity. This method of connecting a speaker is known as BTL (bridge tied load). ICs exist which provide a BTL connection with the proper inputs taken care of by the circuitry of the IC. There are also professional amplifiers which can be used as a BTL. The signal handling to the inputs is provided automatically and is set by using arrays of small PCB mounted switches.
Not meaning to go off-topic but I would run my satellites full range all the time and use spatial means to cross the sub in.
If the amps are next to each other and you want to run 1 set of speaker cables to the speakers then build a tiny box next to the amps with a pair of DPDT switches, using the common terminals to go to each speaker, switching between amps.
If the amps are not close to each other and you need to run 2 sets of speaker cables to the speakers then put one switch on the back of each speaker.
If the amps are not close to each other and you need to run 2 sets of speaker cables to the speakers then put one switch on the back of each speaker.
Absolutely not. 😀
- If you ever had both on at the same time, even when not playing music the slightest voltage differences can cause large current flows damaging the amps and possibly cables.
- The output impedance of an unpowered amplifier is not well defined. That is, we don't really study amps in their off state, and different circuits may have different impedance to ground. Your ideal state would be having an amp that has a very high (20kOhms) impedance when off. That's not nearly guaranteed. When on amps typical output impedance is 80 milliohms or less.
- Yon can't even do this if the amplifiers are in the same chassis. That is, you should not do this by using the L and R sides of the same stereo amplifier, because even with millivolt differences (common at idle) currents want to be infinite.
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You can connect two amplifiers to one speaker if both amplifiers have a speaker protection relay that will open the relay contacts and disconnect the output when the amplifier is turned off.
However, if both amplifiers are accidentally turned on at the same time, serious damage will occur!
A switcher is the safest way to connect 2 amplifiers to 1 speaker.
However, if both amplifiers are accidentally turned on at the same time, serious damage will occur!
A switcher is the safest way to connect 2 amplifiers to 1 speaker.