If I have two stereo amplifiers connected to one pair of speakers, do I have to disconnect the speaker cables from the unused (shut off) amp? I am not concerned with switching of the amps right now, as one or the other amp will always be off.
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You dont have to, but you absolutely should unless both amplifiers have output impedances a few dozen orders of magnitude greater than your speakers.
If the unused amp does not have a protection relay to disconnect the speaker out from the active devices, definitely.
"Specifically, you should NEVER:
Run speaker wire from two amplifiers to one set of speakers at the same time without using the correct amplifier switching box – even if you are only using one amp at a time."
Message received loud and clear. I'm not connecting two amps at once even if one is shut off.
But out of curiosity, what would happen if I did? Has anyone done it?
It's something that I would instinctively never consider doing.
I presume the switched off amplifier may become part of the working load for the active amplifier.
With what result? Blown fuses, going into protection mode or even magic smoke?
I presume the switched off amplifier may become part of the working load for the active amplifier.
With what result? Blown fuses, going into protection mode or even magic smoke?
It is a situation that is easy to solve using a double inverter key, of good amperage, of the kind used for electricity.
Common sense indicates that the amplifier that is idle should be turned off. But even if it is solid state, there will be infinite load on the output (open circuit), which is not a problem. If it were a tube amp, no-load output would be risky for it.
Common sense indicates that the amplifier that is idle should be turned off. But even if it is solid state, there will be infinite load on the output (open circuit), which is not a problem. If it were a tube amp, no-load output would be risky for it.
When an amp is turned OFF , its output transistors are STILL connected to speaker terminals.
The active amp will then "see" and try to drive, not only the speaker, but a bunch of diodes and Zeners connected to it, with disastrous results.
The active amp will then "see" and try to drive, not only the speaker, but a bunch of diodes and Zeners connected to it, with disastrous results.
The outputs can never be identical, and there is a tiny impedance between them. You could cause significant damage in an instant.
JM, yes, that is in the event that the two amplifier outputs come together, but with the double inverter key they can never come together.
One amplifier remains connected and the other always disconnected at the speaker outputs.
I've used that setup for years, never a problem.
One amplifier remains connected and the other always disconnected at the speaker outputs.
I've used that setup for years, never a problem.
Two of these double inverters must be used, one for each channel, then the (+) and (-) of each speaker are disconnected and connected simultaneously.
I have searched the web and in my files, without result, I will make the sketch and upload it if necessary.
I have searched the web and in my files, without result, I will make the sketch and upload it if necessary.
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We call that a DPDT switch. The center-off feature is not needed.
If you use a 4PDT switch, you will only need one.
If you use a 4PDT switch, you will only need one.
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The attachment should help with the wiring.
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" La función de centrado no es necesaria. "
Of course, it is the internal diagram of the double inverter that I found on the web.
On one occasion I had two switches in use, one for the HT system that selected the front speakers, the rear speakers, and the subwoofer.
The other two speakers and two subwoofers dedicated to music exclusively.
Here is the most basic and conventional diagram, the one the OP is interested in, a set of speakers and two amplifiers.
There is a color error in the positive of the left channel of amplifier 2, (red / green mix) but it does not change the connection that is correct.
Reversing keys are 10 Amps.
The other two speakers and two subwoofers dedicated to music exclusively.
Here is the most basic and conventional diagram, the one the OP is interested in, a set of speakers and two amplifiers.
There is a color error in the positive of the left channel of amplifier 2, (red / green mix) but it does not change the connection that is correct.
Reversing keys are 10 Amps.
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Actually it can be worse than this - if its got a protection relay it may well have the outputs switched to ground when not powered up, thus blowing up the other amp by direct short.