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Looking for help ensuring speakers are these suitable for these amps.
This thread has 18 replies. Displaying posts 16 through 19.
Post 16 made on Wednesday January 20, 2021 at 22:39
buzz
Super Member
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On January 20, 2021 at 21:51, Ernie Gilman said...
Now I'm wondering what point you're trying to make....

There is a misconception that an amplifier "pushes" power to the speakers. The physics is that the amplifier output voltage varies (up to it's maximum) and there is an output current limit.

It's really no different from an AC power circuit or a 70V line. A certain voltage is available and each connected device draws some current. For example, on a 120VAC power line, a certain current is available, perhaps 15A. We can keep adding lamps until we reach the 15A limit.

The difference between a lamp circuit and our speaker circuit is that the lamp circuit operates at a constant voltage and our amplifier's output voltage varies with the Volume control setting and the musical content.

In our speaker circuit there are two limits -- the maximum current the amplifier can deliver and the maximum voltage that the speakers can handle. In a lamp circuit we can dim a lamp (operate at a lower voltage than the lamp is rated), but if we supply a higher voltage than the lamp rating, the lamp dies.

Part of the problem is the math that we use for our speaker circuits. If we used the same math approach for AC power circuits, we'd be struggling to figure out how many 144 Ohm lamps we could stack on our 1800 watt power line.
Post 17 made on Thursday January 21, 2021 at 00:55
tomciara
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On January 20, 2021 at 22:39, buzz said...
There is a misconception that an amplifier "pushes" power to the speakers. The physics is that the amplifier output voltage varies (up to it's maximum) and there is an output current limit.

I will defer to your expertise, but in amplifier theory I believed that the preamp stages up to the drivers were voltage amps, but by the time you get to the outputs, they are current amplifiers. Throughout nearly the entire signal path, the signal comes in on the base and goes out the collector. In the output stage it comes in on the base and goes out the emitter.

Aren’t emitter followers current amps by definition? I know they are unity gain. (Now I gotta go look it up.)


It's really no different from an AC power circuit or a 70V line. A certain voltage is available and each connected device draws some current. For example, on a 120VAC power line, a certain current is available, perhaps 15A. We can keep adding lamps until we reach the 15A limit.

The difference between a lamp circuit and our speaker circuit is that the lamp circuit operates at a constant voltage and our amplifier's output voltage varies with the Volume control setting and the musical content.

In our speaker circuit there are two limits -- the maximum current the amplifier can deliver and the maximum voltage that the speakers can handle. In a lamp circuit we can dim a lamp (operate at a lower voltage than the lamp is rated), but if we supply a higher voltage than the lamp rating, the lamp dies.

I have repaired a ton of speakers, and I am not sure that many have been damaged by voltage, but I think most of them have been damaged by heat, judging by the look of the voice coil. Perhaps it is a byproduct of the voltage of which you mention, but it could just as easily be a byproduct of the current flowing.

Part of the problem is the math that we use for our speaker circuits. If we used the same math approach for AC power circuits, we'd be struggling to figure out how many 144 Ohm lamps we could stack on our 1800 watt power line.
There is no truth anymore. Only assertions. The internet world has no interest in truth, only vindication for preconceived assumptions.
Post 18 made on Thursday January 21, 2021 at 03:30
buzz
Super Member
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In my discussion “amplifier” is a ‘box’ that accepts a small signal and it’s output drives a speaker. It really doesn’t matter what is inside the ‘box’.

If one applies a voltage to a speaker, current will flow. If the voltage is high enough too much current will flow and the speaker will cook.

Last edited by buzz on January 21, 2021 04:01.
Post 19 made on Thursday January 21, 2021 at 13:43
Ernie Gilman
Yes, That Ernie!
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On January 21, 2021 at 03:30, buzz said...
In my discussion “amplifier” is a ‘box’ that accepts a small signal and it’s output drives a speaker. It really doesn’t matter what is inside the ‘box’.

As long as the circuit inside the box is perfect, that's true. The perfect box WILL deliver the same voltage at any current. Those are the amps that output 50 watts into 8 ohms and 100 watts into 4 ohms. Many many amps won't output double the power into 4 ohms that they do into 8 ohms.

If one applies a voltage to a speaker, current will flow. If the voltage is high enough too much current will flow and the speaker will cook.

Again, this is true of a perfect amplifier. Not all amps will do this.

But what about OP's original question, anyway?
By the way, OP should use those speakers and that amp. It will work. He should never turn the volume up far enough to make the amplifier clip. He should think about (and then experiment with) the speakers in the environment he wants to use them in (outdoors) to be sure that they output enough sound to play loudly enough.
A good answer is easier with a clear question giving the make and model of everything.
"The biggest problem in communication is the illusion that it has taken place." -- G. “Bernie” Shaw
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