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A friend of mine was asking me to splice a 45-Ohm intercom speaker volume control between his speakers and receiver, at 6 or 8 Ohm.

Obviously it's not ideal, but what would happen? Would the speakers be damaged? Or just be reeeeeeal low?

B. Haut
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  • The amplifier is liable to get damaged. The transformers and output stage are designed for a specific speaker impedance – crasic Nov 29 '15 at 22:43
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    Most likely, really quiet audio, with little sensitivity to the control position. Damage is a theoretic possibility, but probably less likely when running an audio amplifier without a load (or with too high impedance a load, which is what you would have and almost the same thing) than it would be when running an RF amplifier without one. – Chris Stratton Nov 29 '15 at 22:51

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If you wire it just as a variable resistance, the volume will be low until you turn it nearly all the way to low resistance.

By adding high resistance, you reduce the damping the amplifier can provide to the speakers -- this may affect the frequency response (you may get some small amount of peaking at the speaker's natural resonance).

It won't damage your amplifier or speakers -- amplifiers are designed to be able to operate with light or no loads which is what this does.

If it is a high power amplifier (more than a few W), then likely high volume will damage your potentiometer (volume control) by forcing it to dissipate too much power.

jp314
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