Ohm Switch on Home Audio Receiver

[TeenWolf 10+ year member]

My home audio receiver has an ohm switch that can be changed to 4 or 8. What is the purpose of this switch? I understand resistance, but how does this switch change how the amp work? You don't see a switch like this on car audio amps. If the amp is stable at 4 ohms, then why the switch?

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[JimJ 5,000+ posts]

My guess would be to put maximum power into 8 ohms...because if running in the 4 ohm position, it would be running at half power. Why they couldn't engineer it like JL's Slash series amps or the PG Tantrums or Xenons to put out the same amount of power over the impedance range, I don't know. I've never seen an amp with a switch like that before.

 

[Prowler573 5,000+ posts]

My Technics receiver has a weird feature...it's compatible with drivers lower than 8 ohms but if you're going to use any you have to turn the unit off, hold a button down and while doing so, turn it back on. This supposedly puts it in a mode where it will safely run lower impedence drivers. I've never used that option so I don't know specifically what it does...but it's there.

 

[93 saturn sl2 10+ year member]

my yamaha receiver has a switch like that on the back of it.

 

[TeenWolf 10+ year member]

I have a Sony receiver. My speakers are 6 ohms, so I just leave the switch on 8 ohms.