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Why do amp A-B switch-boxes have a watt rating?

Okay, I know that it's not the best thing in the world to have anything besides high quality speaker cable in between my amp and speakers, but my work as an audio engineer necessitates me having multiple pairs of different speakers at the ready.

Why do the A-B boxes that I see being sold have ratings such as "can handle sources up to 100 watts"? If they are just passive switches, what is the rating all about? Isn't it just making and breaking a connection - sort of like touching speaker wire to binding posts? In that case I would think that there should be no limit to the amount of watts that can pass through. Speaker cable for instance carries no such limit. Incidentally my amp is an Odyssey Stratos at 100wpc.
studioray
joeylawn36111
574 posts
 
Probably how much current the internal wiring can handle. 100 Watts into 8 Ohms = about 3.5 Amps of current. The bigger the wire, the more current it can carry.
kr4's avatar
kr4
3,655 posts
 
"The bigger the wire, the more current it can carry."

Right. The same can be said for the switch contacts.

Kal
studioray OP
42 posts
 
Thank you Joeylawn & Kr4, I would have to guess that with my 150wpc amp, that since I'm never really blasting the music, that there is probably no real problem since I probably am not putting out over 100 watts at any time.

But then my next question is this: If a certain switch box is then rated at only 100 watts because it basically has thin wire/contacts/circuitboard on the inside, what happens if you then have a 300 watt amp that you are driving very loudly through it?
phd
1,283 posts
 
Studioray, your Odyssey Stratos is rated at 150 watts per channel into 8 ohms. It is usually better not to exceed the power limits of the switch/box otherwise you can damage (burn up) the box's switches. You could probably get by with the 100 watt box as long as you don't demand too much power.
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