If I have a bass amp (head) and the speaker output says "150 Watts, 4 Ohms", what happens when you plug it into an 8 Ohm speaker. Is this supposed to degrade the sound? Is it bad for either the head or the cabinet? Is there any accessory you can get to match the impedances for you, and if so how important would it be to get one?

Thanks in advance ..

From what I've heard it can damage your poweramp as well as your cabinet. But I'm not 100% sure if that's completely true. Just wait for xDx to come along and he will help you.

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a 4 ohm output into an 8 ohm cab shouldnt damage anything, but it may reduce volume a little and degrade the sound a little.

http://guitargeek.com/chat/showthre...&threadid=46544

this is a good resource

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Has it got a tube driven or an SS poweramp?

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The Ohm question is one that has been explained to me several times, and yet, I can never remember whats ok and whats not. And it gets more confusing when you start using 2 cabinets.

My Peavey 5150 luckily has 3 choices, 16, 8 or 4 Ohms. However, it's other people's cabs that sometimes cause the problems, particularly if they are stereo cabs and aren't labeled very clearly on the back.

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This one is strictly SS.

I read also that if you have tubes in the power amp, you can fuck them up if the amp is on but has no speaker (or "load") connected. Some say that on SS amps, you cannot connect a speaker with a lower impedance rating than the amp, because it will draw more current than the amp was designed to handle. Opinions on these matters are many, and in direct disagreement with one another. (Even in the thread recommended in post #3)

I think if someone here has or knows someone with an Electrical Engineering degree, we might be able to once and for all sort out this mess...

what can you find that disagrees with the info on the link i posted?

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Yea without having any load to the power transformer, it will get fucked up..
Same with having a wrong value load (IN TUBE POWER AMPS), SS poweramps doesn't work the same way.. If it sais 150 watts at 4 ohms, that is the minimum load you shall hook it up to as it is SS, as your speakers resistance (ohms) increases, your poweramp won't be able to put out as many watts as it is rated at 4 ohms

edit: Still I doubt you can have a SS poweramp without any load at all attached to it, so don't try, always have a minimum of a 4 ohm load to your amp

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