amplification: how?
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  1. #1
    Tech Guru sj03w4t's Avatar
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    Default amplification: how?

    I've found some loudspeakers in the attic, and they have RCA cables to connect to the audio source (these type). They don't have any other connection to them nor any power cables. I've tried plugging them into the laptop headphone outputs with these but the sound is very low even if the laptop's on high volume levels.. Is there a way to boost the volume a little? They probably came with some sort of stereo set or something which is probably long gone

    Edit: oh yeah, they are '4 ohm' (sticker on the back)

  2. #2

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    An RCA connection is basically a two-node connector. It's the same as the standard RED (+) and BLACK (-) connectors you see on the back of speakers. They use to use RCA to simplify the speaker to amplifier connection process. (No stripping no polarity confusion). The RCA center pin "The Penis" is (+) and outside "The Flower" is (-). But you won't get any kind of real "POWER" from a PC or iPod output. These are only putting out milliwatts. A real amplifier puts out watts.

  3. #3
    Tech Guru sj03w4t's Avatar
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    Okay thanks. So if I strip off the RCA ends, it will be ordinary speaker wire? So I can then attach it to another amplifier?
    I read that the ohm reading on the back of the speaker must match the ohm amount on the amplifier. How bad is it if the amplifier reads 8 ohms and I connect these speakers to it?

  4. #4

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    You'll need to hook the speakers to an amp. Depending on how big they are, you could get away with using a cheap headunit from a car stereo system.

    As for ohm rating, that all depends. Amps are usually rated to output different power levels at different ohm ratings. Usually, you don't want to drop below 4ohms per channel, but some amps can handle lower.

    As for the amp having to match the speakers exactly, thats not true, amps can usually cope with a range of ohm levels, but you just don't want it to drop too low.
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  5. #5

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    If the amp is not your dad's prized possession and it's not expensive, hook it up and don't crank it to 11. If you smell burning or it's getting really really really hot then turn it off.

  6. #6
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    Basically the rule is, if its good for 2 ohms, it will be good for anything over that. As ohms go up, the wattage capability of the amp generally drops.

  7. #7
    Tech Mentor Villinus's Avatar
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    Get a cheap reciever from a second hand store. Strip the ends of an RCA off to make standard red/black speaker wire and hook it up. Remember, under-amplification is more detrimental than over amplification 9 times out of 10

  8. #8
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    False

    There is no such thing as underpowering your speakers. If the amp is stable for the load at which the speaker is required (4 ohms) in this case.

    There are only two types of speaker damage: mechanical, and thermal, both of which are caused by overpowering your speakers. 100% clipping is acceptable for speaker use as long as the power over time is under that of the speakers rating.

    But you will probably toast your amp.

  9. #9
    Tech Guru Fyoog's Avatar
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    Correct me if I'm wrong as I'm not an expert but I was always taught that as long as you can divide the ohms on the speaker by the ohms on the amp into whole numbers (so like the example above 8 ohms on amp divided by 4 ohms on the speakers = 2) then this will give you the best sound?
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