Sony 8ohm 2W Bare Speaker-How to Hook Up to iPhone

angusthedog said:

Hello,

I have a Sony 8 ohm 2 watt bare speaker with no amp (just positive and negative posts). I want to hook this up to a 3.5mm headphone jack for use with my iPhone or MacBook. So far I have cut some super-cheap airline headphones with a jack connector and stripped the ends and tried hooking it up, but nothing happens. I assume this is because I have no amp, but I'm sort of new to this kind of thing.

Any help you can give would be appreciated.

Thanks

Click to expand...

If I remember this correctly, the MacBook Pro's internal audio amp does something around <1W at 8ohms through the headphone jack per channel in stereo mode. However, very thin cables and a 8ohm speaker aren't that great of an idea, maybe upgrade it to 15AWG?

angusthedog said:

Thanks for your help.
I found and RCA-3.5mm cable and I cut and stripped the RCA end and it actually works great with the iPhone or MacBook Pro. It's probably about 16AWG.

Click to expand...

It is no where near as large as 16awg. You do NOT need anything that large. You problem is NOT the wire size.

The problem you are having is caused by several things, the very low power of the Macbook's amplifier which is at most about 0.1 Watt and the very low sensitivity of those speakers (might be as low as maybe 73dB/W at 1 meter) and then the 8 ohm load might be hard to drive and a poor match for the headphone amp in the computer.

You need a line level to 8 Ohm speaker amplifier. Either that or speakers with a built-in amp.

It is possible to damage the Macbook if you don't understand how this works or you are careless. By "understanding" this means you should know how to measure the characteristics of the Mac's built-in amplifier. If you can't explain how you would do that, just leave it alone.

Again the size of the wire in the cable absolutly does not matter. And I bet it is more like #26 than #16 wire. FOr a 100 milliwatt signal going just a few feet any size wire will work, the limiting factor is mechanical strength. You need some minim size just so you can handle it without it breaking, So they typically use #26 or even smaller.