So I wanted to add a better set of speakers to the ship's PC for movie night. Simple enough, the PC runs off of native 24V, I bought a 24V - 19.2V DC-DC transformer for the monitor and snipped of the brick and wired it in. Surely if I buy some PC speakers with a brick I can do a similar trick, right? Because down here in the Caribbean choices are limited in terms of what you can get, and I couldn't get anything loud enough that didn't run off of AC power. My hope was to run the speakers directly from battery power without having to fire up the 2400W 110V inverter, that way I could wire them directly to the power panel and dispense with power cords and bricks all over the place.
So I picked out a pair of low profile speakers and checked the power block - 10V nominal voltage. Odd voltage, but I should be able to find something. Sure enough, I can find a variable DC-DC converter from China on E-Bay that will let me convert from 5-32v DC in, to anywhere from 5-32V DC out. $13 with free shipping, what can go wrong?
Until...I looked more closed at the stupid power block for the speakers. It is an AC-AC block, producing 10V AC power (500 milliamp), not DC. WTF? I put a multimeter on it to be sure it is in fact 10V A/C, not DC like any right minded engineer would use.
Attempts to find a small inverter circuit to produce 10V AC power at very low currents (half an amp!) have proven fruitless. I don't need lots of wattage here at all, but I need to figure out how to get this odd voltage from my ship's DC banks without running a 40 pound inverter that wastes more power on it's overhead than I need.
I'd love to see 12V or 24V DC in, 10V AC out. Small and cheap; I already have a big inverter with wall plugs, and the stupid little bricks for charging cell phones and whatnot - what I am looking for is a solution to permanently wire to the boat out of sight to power the speakers like the rest of the PC is powered.