Inside: At the heart of the Marpac 980A is a high-efficiency Jakel J238-038-3325 C Frame Motor. Ok, it's just a fan.
That's really all there is to it. If it ever breaks, you can find replacement motors online. These are the same motors used in bathroom exhaust fans. You can find motors like these for under $10 at surplus sites online. So, if you're really cheap you can spend a lot less than $50 and build your own. Of course, it will be ugly and probably cause a fire. . .
The Marpac Sleepmate/Soundscreen 980A is rated "less than 40 watts". I was concerned that this sound machine might use more power than our iBook (which previously served as our sound machine via the nifty Noise utility), so I decided to test the Marpac with a KillaWatt.
On high, 13 watts. This is considerably less than the .33 amps (39 watts) that the motor is rated for. I'm not really sure why this is the case; perhaps because the motor is hardly under any load, having been fitted with such small fan blades? In any case, it'll cost less than $10/year to run 8hrs/day. Probably closer to $2.
Ok, finally, here's a video of the unit in action, at BOTH speeds!
Overall, we're very happy with the noise that the machine produces. Although it is a lot different than the Noise application, I think it is more soothing and has a much larger range of sound, probably due to the fact that the speakers in an iBook can't create any bass to speak of. I am also very sensitive to "sound loops" produced by some electronic noise machines, and of course this machine is completely immune to that. Overall it is a simple, low-tech solution to an old problem, and more elegant than a box fan.