Stringreen wrote:Exactly.....I really don't understand how an amplifier can do its job, yet, I have a stereo amp that I gladly use almost every day.
You may not know how an amplifier works, but you do understand what it does (it amplifies line level signals up to a higher level with the ability to drive 8 Ohm speakers) and basic specs about it (power, distortion, frequency response etc.). These are easily understood by any of us novices.
When I looked at the SRs available on Amazon (and other places), they all looked basically the same and something just didn't seem right to me. I bought one and they are easily understood. They use a NE555 timer IC to generate a 7.5Hz square wave that is amplified up to 5VPP by a single transistor and is fed to a long spiral trace on the board. The spiral trace that some surmised was an antenna is really just a wire wound resistor of 6.8 Ohms. The peak power is ~3.5W.
The spiral trace is what really had me scratching my head. While it might act like an antenna at a high enough frequency, I had some serious doubts that it could be an effective antenna at 7.5Hz. A little math proved I was right. An effective antenna is one that is 1/4 wavelength or some multiple of that. Wavelength=C/F where C is the speed of electricity (186,000 miles/second) and F is frequency (7.5Hz). So a quarter wave antenna would need to be ~6000 miles long. There are 51 loops of PCB trace with an average diameter of 1.5" so the length of the conductor on the PCB is ~20 feet so it needs to be 1.5 million times longer. I measured it with an Ohmmeter and it was just under 7 Ohms. I also have an LCR meter and it measures ~80µH, very low. It would require a 40 Farad capacitor to resonate at 7.5Hz. Judging from the size of the "supercaps" used in car stereo installations (1-2 F) a 40F cap would be about the size of a trash can.
What you have is a low frequency digital noise generator.
Before anyone asks, I did put it in my listening room and I could not hear any difference.