mp3car

Someone may have already tried to take some measurements, but I felt like doing a little "research" into the grounding mod.

I recently tested the noise level in between the ground terminal on the battery and the block (actually one of the heads, not the block). I tried using my multi-meter (tektronix TX1) and b/c of the constant spikes and other spurious frequencies, I used my scope to do it (TDS 1002, digital). It looks like, hooking up a ground wire between the battery and tha one head dropped the average of a lot of the spikes by about 100-150mv. As I said, I was measuring between the battery terminal and the head that I hooked up the ground wire too. I want to do some more testing, such as between the block and the body, body and battery terminal, and all the other things that could be slightly different. I was always skeptical of this "mod" being an electrical engineer, I found it hard to beleive an additional wire, would help considering there are already quite a bit of 6g/8g wires between the body and the battery, and the body and the block, etc. But, as soon as I hooked up a 4g wire between the head and the battery, I saw the noise level instantly drop by about 100mv, I was suprised it made anywhere near that much difference.

Also, I tried the same thing with a 1F cap. I hooked up the cap with the ground terminal to the block, and then the positive to the battery (pos), and this also caused the noise levels between the block and the negative terminal drop. btw, i have a 92 Maxima SE not a Z, but I imagine a lot of cars would show the same results, with some cars being worse, and maybe some better. There could be some other factors, such as the scope probe picking up noise, but at first look, it does look like it can help "smooth out" the groud planes to make them closer to the same level.

Different ground planes come in to play with audio systems a lot, a lot of you who have bought high-end patch cables for between the head unit and amps, the cable may have had a shield overbraid wire at one end that came out for you to ground at the source. This is to prevent incase the ground planes at the amp and the headunit are slightly different, it would prevent current from being conducted through the shield overbraid. The best thing is to use balanced outputs/inputs for audio systems, that way the same noise effects both the + and the - wire the same, and when they get "subtracted" the noise cancels since both wires have the same noise. (a true balanced signal means, one wire goes "up" and one wire goes "down" instead of just one wire going up relative to a ground plane, so any noise that gets injected on the signal, normally will be the same magnitude and "direction" on both wires, so when they get 'subtracted', it cancels the noise)

When I do more testing, I will take some captures of the scope and post them, before/after using additional grounding wires...

insaneamine

iTrader: (1)

Excellent R&D. I'd be very interested in seeing those scopes.