So rather than the data or clock causing the issue, it may be the current draw.īut you need to be make sure they don't share a common ground wire with the output signal or power supply. ![]() I've been told disconnecting the 8ft one, or the board attached to that module with most of the leds on it makes the noise go away. One is around 6in long, the other is around 8ft long. The LEDs are driven by a couple of TLC5947 LED drivers on individual modules which are chained to the main board using a couple of 6 conductor ribbon cables. You haven't said how the LEDs are connected The sound goes away if you disconnect the ribbon cable going to the LED modules. The buzzing is presumably the PWM signal to the LEDs. So I don't know what I should actually be doing here. And their schematic seems to show an op amp whereas my output is from a dac. ![]() So if I connect a 5-20 ohm resistor between the Mighty ground and the ground pin on my RCA output.īut looking at my own schematic again, the ground pin on the line out goes directly to device ground. It appears though that Rgbk is actually connected between the ground of the device and the ground of the RCA output. Now that I look at the "Ground Loop Noise Reduction at an Output" section again though, that doesn't seem to match the schematic I got from the other site. I didn't have any 5 ohm resistors, so I tried the 100 ohm which I assume should work but might act as a filter for some of the signal I want to keep, but that didn't make a dent in the noise. And I found some suggestions elsewhere that a 10-100 ohm resistor there would work. and it seems to indicate that a 5 ohm resistor on the ground of the RCA cable should do the job. I found this document by TI with circuits for breaking ground loops: ti.com sloa143.pdf But I don't have a clue how to break said ground loop. These all seem like good suggestions for isolating noise from the circuit, but even if I succeed in removing the noise by adding shielding, seeing as the Mighty and Amp work fine together when they don't share the same power source, correcting the issue with more shielding somehow doesn't really seem like it's getting down to the root of the problem, which the evidence seems to be indicating is the result of a ground loop. Work backward from the speakers to inputs(audio and power). ![]() I'm aware I'm supposed to only ground the shield on one side, but I don't see how I can accomplish that with a standard RCA cable. How? Use shielded RCA cable? I've taken apart two RCA cables and only one had any kind of a braided shield, and that also functioned as the ground connection. Try it without the charger in the circuit.Ĭharger isn't in the circuit except when charging. But I'll make sure it's set up that way for future tests. Pull the Y cable out and plug your 'line out' cable directly into each side of your power amplifier input individually to isolate.
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