I ordered one of these http://www.ebay.de/itm/TDA7498-100W-100W-Class-D-Amplifier-Board-DC20V-to-DC36V-/201097084382?pt=DE_Elektronik_Computer_TV_Video_Elektronik_Verst%C3%A4rker&hash=item2ed251fdde cheap tda7498 modules, who have an output lc filter. Is it necessary to twist the speaker cables (edit: the cable to the passive subwoofer is 0.75, 40cm long, the one from the subwoofer to the 2 satellites 0.75mm, 4m long) in order to prevent the cables from acting as an antenna? Is it possible with flexible copper cable?
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I wouldn't bother twisting cables.
After the filter the carrier (if any left) will be a sine wave and so very narrow band.
The carrier before the filter is wide band due to being square waves.
After the filter the carrier (if any left) will be a sine wave and so very narrow band.
The carrier before the filter is wide band due to being square waves.
All multi-conductor, unshielded cables should be twisted. By they power, speaker, interconnect or control, it doesn't matter. But you don't need to overdo it. Small cables maybe 1 twist per inch, large cables 1 twist every 4 inches.
All cables can be interference antennas, sometimes receiving and sometimes transmitting.
Also don't expect miracles, this is a problem preventer not a solution to other problems.
All cables can be interference antennas, sometimes receiving and sometimes transmitting.
Also don't expect miracles, this is a problem preventer not a solution to other problems.
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Thanks for the hints (still waiting for the arrival of the ampli-module) would it be sufficient to twist the cable from the amplifier to the passive subwoofer? Would the waves then allready be eliminated? Because I have to dismantle the subwoofer to twist the internal subwoofer cables as well plus the 4m cables to the satellites.
nigelwright75578 said that there is no need, because it's a sinus wave after the filter.
nigelwright75578 said that there is no need, because it's a sinus wave after the filter.
I know nothing about class d amps, but I always wondered why speaker wires are not shielded...we take care of shielding to preamps, and amp inputs, but the amp output is the input for the feedback in a way, so it makes no sense to me to ignore it, especially when highly efficient speakers require very little signal, often smaller than cd players output...so whatever signal those long speaker wires pick up, it goes right back to the feedback loop of the amp.
I am no expert, just thinking out loud.
I am no expert, just thinking out loud.
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