High bias class D

[Pafi]

RF radiation can be magnetic, elektrostatic, induced by common mode, differential, or mixed mode signal. Wich one do you think about?

RF radiation and RF sensitivity of a cable are proportional to each other if the signal (mode, impedance) is the same.

Twisted cable reduces the unwanted coupling of differential mode signals. Common mode voltage is still radiated, and common mode current would be radiated also if it were present.

 

[MusicSeeker]

Maybe a stupid question,but... would twisted speaker cables reduce RF? I mean, twisted signal cables can work without shielding. But maybe that only works "the other way around", prevent signal cables to pick up RF? Just a thought, looking forward to be enlightened

Twisted cable work well on hier frequency signals like 10 MHz and above up to various GHz
They are used in the industry for USB, LVDS, ethernet etc....
But to be efficient, the wave length of the electrical signal has to be much shorter than the equivalent electrical wavelength of the distance between two wire turns. In other words, the frequency much be higher

So in "low" frequencies, the best prevention is a shield, in high frequency, twisted pairs behave very good with cheaper cables than shielded ones.

Also twisted cable work with two electrical signal in phase opposition. One signal see the positive signal while the other cables see the exact same amplitude opposite polarity signal. In audio, it is not the case most of the time as "-" is often the electrical ground. With bridged amps, this condition is satisfied. With this TK2050 amp when used in bridge, it could be done, but no in the sure one I think (got to check schematics, but I think it is not bridged)

cheers

 

[ronte]

Thanks all for the reply! The Sure amp is bridged (TK2050 in bridge mode), would mean twisted speaker cable could be useful if problems with EMI. The switching freq as you say would be mirrored (+ -) in these amps in bridge mode