BiBer;396789 Wrote: > > could someone please explain why the sb output drifts from 0V without > load?
The signal coming out of an RCA plug is an AC waveform which swings both positive and negative, and is centered (biased) at zero. In order to produce a signal that can swing both positive and negative, your circuitry needs to have both positive and negative power supplies... That is, unless you offset the signal that you're producing, by adding some bias voltage. You could center it around 4V, for example, and let it move around between 0V - 8V. Then right before the output, if you place a series capacitor, this will remove that 4VDC bias because it will get "soaked up" by the cap. This gives you the desired signal which moves both + and -, without requiring a more complex power supply circuit. The (very small) load on signal is what brings it to zero - or, for that matter, whatever the _amplifier_ considers to be zero. Without this load, the capacitor is just kind of "left hanging there" with nobody telling him what zero is. Gradually it will self-discharge internally - this could take several minutes, and then once that charge is gone, the signal will drift up until it matches the source's bias voltage. -- seanadams ------------------------------------------------------------------------ seanadams's Profile: http://forums.slimdevices.com/member.php?userid=3 View this thread: http://forums.slimdevices.com/showthread.php?t=60122 _______________________________________________ discuss mailing list [email protected] http://lists.slimdevices.com/mailman/listinfo/discuss
