> "Dave King"
> >I am trying to understand the practical implications of the differnece
> > in current flow between a SE vs. BTL amp.
> > First I take a length single wire and fold it over in half flat upon
> > itself so the two fly leads are at one end.
> > Then I connect the leads across the output of a earth referenced SE
> > amp and apply a sinewave to its input. The current now opposes in the
> > adjacent conductors and magnetic flux tends to cancel.
> ** OK, so far.
> > The cancellation obviously reaches its highest intensity at the peak of
> > the waveform.
> ** The magnetic field cancellation effect is not related to the actual
> current level.
> > So ... does the same effect occur if I were to use a BTL amp instead?
> ** Got nothing to do with the source of current either.
> > In this case the current flow is bidirectional (push/pull) per single
> > cycle, not one way.
> ** Absolute bollocks.
> There is nothing so different about a BTL amp.
> A good way to imagine how a BTL output stage operates is to imagine the load
> is made up of two identical loads in series - each with exactly half the
> resistance of the actual load.
> Then note that there are equal and opposite polarity voltages at the ends of
> that split load at ALL points in time.
> Hence, the voltage at the middle point of the split load is ALWAYS ZERO
> !!
> So, it will make NO difference if that middle point is connected to common
> or ground.
> So a BTL stage is essentially the same as TWO amplifiers driving TWO loads
> grounded at one end - but the load resistance seen by each amplifier is *
> half * the resistance of the bridge connected load.
> ..... Phil
What's BTL? I'm assuming that SE is single ended.
