Re: Bias-wise

will = while somewhere in the text, you all understood right ?

"Dr Gang" <adra.aganga@xxxxxxxxx> a écrit dans le message de news:
43c63051$0$18558$626a14ce@xxxxxxxxxxxxxxx
> Hi,
>
> As I've posted a few days ago, I've finished my tube power amp project and
> had only the bias to set.
> Since the bias is some sort of setting of middle point for the tubes,
> considering those have a maximum voltage swing, if the bias is too low,
> there'll be a discontinuity between the positive and negative parts of the
> waves -> low volume and distortion. If the bias is too high, each tube
> will work not only on its half of the wave but also on the most part of
> the other tube's wave -> lowering the global power yield and constant
> dissipation cutting on the tubes' life expectancy.
> If this is correct, then you probably can set the bias only by ear : will
> turning the bias pot, you should start by having no sound at all, then a
> bad quality low sound will come out, increase in volume and quality. You
> should reach, at some point, a maximum volume when the middle point is set
> for exactly each half the wave to be amplified by each tube. Going further
> will bring you into the AB class domain : the middle point goes up, the
> voltage swing capability lowers -> volume lowering and each tube will work
> increasingly on the other tube's half of wave. Going even higher will make
> your amp a pure A class with 2 tubes amplifying exactly the same wave,
> with half the power they could theorically develop.
>
> If this is correct, wouldn't it be enough, to set the bias, to simply turn
> the pot until you reach the maximum volume and then go a notch higher ?
>
> Yeah, i'm lazy !
>


.

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