On Sat, May 22, 2010 at 04:27:11PM -0400, Roger wrote:
> On 5/22/2010 1:22 PM, Jim Brown wrote:
> > On Fri, 21 May 2010 19:32:43 -0400, Roger wrote:
> >> The screen is the most sensitive tuning indicator and particularly so at
> >> the higher power settings.
> > So if I watch the screen current, am I tuning for minimum?
> In the final stages of tuning a Tetrode amp you are peaking the screen
> current with the loading control. This peak coincides with maximum
> output, or should and is a sharper peak than the output.
> If the screen current is excessive, back off on the drive a bit and
> retune. The max screen current should also come with minimum grid
> current for any specific drive. IOW, increasing screen current decreases
> grid current.
Never having had a tetrode amp, I feel compelled to ask: Should you
always tune such an amp for a peak reading (within the acceptable
range for screen current) and not add a tad bit of loading for linearity,
as one normally should for a triode amp? (If you're going to add some
load anyway, what is the advantage of having that nice sharp peak?)
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