> >Did I say suppressors? I said most of your mods are basically
> >harmless, but some of your suggested mods are harmful and can
> >ruin tubes.
> >
> the dodge
No, cars have nothing to do with it.
The biggest goof-up is recommending people fuse grids with
resistors, and remove electronic protection. Bad idea.
> >>
> >>I'm disappointed to see anyone tell others a
> >>short absorbs energy.
> >>
> >Ä It doesn't. It slows the flywheel
> >
> >I had no idea a short reduced the output
> >frequency of a PA. I don't think that is correct.
> >
> agreed
> thanks.
> delete "slows " - replace with "reduces amplitude of ".
That's still not true. When the load is removed, even by shorting the
output port, voltages in the tank can increase.
A typical tank, with the output shorted, reflects a high impedance
at the anode. That allows the tube to slip into a low-conduction
angle mode... conducting anode current in bursts. This allows tank
overshoot, and tank voltages increase until something extracts
power from the tank or the tube/power supply combo quits adding
energy to the tank.
That can create a big bang, a burned bandswitch, or a melted air
variable on the tube side of the tank. If you open the load, the
loading cap can fail and things on that side of the tank arc.
Of course line length between the amp and the open or short
affects the type of failure, as well as tank component values do.
The mode of failure depends on phase-shift through the tank and
the type and value of components.
Open or shorted loads, or underloading of the tank, is the single
largest cause of tank component failures.
73, Tom W8JI
w8ji@contesting.com
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