>
> Hi Todd:
>
> Any time you add another stage, you need to be concerned about
deterioration
> of the signal by a few more db.
Not necessarily.
If the driving power is correct not to overdrive any of the amplifiers
in the chain, an extra stage can be useful to reduce the IMD or even
noise.
The most perfect final stage with plenty of linearity and dynamic can't
do anything else than amplifying the distortion produced by previous
stages while its "contribution" is small.
In most cases of bad signals (wide channel) the guilty is a transceiver
with a bad IMD and not the power amplifier.
Not always, but often, an intermediate amplifier stage between RTX and
PA with a good and effective ALC loop produces a much better signal
than the same transceiver but "pushed" to obtain its max power.
73,
Mauri I4JMY
> The 4-1000 is pretty clean. The 811A can be pretty good. But once
you put
> the additional tubes in the middle, you risk overdriving the 811 tubes
> and/or the 4-1000.
>
> One nice thing about the 4-1000 and a 100 watt rig is that the 4-1000
will
> not flatten out. My experience is that overdrive is the number one
reason
> for splatter. Some amateurs think ALC solves the overdrive problem,
but it
> masks.
>
> At least with the 4-1000 and a 100 watt rig and no ALC, I know that no
> shouting into the mike during an exciting time will cause splatter.
That is
> worth something.
>
> A ham close to me opeates a SB-200 using 572b tubes into a 4-1000
amp. He
> has everything turned up wide open and splatters for very wide range.
> Fortunately, I operate in the same 10 khz window, so I can
rationalize that
> even a good signal would wipe everything out.
>
> 73, Colin K7FM
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