The 572 is capable of putting out more power but to do that you need to
supply it more power!
Remember that this is an amplifier and if you can load it to put out more
power it'll draw more from the power supply.
A little less than half the power will be used up in the plate resistance of
the tube and dissipated as heat and most of the rest can be loaded into the
antenna. Some of the power will be dissipated as heat in the internal
resistance of the power supply.
So if you install 572 and try to load it more, the internal resistance (read
capability of the dc power supply) will be the limiting factor. Power output
is effiency times volts times amps. I'll bet the that Ameritron didn't
leave any reserve in that power supply so you if your that set on it build
an outboard supply and put in the 572 and you'll get more power. A 572 can
take 2400vdc on the plate and 600 watts whereas the 811 is rated for 1700vdc
at 270 watts. The thought sounds good but it's too good to be true so I
agree with the previous response to buy better coax and that'll help on rx
as well. Two other things you should consider is a good used Heathkit SB
200 or better yet Heathkit SB 220 with 3-500Z . Both are very good amps and
very reasonably priced. Drake L7 and L4 are also very good but cost a
little more. If you have to have the power find a good Heathkit and you'll
> Bit off-topic maybe. Has anyone here have any knowledge
> or experience with the following?
> I've heard you can take any of the Ameritron's running the
> 811's and do a direct swap for 572B's. The 600W goes to 800W
> and the 800W goes to 1000W , no other mods needed, no muss,
> no fuss. Sounds nice as I'm considering getting an Ameritron in
> march, but money is an issue. Most Ameritrons are running about
> 1.00 to 1.75 per Watt, so I'd like to know if this is true.
> KG4JBM/ Andrew
> Remove "your.hat" when replying via e-mail