[Elecraft] Amp comparisons

[K9MA]

On 7/23/2018 21:37, Gary K9GS wrote:
> Any side by side with the KPA1500 and the Flex Power Genius yet?
>
I haven't seen any yet. I did have a conversation last year with 4O3A, 
designer of the Power Genius. From what Ranko said, the Flex amp seemed 
to have more headroom than the KPA1500, which might result in better 
linearity at 1.5 kW, albeit at the expense of efficiency. (The specs say 
"capable of 2 kW.") There is some scheme to dynamically adjust the 
supply voltage for higher efficiency at lower power, I presume for CW 
and RTTY, where linearity isn't a big issue. I read somewhere that 
supply voltage is NOT modulated in SSB mode, which I imagine would cause 
lots of nonlinearity.  The Flex amp can do predistortion with their 
radios. However, the KPA1500 also has an output sampling port, which 
should allow it to do predistortion also with a radio capable of it, 
probably including the Flex. (I wouldn't be surprised if Elecraft came 
out with that feature eventually. Could that be the reason it has that 
sampling port?)

The Flex amp has an external ATU, which 4O3A strongly favors, but I 
think that's a personal preference. For most stations, with antennas 
that aren't always below 1.5:1, a solid state amplifier without an ATU 
is pretty useless, so I think Elecraft's decision to integrate it makes 
sense.

While the Flex amp can certainly be made to work with Elecraft radios, 
the seamless integration with the KPA1500 is very attractive. I'm happy 
with mine so far.

73,

Scott K9MA

-- 
Scott  K9MA

k9ma at sdellington.us