[Elecraft] Elecraft KPA500 vs Tokyo Hy-Power 1.1Kfx

[Ron D'Eau Claire]

Things such as the input capacitance of the devices plays a huge role in the
design too. As a general rule, more capacitance is an issue as one goes up
in frequency. Twice as many devices means twice the input capacitance. 

And then there's the issue of ensuring equal power sharing between the
devices. Doubling the number of devices more than doubles the circuit
complexity. 

I played no part in the design of the KPA500 so I'll leave it there without
speculating on the design choices made. 

73, Ron AC7AC

-----Original Message-----
I think I was not clear and am possibly being misunderstood.  First, I own a
KPA500 and couldn't be happier.  Second, in no way am I saying there is
anything wrong with the KPA500 design.  The question was if the power levels
are the same and the individual device capabilities are similar, why would
one use 2 or 4 devices.  I merely reported what one experienced designer
told me would cause him to use
4 devices.  Was he right or wrong?  Probably neither.  As I indicated he was
used to designing for a different market with a different cost/reliability
model.  If you are cost driven you will run closer to device maximums.  If
you wish to go for long life and a lower chance of failure you derate
devices.



David K0LUM