[Elecraft] KPA500 vs. other amps

[Jim Brown]

On 6/21/2011 5:51 AM, Ian Kahn wrote:
>   Why should I buy
> the KPA500 when I can get higher-powered (although, admittedly, not much
> higher powered) solid state amps for about 2/3 the cost of a KPA500?

I don't pretend to be an expert on all of the power amps available. But 
there's far more to buying power amp than watts.  We're buying 
reliability, operational convenience/features, technical specs (low 
intermod and harmonics), and a physical package that fits into the space 
on our operating desk and on an airplane for a DX trip.

Last fall I had the negative thrill of using an el-cheapo amp during 
CQWW at PJ4. (Two larger el-cheapo amps had been fried by a previous 
user. One had been dragged back to the factory (in MS) and repaired, but 
the second one wasn't known to have been fried until we fired it up, and 
we didn't have the parts to repair it).  Although rated for 500 watts, 
the little amp fell back to 300W when presented with moderately 
mismatched antennas.  A few months ago, I had a pre-production beta 
KPA500 for a major RTTY contest, with orders to run it with all the 
lights lit.  When my antennas presented it with a 2:1 SWR, it fell back 
from 600 W to 500W.

I installed my new KPA500 the same way the Elecraft engineer installed 
the loaner for that RTTY contest -- coax in and out and PTT.  The first 
sniff of RF drive causes the amp to set itself to the right band, and 
I'm rolling.  If I'm working CW, I simply hit a dit after I've switched, 
and it's there.  This is also the way that later generation Alpha amps 
work, except that they're also doing antenna tuning. :)  I'll buy the 
Elecraft tuner when it's available. And having looking inside those 
el-cheapos and the KPA500, I think cost comparisons with Alpha and Acom 
are far more appropriate.

73, Jim K9YC