Pure paranoia! :)
I tend to creep into things I consider limits, and not race to them. I
normally run the amp in such a way that it never exceeds 60 or at worst
65 C. Seeing it hit 70 makes me nervous...
So...
Prior to any excursions in to the above 70C area I need to learn more,
which is what your post just helped me do! Thank you!!
Knowing that others can run the KPA500 90C, eases my fear of amp final
damage.
I have always ran tube amps in the past, and at one point owned a very
sensitive SS amp, which killed a few sets of finals.
It turns out there were other issues at play, (design issues I think),
but that experience made me very jumpy about SS amps. I almost went
back to tube amps prior to purchasing the KPA500. After owning KPA500
for a while now, I would never go back to tubes... So I am being as
careful as possible to insure I understand what I am asking the amp to
do, before I ask it to do something it was not designed for.
73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist
ARRL Asst. Director, NW Division, Technical Resources
On 5/3/20 1:36 PM, Jack Brindle wrote:
Dave;
The KPA500 will protect itself above 90C, but it will work quite well at 70C.
Why do you stop at 70C?
73!
Jack, W6FB
On May 3, 2020, at 1:26 PM, Dave Cole <[email protected]> wrote:
Hello,
I just got the new MMSSTV software, and will be running a bit of SSTV. SSTV is
100% duty cycle.
Initial testing here indicates no power level is safe... At 150 watts the
KPA500 reaches 70C pretty fast, in under two minutes, and 70C is my upper limit
for testing... At 500 watts it reaches 70C in about the same time...
Can I assume the amp is not the most efficient thing in the world at 200 watts?
If the KPA500 can't deal with 100% duty cycle, for two minutes, how does the K3
deal with 100 watts for two minutes, at 100% duty cycle?
--
73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist
ARRL Asst. Director, NW Division, Technical Resources
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