Heathkit HA-10 Warrior

[1iwilly]

i have a chance to buy this amp=Heathkit HA-10 Warrior 1kW I know it's from the 70s but in good condition is it a clean amp or splatter box even if you don't over-drive it ?? Compared to my Palomar 300A It's already modified to use with today's modern radios the guy said

 

[Captain Kilowatt]

It is rated at 1KW INPUT. It uses four 811A tubes so you have to be careful you do not exceed their ratings. It is clean if not over driven. As for power out, consider it almost as good as the Ameritron AL-811A. I say "almost" because the Ameritron has a better power supply in it. You should see a comfortable 600 watts pep out of it. It will make 800 if you push it and have lots of airflow and don't mind buying new tubes. Forget carrier modes like AM/FM unless you cut the drive to make no more than about a 100 watt carrier.

 

[linearone]

ive seen 1kw out but it is VERY hard on the tubes. It also weighs more than my mother in law. Its a huge case. I hated mine.

reliable box though.

 

[nomadradio]

1kW peak INPUT power equals 500 Watts average input power. The FCC defined amateur power levels as "input" power back then. When those rules were written in 1934, Joe Ham could afford a meter for DC plate current, and he knew what the final's high voltage should be. Plate current times HV equals input power. In 1934 a RF wattmeter was an exotic lab instrument that cost better part of a working man's annual salary. Took almost 50 years for RF wattmeter technology to get cheap and widespread enough for the FCC to redefine amateur power levels as actual RF power.

RF output is typically about 2/3 of "input", the DC power you draw from the high voltage supply. When sideband took over the FCC declared that the ratio of peak power to average was two-to-one. Hence an amplifier with 1000 Watts average input power would show a peak input power twice the 1000 Watt average. This is why the Drake and Heath 3-500Z-by-two amplifiers were offered as "2kW". A peak (PEP) to average ratio of two to one was the standard assumption back then. Even so, I have seen exactly one linear in my life with a peak-reading plate-current meter. That feature just never did catch on.

But back the the four 811As. If you got that two-thirds of 500 Watts average power, the PEP won't be any more than twice that much, or around 600 Watts PEP.

The plate of the 811A is exquisitely sensitive to overload and permanent damage. Either get used to running at half throttle or watch those tube plates like a hawk.

The 811A was leading-edge tech in the 1930s. So was a flat-head V8.

73

 

[linearone]

The 811A was leading-edge tech in the 1930s. So was a flat-head V8.

73

Couldn't have said it better myself. I know why ameritron still built with them. From a commercial perspective its a familiar part, its still produced, and somewhat affordable. It also has a pile of other issues like huge long wires inside of it that you need to engineer yourself around.
A week doesnt go by that a person emails me asking if i could build them a 4 tube 572b for a driver etc... I could, but I can honestly build a 3-500z cheaper and give them more power for their dollar.

In the homebrew world, which all cb amps are, you get to choose from a wider range of tubes though that often make more sense. i was initially opposed to the russian tube invasion 20 years ago but now having played with them , they are great. Even if the prices went up.

 

[nomadradio]

Back when I would build for hire, I would get asked "how much for four of this tube, or six of that tube?"

My answer was that if you want more than two tubes, you need bigger tubes. The max that makes sense to me is two tubes. Just decide how big you want to be, and two tubes that size will be the best bang for your buck.

Using lots of small tubes made sense only when they were cheap. Watts per dollar cost was lower for six-dollar 6LQ6 tubes, compared to a real transmitting tube.

And 1990s ceramic-tube amplifiers were built with cheap plentiful government-surplus stocks. Four or more 4CX250 types made sense when they were under thirty bucks each.

Those days are gone forever.

And the relative cost of Watts per dollar favors using fewer tubes.

73