HV Rectifiers

[WA2ROC]

I have a "modified" Heath Warrior that has several upgraded HV supply components installed.  Someone asked me what HV rectifiers are used and I drew a blank.

They are solid state and were sold under the name that matched the designers call sign.  They are not made any more.  I'd rather not wrestle the Warrior off the desk just to get the name.

Anybody got some clues?

Thanks.

Also, I used the Warrior on AM last night.  Well, sorta AM, that is.  Drove it with my Marauder with it's LSB (and injected carrier at about 40 watts out into the Warrior, set to about 300 watts input.  My watt meter read about 250 watts out and no abnormal heating or plate redness were noticed. 

One operator I spoke with said it "sounded funny" until he tuned off frequency about a KC and it sounded pretty good. 

[KD6VXI]

K2AW (SK)  Silicon Alley comes to MIND.

--Shane
KD6VXI

[w1vtp]

300 watts output carrier power is too much for the 4 x 811a's that are in that amp.  They won't last very long with that kind of service.

I have an EFJ Courier that uses 2 x 811a's and I finally settled on 50 watts output carrier.  Didn't eat up the 811a's at that power level.  The second thing to consider is even at a lowly 100% modulation @ 300 watts carrier you are looking at 1200 watts PEP.

OH - Are we talking input power or output power?  If input power the manual rates the amp at 400 watts - which I disagree with.  Have you looked at the output on a scope?

'nuf rambling for now, GL, Al

[w1vtp]

OK, I'm back.  Here's an excellent piece that I clipped from Janis, AB2RA ( https://www.qrz.com/ab2ra ) who has an excellent technical background.

http://wireless-girl.com/Projects/HeathkitWarriorTR/

"...If you absolutely insist, here are the plate currents to run after tuning up as normal for SSB. Note that this is only true for a set of lab matched tubes. I have a tube tester and a test jig to properly match them. Reduce exciter drive to obtain the following values:

•  AM: Manual says use 265 mA plate current for carrier no modulation conditions. USE NO MORE THAN 200 mA plate current carrier. (Peaks will go to 660 mA on modulation, but meter will not respond quick enough to show them.) To be more conservative, run them at 165 mA and watch the plate color. Stop if any one of the tubes shows any blush. This can happen due to tube mismatch. This is contrary to the 400 Watts (500 controlled carrier) INPUT printed in the manual. This is 320 watts carrier INPUT for an OUTPUT of 192 Watts at 60% efficiency with 1600 Volts, which is what you are likely to get on modern AC line voltages. 320 Watts minus 200 out is 120 Watts total plate dissipation for four tubes. CCS service says plate dissipation PER TUBE is 45 watts. IF THE LOAD IS EQUALLY SHARED, that means you could do four times 45 or 180 watts for four tubes under ideal conditions. Most amp manufacturers spec their amps for ICAS of 65 watts per tube or 260 watts total plate dissipation. But AM and RTTY is NOT AN INTERMITTENT MODE, so don't use INTERMITTENT ratings for CONTINUOUS key down modes or you will pay the consequences. For an exciter with roughly 15 watts carrier like a DX40, this is a useful power gain. For an Apache, it is just plain nuts to use a Warrior amplifier after you detune it or install an input attenuator. The Apache will deliver 100 Watts OUT on its own. The power gain is not sufficient to justify lighting up the 811As. It will be less than one S unit. ..."

Take the time to read the whole article.  It's good reading

Al

[DMOD]

I thought you sounded pretty good Dick, albeit somewhat like an Apache. Band conditions weren't that all good.

It appears that tubedepot has these replacements:

https://tubedepot.com/products/solid-state-rectifier

but one would still have to place series resistors in the leads to tame the HV and LV supplies.

Phil - AC0OB

[WA2ROC]

Thanks for all the comments and warnings.  I just wanted to see if the Warrior could work with the Marauder on AM, and it does, sort of.  I guess I'll stick with my Apache or Viking II and maybe raise my loop up several feet for a better signal.

Oh, thanks for the info on the diodes, Shane.  They are indeed K2AW diodes and will be spared from overload in the future.

[N2DTS]

In the old days we used to abuse 811a's all the time, they were $.25 at fests and WA3JVJ said he would never pay more then a quarter for one, and had boat loads of them.
They took abuse quite well, if you do not melt the plates, they should be ok.
572b's are an upgrade in dissipation.
I have some good ones with partly melted plates, some Russian ones that seem to work ok, and some non A 811's, and some 812A,s.
I always ran them as modulators at 1500 volts and no bias, no color on the plates, but I do not play music.

About 80 or 85 watts carrier is all I would expect, and would worry about the power supply more then the tubes. If the tubes are not showing color, they are happy, but the rest of the amp may not be.
SSB is a very low duty cycle mode and its easy to get gobs of peak power out of wimpy tubes.

I could get 3kw out of a quad of 813's, and 150 watts carrier as an AM amp.