King Conversions
The KING of 6 Meter Amplifiers
History of King Conversions
If you were able to get through the history of “QROKING” it’s time we talk about how “KING
CONVERSIONS” came about. As you now know I was an avid DX’er and amplifier builder. By this time I
have worked every DXCC country with the exception of 2. Of course P5 and the other is VU4. To this
day these 2 remain the “only” ones I need. Since neither one of them are frequently visited my “on the
air” time is practically nil. I am not much of an “on the air” rag chewer, but God forgive you if you get
me in person or on the telephone! Those of you that know me from Dayton, know that I have a special
seat with all the amenities for a good long rag chew. Ok, so what about KING CONVERSIONS? Well
with all but the impossible DX contacts to make completed, and building a seriously powerful HF
amplifier (remember the Monster Amp?) I needed another challenge in my ham radio career. It’s been
over 12 years now and it is a little foggy just what the initial incentive was to the onset of KING
CONVERSIONS, but I do recall it had something to do with my good friend K2ZZ, George owner of
Radio Oasis. It seems that about 12 years ago he got interested in working VHF and frequently
entering in the VHF contests. He operated 6. 2, 220, 432 in the contests. He did pretty well as he did
have a tower with all the right antennas for the bands. On 2, 220, and 432 he used “brick amplifiers”,
it seems that whatever contacts “could” be made he could make them with enough power from the
bricks. The problem lie on 6 meters, though he did have a brick amp on 6 meters for about 300 watts,
it seemed that it was not quite enough to be really competitive for the tough grids. Taking an interest
in George’s problem with a lack of power on 6 meters, we both searched out what could be done to
increase his power over the 300 watt mark. Any commercially build 6 meter amp (there isn’t that
many) would be out of the price range. At the time, it seemed you would have to spend close to
$3000.00 for a high power 6 meter amp. Hey, that’s about $2.00 a watt for a legal limit amplifier for a
single band!!! A well known friend of ours from our Packetcluster days emerged in our quest for more
power on 6 meters. Our buddy WB2PAG pioneered taking an SB-220 amplifier and eliminating 10
meters and adding 6 meters in it’s place. We contacted him and he “snail mailed” us a step by step
procedure to do this “alteration” to the SB-220. K2ZZ having a spare SB-220 amp that was replaced
with an Al-1500 some years ago, agreed to put his SB-220 up for the alteration according to
WB2PAG. Meticulously following the instructions supplied by WB2PAG we set out to get some higher
power on 6 meters. Taking a better part of an afternoon to do the alterations we painstakingly
completed the task at hand. The next thing to do was to give our work a try. We set up the amp with a
6 meter radio and began to load the amp up as we would load any SB-220 amplifier. As soon as the
amp went into the transmit mode the original parasitic suppressors instantly displayed nice
pyrotechnical display! Once the smoke subsided we were left with a lingering smell burnt carbon. That
was a scary thing! The instructions did not tell us that would happen. We sent a packet message to
WB2PAG telling of our failure and we received an alternate design for a parasitic suppressor. Trying
that helped with the pyrotechnical problem, but now we could not get any power out of the amplifier.
Nada, nein. Zippo. Another Packetcluster message to WB2PAG, the response was “How are you
loading the amp up”? We responded with something like, we are loading the amp up just like we would
on 80 meters. His response to that was try turning the dials VERY VERY slow. You see I could load up
an SB-220 on 80 meters in about 20 seconds or less, that is some quick knob spinning. I tried turning
the knobs a lot slower. At last, by turning the knobs “real slowly” we saw a quick peak in some power
output!! Working on that “real slow” knob spinning we were able to fine tune the amp to the point that
we saw about 500 watts output. That was the best we could do, but George was happy with that.
George used the amp like that for a while, but he could not blink an eye while tuning the amp or else
the “sweet spot” would disappear. The tuning of this amplifier was nothing short of “hairy” for lack of a
better term. It certainly was NOT like loading an SB-220 on 80 meters which is usually as smooth as
silk. Furthermore a pair of 3-500 tubes good to 110 MHZ should give you an easy KW output, where
was the rest of the power? Naturally this bothered me VERY much, being the QROKING, 500 watts
from a pair of 3-500’s was unacceptable. By this time the Internet was something I had gotten into and
I got a computer, an AOL account and a dial up modem. Using EVERY search engine I could I
scoured the Internet for information on 6 meter amplifiers. Since the Internet was in its early stages
the wasn’t as much information as there is today. Using the search engines did return a repetitive
amount of data on a single person who apparently was doing conversions on SB-220’s to SINGLE
band 6 meter only units. It seems that this fellow, KM1H, Carl, had been doing this type of thing for
some time and all the reports I was getting indicated he could convert an SB-220 amplifier to 6 meters
only and obtain 1000 watts output!! I e-mailed Carl about some information on just what he did to
obtain this kind of results with an SB-220 conversion. Well it was like pulling teeth on a 100 pound
snapping turtle to get a peep of what needed to be done! Well, I finally found someone who was a
stubborn and determined as I was and I was politely told that old cliché “Does Macy’s tell Gimbles?” I
remember that cliché from when I was quite young, and now I got the full message about what this was
all about. Knowing little more than I did before all of this Internet searching, I knew one thing more,
This “could” be done.

I contacted George and asked if I could tear apart his SB-220 and attempt a single band 6 meter
rebuild. During the off season for 6 meters I took that amplifier and I spent numerous sleepless nights
endless days off from my regular job and painstaking venture for more appropriate parts for the job.
There were numerous failed attempts and the pyrotechnic displays on the parasitic suppressors
seemed unavoidable. Days turned into weeks, weeks turned into months, the obsession consumed
me.

Relentlessly, I was able to overcome one problem at a time. I finally hit on a combination of ideas that
actually worked! There were certain caveats with the early model of conversions I was doing. I would
explain exactly how to avoid them and began doing some conversions for those who really wanted
some extra power on 6 meters. At that point in time about 900 watts was my benchmark. Since many
hams were now sending me SB-220 amps for conversion, I started to also modify the front panels so
the amp identified itself as a 6 meter amp. I also put KING CONVERSIONS on them, it seems from that
day forward I was known as KING CONVERSIONS.

Now that I have been doing these conversions for over 12 years, the evolution has come full circle.
Since I have done HUNDREDS of these conversions, I have also tried different things along the way.
Very small improvements here and there over this period of time, has evolved into a simple SB-220
amplifier being converted to a single band 6 meter amplifier that is capable of LEGAL LIMIT power
output!! Twelve years is a long time dedicated to building and improving the operation of a single
band amplifier. I can finally say that as of about a year ago there is no longer any room for
improvement. It is as good as it is going to get. Being I am my own worse critic, if I can be happy that I
have obtained the “best”, I have to believe it is.