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Reviews Categories | Amplifiers: RF Power - 6M/VHF/UHF+ | King Conversions 6 meter amps Help

Reviews Summary for King Conversions 6 meter amps
King Conversions 6 meter amps Reviews: 76 Average rating: 5.0/5 MSRP: $(missing—add MSRP)
Description: HF amplifier conversion to 6M
Product is in production.
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N8FVJ Rating: 5/5 Jun 20, 2018 03:12 Send this review to a friend
AL-80B Conversion  Time owned: 0 to 3 months
The AL-80B works great producing 1000 watt PEP out. This amp makes sense for 6 meter conversion due to low capacitance of just one 3-500Z tube vs two 3-500Z tubes in other amps that only produces 200 more watts output. One 3-500Z tube is more efficient on 6 meters.
K9JN Rating: 5/5 May 22, 2018 12:31 Send this review to a friend
Outstanding Conversion  Time owned: 6 to 12 months
Could not be happier with my SB221 King Conversion. It was so simple, took amp to a shipping store, they double boxed it and off it went. Turn around was so quick. Amp looks brand new and is a total 6M Beast. Lou made the amp look brand new and 6M has never been so fun.
N8ERM Rating: 5/5 Jun 4, 2017 14:28 Send this review to a friend
Lou six meter conversions  Time owned: more than 12 months
So get your amp to Lou owner of King Conversions and it will arrive doing exactly what he says. You can take it to the bank.
WB6YIY Rating: 5/5 Feb 16, 2017 16:04 Send this review to a friend
Everything is GREAT  Time owned: 0 to 3 months
Terrific! All works as I was told by Lou,50wDrive=700wOut! If you are in the market for some POWER give Lou a shot.. Very Satisfied.Keep up up the GREAT WORK!!!
N0AN Rating: 5/5 Jan 23, 2017 13:54 Send this review to a friend
First Rate Conversion  Time owned: 0 to 3 months
Product: SB220 Conversion to 6 meters


Outstanding. Knowledgeable. Excellent Communication before the sale. Kept in contact via email during the build, test and shipping phases.

Quality packaging. FEDex did its best to crush the Tube Box, and only Lou's very substantial packing saved the tubes. Amp was super packed! The packaging is "homebrew" but very well done.


This amp was purchased exclusively to run Meteor Scatter on 6 meters using MSK144. MSK144 has a duty cycle (compared to a single tone) of about 60%. I specified to Lou that the amp needed to meet these specs:

RF Out: 600W in MSK144 mode, 15 sec on 15 sec off, Max of 25 minutes total per QSO.

Here is how the amp performs:

Tuned for Maximum Out with a Drive Power of 70 watts from a TS-590SG

CW Tune (Lower Plate Voltage)

Plate Voltage: 2100
Plate Current: 550 ma.
Grid Current: 200 ma.
Output Power: 650W average (not PEP)
Plate Input Power: 1155 W
Efficiency: 650/1155 = 56%
Tube Dissipation: 495 Watts
Available Dissipation: 1000 Watts

The 3-500Z tubes show NO COLOR WHATSOEVER during the 15 second transmit sequence and handle 20+ minutes of sequencing easily. The amp appears to be loafing.

CAVEAT: Do Not Run This Amp for MSK144 in the High Voltage (SSB) Position! The power supply in the SB-220 cannot tolerate this kind of load in digital service. Yes, you can get 900 to 1100 watts out, but you will blow the amp up. (Many have)..there is also a cooling issue at the higher power, high duty cycle operations.

The instructions for tuning up the amp are very clear and ...they work. You get max output for a given level of drive and keep the grid current in range.

For MSK144 mode, tune it up using MSK144, not single tone. This has a major advantage because the duty cycle of MSK tones is much less than a single tone tune-up, and you can't transmit for longer than 15 seconds because that's how standard MSK144 works! Double blessing: lower duty cyle than single tone, and a mandatory 15 sec rest between key down tuning. Even the most lengthy tuning sessions won't tax the amp!


It appears Lou built in a soft keying circuit, so the rig only has to see < 6 VDC on the keying line. This should be safe for any modern radio.


Cooling is an issue for nearly any amp or exciter in digital service, even something as forgiving as MSK144.

After watching the amp run for a few hours, I found a consistent heat flow at the front left top of the case. I laid a small USB powered cooling fan on the front, left, top of the case, exhausting air. This removes quite a bit of hot air, quickly, which can only be good for the amplifier.

I also put that same kind of fan (Amazon), on the TS-590SG driving the amp. It is blowing air from the front of the radio, just underneath the Tuning Dial, toward the back. The radio runs cool now, compared to a half hour of MSK144.


First Rate service
First Rate Performance

What more can one say?

73, N0AN
NK9O Rating: 5/5 Dec 4, 2016 20:31 Send this review to a friend
LK500 Amp Repair  Time owned: more than 12 months
Lou: Helped me initially to repair a QSK board and spent considerable time to walk me through it. I had additonal issues and had to send the amp in. I cannot express the impressive repair work and customer service that I received even after the amp was returned with follow-up e mails.
Bought a LK500 6 meter conversion amp afew years aback also outstanding experience overall.
Try King Conversions and you will not be disappointed.
KA4KOE Rating: 5/5 Sep 7, 2016 18:01 Send this review to a friend
Excellent/Repairs Amps Too!  Time owned: 0 to 3 months
Lou is now repairing some brands of amps. He repaired a QRO HF2500DX that had some issues I simply did not have the time to address. Good communication and extremely fair to deal with.
VK6JX Rating: 5/5 Mar 18, 2016 20:30 Send this review to a friend
Super impressed - full output on 6m with easy tune and load.  Time owned: 3 to 6 months
I wanted to get back into 6m and needed a decent amp. I had an SB220 that Bud KC4DWI gave me many years ago and I wasn't using it. Then my mate Alek VK6APK told me about Lou W1QJ and his King Conversions. I did some research and called Lou. 5 minutes later I was shipping my amp to him.
The 220 arrived back and I was amazed how new it looked ! I fired it up immediately and sure enough, full legal US output. Input tuning was smooth and easy. Input SWR was 1.1:1. The output tune and load were likewise easy to use. Alek and I were amazed at the transformation - and the full output with not a trace of instability.
I feel like when I first got into ham radio at 14 years old, over 40 years ago. Thank you Lou - for the fantastic 6m converted amp - and that feeling !
Best 73 from downunder,
John VK6JX - Perth, Western Australia.
AB1NJ Rating: 5/5 Feb 23, 2016 06:43 Send this review to a friend
PERFECT - A Great Experience   Time owned: 0 to 3 months
I received my AL-1500 from Lou this week, and I am super impressed. This amp is perfect for 6M EME and meteor scatter. It can put out 1500w for digital modes like JT65, FSK441, JTMSK all day without working up a sweat. Lou is simply the best to work with. He answered all my questions and obviously puts his heart into these amps. I can't say enough. Thanks Lou!
KM5SC Rating: 5/5 Jun 19, 2015 11:20 Send this review to a friend
OUTSTANDING  Time owned: 0 to 3 months
Having earned DXCC, I was now interested in VUCC. 6 Meters was the way to go, but my 100 watts was not enough for me. After months of research, I selected King Conversions. Lou, W1QJ, "The King", King Conversions. Over the next month, Lou answered all of my many questions. Lou takes HF amps and converts them for 6 meter use only. He can convert most HF amps, but his preference, and the one he happened to have in stock was a Heathkit SB-220.

Even after placing the order, Lou continued with his Outstanding customer support. Lou explained how I should run a 240 volt line in my house to get the best performance from his amp. New tubes are available if you like, but I selected used Eimac 3-500Z tubes and saved the money to run the 240 volt line.
The tubes were tested on Lou's test bench before shipment.

King Conversions are special ordered and custom made by one man. These are not production run amps. Once my order was placed, it took one month to complete the conversion. To properly ship the amp and tubes, which are shipped in a different packages, Lou takes a complete day just to properly package the equipment prior to shipping. Lou cuts stiff foam panels to place on the bottom, sides and top of the amp. Any extra space is taken up with the foam "peanuts" he adds to the First box. He then takes box One, and places it inside box Two which also has the custom cut panels on all sides and foam peanuts. He completely seals the box and adds many labels...This side up, Do Not drop, Etc. The tubes are shipped in a different package. Each tube is wrapped in "bubble wrap" and then placed inside a box containing foam peanuts. It took 5 days for the insured shipment to arrive at my house in the Houston, Tx area. There was no damage at all.

The amp and tubes looked Outstanding. Everything looked like NEW. Quality of workmanship was Outstanding. Lou had sent complete detailed instructions for installing the amp. Additional instructions followed on how to properly tune the Converted Amp for maximum performance.

The amp worked in an Outstanding manner. I am extremely pleased with my King Conversions 6 Meter Amp.

If you are serious about working 6 meters with power, I strongly suggest you order a King Conversions Amp.
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