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Reviews For: Mercury IIIS HF/6m amplifier

Category: Amplifiers: RF Power - HF & HF+6M

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Review Summary For : Mercury IIIS HF/6m amplifier
Reviews: 71MSRP: $2500/kit $2800/assembled
This solid state HF amplifier uses a single LDMOS for
fully automatic operation from 160m to 6M making 1200W with
input power between 50 and 90W depending on your ALC
setting. Protected against antenna SWR over 2 to 1 and
also against excessive input power. Builtin power supply
for 120 or 240 VAC without changing taps in the
transformer, just changing the power cable plug.
Fans work silent and color front panel display. Output to
three antennas selectable in the display with operator
Available as either a kit or starting in early 2022 factory assembled.
Product is in production
More Info:
# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
AD5VM Rating: 2022-07-25
Another happy customer Time Owned: 0 to 3 months.
If you can handle the current 8-12 month wait and can handle an easy four hour build, you'll end up with what feels like a $5000 amp for $2500. Same size as my 7610 so it looks great. I get 1200 watts SSB with about 40 watts drive - while plugged into a 110V outlet! I'm running 33 watts drive to get an even kW which is all I wanted. Auto band-switching works great and happens during the first syllable of the first word. I can barely hear the fans, even if you set them to max, they are still very quiet. I also have one of Kenny's ATU's. I suppose I'll keep using the 7610 until he makes a transceiver. The American Dream is alive and well at KM3KM. I would love to learn more about his backstory. Kenny & Angel, if you're reading this, please put my name on the wait-list for whatever you sell in the future and just shoot me the Paypal invoice when it's time to pay for whatever it is.
KC1AW Rating: 2022-07-16
Great solid state linear amplifier Time Owned: 0 to 3 months.
Great Amp. East to use and setup. Great reports from contacts. A+ ..
AD0AR Rating: 2022-07-16
All around excellent amp for 120-240V! Time Owned: 6 to 12 months.
I chose this amplifier after trying to build a problematic EB104 kit.
I learned many ins and outs of building an amplifier on that mistake of that eb104 purchase and was looking for a better performing cost effective kit.
Since the Mercury III amplifier had all the features that I wanted to build into my own kit, it was a no brainer for someone who values their time and knows how much trial and error can consume precious time on a hobby.
As soon as I saw the Mercury III kit I knew I had to pull the trigger when the time was right, so in October 2021 I placed my order.
I received it the beginning of January 2022.
After serving in the military in a technical position and also have been employed by numerous defense contractors, I highly value proper assembly techniques.
The assembly was not rushed as it appears some people feel that technical prowess is demonstrated by how fast they can assemble something.
I have nothing to prove and everything to gain by making my assembly as reliable and the highest quality as possible so I took my time and spent just under 6 hours assembling my amplifier kit.
Flawless operation from out of the gate and never had any issues at all!
I clocked about 100 hours of amplifier operation of FT8 and SSB voice during challenging propagation over 6 months on all HF bands, opened the amp up for a general inspection and observation of any dust buildup.
The amplifier had no obvious dust buildup on any internal surfaces and appeared to be brand new with no signs of heat stress or other issues.
I have powered this amp from both 120v and 240v and have observed identical power output operation of 1200W PEP on both voltages.
The only difference is that in my example of the amplifier, there is a tiny power supply fan that turns much faster on 120v so it has an almost annoying audible whine, but it is not present on 240v as the power supply is much more efficient, so the fan turns much slower.
I have used this amplifier from 160M-6M and observed that the gain does vary- the middle HF bands have more gain than the higher and lower bands, and linearity variances are more present on the higher and lower bands while linearity is nearly perfect over 90% of the output on the middle HF bands.
Digital modes that have a high duty cycle like FT8 are limited to less than 700W (or after 7-8 seconds the unit will trip into protection) while SSB voice has no problem reaching 900W to the rated 1200w output, but I prefer to run the unit peaking around 1Kw.
I used to service the good old URT-23D HF radio system that can generate 12,000 btu's of heat so seeing something so small generate over a Kw on my telepost meter is simply awesome!
I've used it on AM- 300W carrier with modulation peaking between 900w-1kw. I'd recommend using the fans on high in carrier based modes of modulation, but it is a super performer!
If you are a CW operator wanting QSK ops, this amp isn't for you but works well for semi break in.
If you want to use every watt of legal limit 1500W for FT8, RTTY, or other digital modes, this amp isn't for you as it is limited to less than 700W or the protection will trip in 8 seconds.
All in all I am satisfied with my purchase as it fulfills my needs as an all band HF amplifier.
I feel confident that if any problems do arise, they will be competently handled by the Mercury team in a timely fashion to my full satisfaction. AD0AR
K0WA Rating: 2022-07-13
Very Good Product Time Owned: 6 to 12 months.
I just want to join in the chorus praising this amplifier. First Solid State amp I've owned otherwise always used heavy iron. I had to wait for it and got it in kit form. Took my time and it went together very nicely and worked from the start. I am a CW Operators member so I run this amp every week hard on the CWT mini tests. I works at 1000 watts output and have run it at 1100. I ran it hard on CQ WW CW and IARU CW. Works extremely well. Used it on SSB a couple of times and got excellent reports. I must have over a 1000 QSOs with this amp. It is a great product. KM3KM is working hard to keep up production, but he is a cottage industry and waiting is the game. It is worth it to wait for one of these amps. Small, light weight and the fit and finish is excellent.

KW7XT Rating: 2022-07-12
Great easy to use amplifier Time Owned: 0 to 3 months.
I received the factory built version a few months ago. It is my first amp. I was surprised how easy it is to use. The protection circuits seem robust. I have not used the ACL connection, just the RCAPTT cable. It does not take much drive power to hit 1000 watts on my IC-7300. It has a very nice color screen that shows all you need to know about operating conditions of the amp. Great job by the designers of this equipment.
W4WEW Rating: 2022-06-24
Works great and fantastic Customer support Time Owned: more than 12 months.
My Mercury Amp worked great for about 14 months with no problems what so ever. about a week past it would not power up. I emailed Kenny and described the problem. Although my amp was out of warranty, Kenny made repairs within a couple days and returned the repaired Controller at NO cost to me - He even paid for shipping. Amp is working great again. That is what I call great/fantastic service - Kenny stands behind his product.
KW4Z Rating: 2022-05-20
Great Amplifier Time Owned: 0 to 3 months.
Even though I could have chosen to have the amp built for me I chose the kit form and I've only had this Amp a short time but my initial reaction is that this amplifier will only get better and more popular over time. The instructions were simple and the photos, and videos, helpful and come on a memory stick. I took my time building it but it isn't something that most would be able to do. My suggestion is read through the instructions and view some of the available YouTube videos about assembly then go for it.

The operation of the amplifier is wonderfully simple as the amplifier requires no jumpers to be moved to operate from 120 or 240 volts. The only thing you have to do is change the power cable and the power supply does the rest. When in AUTO as it defaults to the band is chosen automatically when you transmit through it. I will though advise anyone who purchases/orders the kit to purchase your power cord ahead of time because one does not come with the kit. I can't say anything about their customer service because I have had no reason to contact them but they have always been very prompt at answering any question I have had.

I will also say that everything about this amp is professionally done from design to the parts supplied, nothing is cheap and no shortcuts taken. I hope, and plan, on having this amp for the duration and expect that it will out last me. As for now I'd gladly purchase it again even with the wait time involved. If there is any negative it's the wait to get one but this is just an indication of its popularity with the HAM community.

Whether you purchase it pre-built or assemble it yourself I do recommend it and I've had an Ameritron ALS-1300 and an ALPHA 374A but my go to amp will be the Mercury IIIs.

I only hope (and expect) that one day Kenny will, or may, incorporate the Antenna Tuner in with the Amplifier in what may be a Mercury IV amp.
W1AEX Rating: 2022-05-12
Looks Great, Runs Great, Easy Operation Time Owned: 3 to 6 months.
I am very happy with my Mercury IIIs amplifier and would not hesitate to recommend it to anyone looking for a reliable, great looking, high performance HF +6 amplifier. I built the kit form of the Mercury IIIs and I found the documentation to be very easy to follow with no surprises during assembly and no drama with my first power-up test. Below is my short list of things I have observed during assembly and operation:

1. Very clean modular design
2. High quality components throughout
3. Beautiful touch-screen display
4. Sturdy circuit boards, chassis and cabinet enclosure
5. Excellent documentation and outstanding support
6. Auto-sense for 120/240 VAC operation
7. Band selection by RF sensing works perfectly
8. Very compatible with ANAN adaptive predistortion (Pure Signal)
9. Turn it on and it just runs smoothly and reliably on all bands

If you have never used a solid-state, no-tune amplifier you will love the Mercury IIIs. Hit the front-panel power switch, then the operate switch and a few seconds later you are running with up to 1200 watts of clean power. My ordering experience from Kenny and Angel was easy with excellent communication and no worries at any step in the process. Not much more to say except that my wife noticed the Mercury IIIs right away and her only comment was that it’s the best looking piece of equipment on my bench.

73, Rob W1AEX
WA4AIP Rating: 2022-04-14
FANTASTIC AMP!!! Time Owned: 6 to 12 months.
TERRIFIC AMP! Not a lot to expand on that has not already been mentioned!
I have had the MERCURY IIIs for 6 months+ and have not had any issues, from kit building to operation. The assembly instructions, including a thumb drive
with videos is first class. The form and fit of all the parts is a tribute to the meticulous attention to detail of Kenny KM3KM and is also reflected with his excellent
customer support and responsiveness. I have not spoken on the air with anyone having the amp that did not rave about its performance and support.
Now that it is available in completed form AND as a kit, it provides options to the perspective buyer. In the final analysis, GREAT AMP, GREAT PERFORMANCE
and SUPERIOR CUSTOMER SUPPORT - real differentiators in today's radio market!
K2WPM Rating: 2022-04-09
6 watts in 600 watts out Time Owned: 3 to 6 months.
Okay I am stupid, but I built it, so can you. Unbelievable, it actually works. Damn, it works really well. I still go barefoot most of the the time but this thing is fun. It's a racehorse.