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Reviews Categories | Amplifiers: RF Power - HF & HF+6M | Henry 8K Ultra Help

Reviews Summary for Henry 8K Ultra
Henry 8K Ultra Reviews: 5 Average rating: 4.4/5 MSRP: $$7800
Description: The Henry 8K Ultra is a 2 piece Ham Radio Linear Amplifier running a single 3cx3000a7 Ceramic Tube. The picture is of the desktop unit and the optional extended prest unit. Great amp built like a tank!!
Product is not in production.
More info: http://
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WA3JPY Rating: 5/5 Nov 29, 2016 16:28 Send this review to a friend
Best High Power Production Amp Made  Time owned: more than 12 months
I have to say that I was surprised and dismayed to read the report on this product from KA1SEL. I have had quite the opposite experience. I have loaded this amp into a 4.5:1 VSWR without anything bad happening. Not the smartest thing in the world to do, but I needed Navassa on 160 and loaded up what I had. Point is, legal limit out on 160 into a 80 meter OCF and the amp worked flawlessly. So much for padders spaced too close together. I have beaten my 8K up pretty badly working DX and it has yet to give me one second of trouble. Power? How much do you want? The downside is that you can't drive this amp with 50 watts and get huge numbers. You need to have something to drive it with, as in a FTdx-9000MP. 200 watts drive will typically give you all you will ever need, and it will last forever. The final is a 3CX3000A7 and for the power out, this is a cheap tube. To really tune it correctly requires an outboard digital power meter, like the Array Solutions Power Master II, or something like that. Tune for max output, at given drive. Yes, get max on tune before increasing drive and setting load, but that is pretty much it. You want a MINIMUM of 6 gage wire to the 220 outlet. And think big when it comes to antenna design, or things will simply melt. As a RTTY amp, 1500 watts all day long with no issues. Since this amp is no longer in production, it would help to know what you are doing if you plan on purchasing one. They are not cheap, and that is for a GOOD reason. Bottom line, you need to be able to fix it yourself, which may be a problem if you really smoke it. But if you know what you are doing with amps, this one beats every other one. And as a ham with 49 years of experience, I say that based on one heck of a lot of experience.
KA1CDE Rating: 5/5 Jun 11, 2014 17:09 Send this review to a friend
The Very Best Amp  Time owned: more than 12 months
The Henry 8K is an amplifier is what I consider the top of the line amplifier. The 8K was underrated at 5000 watts output or as Henry says "conservatively rated" The 8K will deliver about 20 times its drive input, so 75 watts in delivers about 1500 watts out, but about 400 watts input is max.
Inside the Henry 8K "EVERYTHING" is large, heavy, top of the line, bird watt meters, remote operation, tuning is easy, tune for max output with desired input level.

The Amp weighs in at 350lbs, servo motors perform the tuning as you dial in the setting from your shack, the tube 3cx3000A7 requires no warm up, which is necessary since the amp must be shutdown before changing bands.
The amp was designed for someone who knows how to tune an amplifier, there are NO safe guards that will trip the amp if you make a gross error, you must pay attention to the details when tuning up. A Henry 8K in great shape is worth $10K or more if condition warrants it.
The last Henry's made can be told by the Lettering that says HENRY is now Yellow, not black, and the 8K on the remote head is now red instead of black.
Henry improved the amp over the years, earlier amps will need up dating, the last Henry 8K have all the updates.
If you get a chance to own one, you will have a piece of history with the Henry Ampliers.....
KB1SEL Rating: 2/5 Jun 22, 2011 18:04 Send this review to a friend
Not worth the money  Time owned: 6 to 12 months
I owned a Henry 8k which was made in the mid 90's. I bought it second hand I installed all of the updates. To be able to have your noisy amp away from you while you talk so you don't have to hear the noise or feel the heat is a great idea. But this amp has some major design flaws like the roller inductors which are custom made by henry and cannot be replaced which wear out and fail and the flappers which switch in more capacitance on the plate side which are way to close to the doorknob caps which end up arcing to them since they are at ground potential.There are just to many flaws to list.It doesn't matter what power level you are producing the amp isn't worth the money. I sold mine and bought something else. After I did all the work to the amp it worked like new. But the design flaws forced me to sell it.
8KULTRA Rating: 5/5 Mar 26, 2007 16:32 Send this review to a friend
Second to None  Time owned: more than 12 months
The Henry 8K ultra is the heaviest duty amp of them all, by a long short:

The amp weighs 350 lbs:

Plate voltage is 6000 volts unkeyed.

Plate transformer rated 1 amp continous, 2 amp intermitent.

The control Head measure plate current, Plate volts, Grid current, Filament voltage.
5000 watts forward power, 500 watts reflected power.

The amp is tuned remotely with the control head which is pictured here, the rf/power supply can be used 100ft away from the amp.

The amp covers almost all frequecies 1.8 to 30 mhz, there are just a few odd balls it does not cover.

Tune up is easy and straight forward, tune for max out put.

The amp uses a 3cx3000 A7 for the final tube.
When you look in the amp, the components are larger and heavier than any Amp I have ever seen,
These are big components, BIG and HEAVY DUTY.
350 lbs worth.

DRIVE: OUTPUT: Meter Coaxial Dymanic

100 w ~2000 Carrier
200 W ~4400 Carrier
300 W ~6000 Carrier
~350W ~7600 PEP


ALL, I stress ALL components must be able to handle the output, even to a dummy load like I have done testing it.

Antenna switches, coax, antenna, must be able to handle the power you plan to use>

Amp needs a 230 volt source rated 50 amp minimum.


The amp can run 24/7 at 1500 watts out put, The blower is loud, but since it is remote, I can't hear it, but have heard some Dentrons almost as loud>

Henry has stopped making HF amps: To bad, they could have raised the price to $12 - 15K for this amp, and there is not one amp that would come close to comparing the Henry 8K Ultra.

Why buy an amp that can run much power than you can use ? Why have an amp that is capable of being used for commercial needs ?

Don't buy it to run all the power, but if you have to have the best, than there is no finer amp ever made or that even come close.

KC5TJT Rating: 5/5 Oct 9, 2006 06:33 Send this review to a friend
HENRY 8K  Time owned: 0 to 3 months
Well.. What do you say?? GREAT AMP.. 50 watts in is 1.5KW pep out.. 100 watts in 2.5KW pep out.. 150 watts in 3.5KW out.. You could just keep going!! I was told it will take 400 watts drive power.. BUT WHY??? I love that the RF Deck is remotly mounted.. It eliminates the NOISE AND HEAT problem.. I really wonder if there is anyway to burn it up>> The way it looks to me an M1 Abrhams couldnt tear it up.. Its a very HD comercial quality unit!!

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