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write your own review of the Henry 3K Classic.
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K9KXQ
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Rating: 5/5
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Jan 26, 2006 22:50
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Henry 3K MarkII X (3CX1200A7)
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Time owned: 0 to 3 months
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Well what can you say about the Hery that has not been said already, this is the 3rd Henry I've owned, and it takes 2 men and a mule to move it.
Built to last like a brick house, the only disadvantage that I can say is the noise from the massive blower, this thing is very loud and fills the shack with wind tunnel noise.
Got to be a better way to cool the 3CX1200A7 to cut down on the background noise, oh well looks like a w2ihy with noise gate.
k9kxq
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W6IML
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Rating: 5/5
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May 1, 2005 14:38
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Best of the Best! 8877 version
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Time owned: more than 12 months
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After owning several legal limit HF amplifiers, both home brew and manufactured, I must say that these Henry console HF amplifiers are the best of the best. Mine is the 8877 version, and after several tests, it has very little ripple on the D/C supply, and tunes with no problem on every Ham band from 3.5 to 30 meg. It doesn't have 160 capability, but since I don't use that band, I don't mind.
This Henry 3K classic will be a part of my shack till I go SK!
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W4QG
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Rating: 5/5
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Nov 28, 2004 06:02
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MASSIVE!! (8877 version)
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Time owned: more than 12 months
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Super heavy duty amplifier. As has been said, the power supply is very very heavy duty. The amp is not perfect however, 160m would be a great plus. So would QSK. The blower is very loud - sounds like a jet engine... (there are much quieter blowers out there if you are inclined to replace it.) On the plus side, you can run this amp for days at legal limit with 65 watts in. Will tune on the WARC bands no problem.
Weighs about 200 pounds...
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WO2Y
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Rating: 5/5
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Oct 21, 2002 20:56
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Heavy Duty
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Time owned: 6 to 12 months
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I have owned several amps over the past 40 years, but this amp is the best constructed of them all. I purchased the amp used and had a problem with the power supply. The people at Henry, Bill, Ted, Lucy, were all great. Everyone did all that they could to get me back on the air. Bill offered to test parts, at no cost, and offered testing suggestions. A new HV transformer was the answer, and it was shipped quickly, at an excellent price. Small parts that I felt should be replaced(although probably not necessary) were shipped quickly. The service from the salesfloor to the factory is best described as top notch. I highly recommend the amp, and as an added bonus, the Henry amps produce the strongest, cleanest signals on the bands.
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W4AN
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Rating: 1/5
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Jun 1, 2001 15:50
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Hmmm...
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Time owned: more than 12 months
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I had the same AC hum problem with my 3K Classic. I called the factory and they said "We've never heard of such a problem". Interestingly, I had spoken to another 3K Classic owner who reported the same problem to the same person at Henry 6 months prior to my call to Henry. I figured short memory or some such. But then another ham I know called them 1 month after my call. Had the same problem out of the box, and the same person at Henry knew nothing about the problem.
As Bill O'Reilly says... I'll let you decide.
73
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N5DF
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Rating: 3/5
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Jun 1, 2001 15:27
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A good amp but it has some flaws
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Time owned: more than 12 months
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I purchased a new 3K Classic X about a year ago. Over the past year, I have examined extensively the design, material and workmanship of this amplifier. In what follows, I will relate much of what I found, both good and bad.
First, the amplifier is relatively large and heavy. It arrived on a transfer truck, and the operator had to use a motorized fork lift to move it from the truck to my garage. It takes two strong individuals to manhandle this beast. In my shack, the amplifier rests on a small dolly with casters so that I can roll it around on the carpeted floor (I removed the four short "legs", or "stands", that came on the amplifier). Before purchasing this amplifier, examine carefully the space you have available and your own physical abilities/limitations for dealing with large, heavy objects.
With the amplifier came a poor instruction manual. When reading the manual, I got the impression that, over the years, the amplifier's design was changed, but the manual was never updated to reflect these changes. For example, the amplifier contains a "step-start" circuit, but the manual contains no mention of this.
As noted in several reviews that you can find on the net, blower noise is significant. It comes from a large Dayton blower that is mounted inside the power supply deck.
The power supply is the best part of this amplifier. Henry "got it right" when they designed the power supply. It uses a conventional full-wave rectifier (not a bridge). On the front panel of the power supply deck, there is a high-voltage switch that switches between two positions on the secondary of the transformer. Also, the power supply is protected by a large, front-panel-mounted circuit breaker. A resonant choke input is used. There is a massive set of bleeder resistors that keep current flowing (through the choke) so that the benefits of a choke input filter are obtained(also, the bleeders keep the shack warm in the winter!). Regulation is excellent. Under all load conditions, AC ripple is extremely small(very carefully, I measured this quantity).
The RF deck is an enclosed chassis that slides into the amplifier upper case (which contains meters, switches etc.). From the blower mounted on the bottom side of the top plate of the power supply deck, air flows into the bottom of the RF deck (the bottom of the RF deck is a flat surface that rests on the flat top plate of the power supply deck).
The RF deck is supposed to be a pressurized chassis with air flowing up through the tube and out the top of the chassis. However, the top plate is not large enough to cover completely the top of the RF deck. There is about a half-inch gap between the back of the top plate and the back of the RF deck (on the back of the RF deck, there is a half-inch crack that runs the width of the chassis).
I consider this to be a significant design flaw. When leaving a pressurized chassis, air should flow over hot surfaces, not cold surfaces. Also, the top plate does not lay flat on top of the RF deck, it rests on top of the plate choke. Yes, the plate choke is a little too long, and it sticks out (only very slightly) of the top of the RF deck. The top plate is "bowed" slightly to accommodate the plate choke protruding out of the top of the RF deck.
I fixed these "fit and finish" flaws. With angle aluminum mounted on the inside back panel of the RF deck, I sealed the above-mentioned half-inch crack along the back of the RF deck. With a hack saw, I cut off about a quarter inch of the plate choke top. Now, the top plate does lie flat and form an air seal on all four sides of the RF deck top. Finally, in the top plate, I drilled three small holes directly over the tank coil (the tank Q is very high and the rotary coil can get hot). These modifications greatly increased the volume of air through the tube and around the tank coil. Now, from the pressurized chassis, most of the air leaves after immediately flowing over hot surfaces. Also, it might be my imagination, but sealing (except for the tube and coil vents) the RF deck seems to have reduced slightly the blower noise from the amplifier.
I received reports of AC hum on my signal when I first put the amplifier on the air. On a monitor scope, I could see AC ripple on the RF output, about 40% modulation depth. Investigation of this problem revealed an incorrectly wound filament choke. The filament choke is wound on a conventional toroid core, a winding on each half of the core (the choke is not bifilar wound, mainly because of mounting/structural requirements, I suspect). In my amplifier, the two filament choke windings were wound so that a common-mode RF current (equal magnitude and phase in both windings) produced fluxes that cancel out (I give the Right-Hand Rule credit for this one!). The inductance offered by the choke was minimal! After much experimenting, I have a new filament choke that is wound on a larger (than what came with the amp) core. My "fix" did the job: no AC ripple can be seen on the monitor scope.
As mentioned above, on most bands, tank Q (as defined by E. Wingfield in his August, 1983 QST article - this is the definition used in recent editions of the ARRL Handbook) is very high (my measurements and calculations indicate a loaded Q of at least 20 on several bands). This makes difficult amplifier adjustment and tuning (on 10meters, tuning is very difficult!). Also, it results in high circulating tank current and low tank efficiency. Currently, I am redesigning the Pi-L output network. My goal is to keep tank Q in the range of 12 to 15.
Twice, in a very professional, polite and controlled manner, I have e-mailed the factory with detailed technical questions. So far, I have not received a response to my technical questions (no response what ever - just like I never e-mailed them in the first place). However, I hope they have used my technical data/information to improve their product. I rate customer support as being poor (I know that this goes against the claims you see on some commercial web pages - and elsewhere - of "legendary Henry customer service").
As discussed above, the amplifier has good and bad points. The flaws I have found can be fixed. However, fixing the problems takes time, money and considerable technical knowledge/abilities.
John, n5df
Huntsville, AL
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KM4KF
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Rating: 5/5
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Dec 10, 1999 12:27
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3K Classic X MK II (3CX1200A7)
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Time owned: unknown months
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One pharase that comes to mind in describing this amplifier is: "Industrial Strength"! Everything about this amp is geared towards durability. The
power supply is beyond heavy duty ( the plate transformer alone weighs more than many legal limit tabletop models ). The tube employed
( Eimac's 3CX1200A7 ) with it's 50 watt grid dissipation is indestuctable under normal usage, adding to the amplifier's overall toughness. If there are any drawbacks to be mentioned, it is that the amp also comes with an "industrial strength" blower which really lets you know the amp is there when running. Also, when changing bands the roller inductor "tune" control can take quite a few turns. Henry has remedied this by offering a matching crank style tuning knob which makes switching bands much easier ( perhaps Henry will include this knob on future amps??? ). In any event, the positives way outweigh the negatives. This is in my opinion the best, toughest manual tune amplifier on the market today. If you want a trouble free amplifier that your great-grandkids will be able to use, then this is the amp for you.
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K1XT
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Rating: 5/5
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Sep 2, 1999 16:27
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Henry 3K Classic-X w/8877
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Time owned: unknown months
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There is simply nothing like a Henry. Everything is heavy duty. I bought mine from an estate sale and after a few modern mods such as an electronic 3 minute timer it has worked flawlessly. With 4200 volts on the plate, it does 1500 out with 40 watts in on all bands including 10 meters. With 50 to 55 watts drive it does 2000 out. It has a tuned input for each band and a nifty test point on the back of the amp to check the filament voltage. The power supply is heavy and well regulated. It makes most table top amps look like toys. Yes, Henrys are big, but if you take a peek inside you'll see why.
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