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| Reviews Summary for Commander HF2500 Magnum |
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Reviews: 4
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Average rating: 4.5/5
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MSRP: $5,000
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Description: FCC approved (2) tube version of the Command Technologies Export model.
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More info: http://www.command1.com
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write your own review of the Commander HF2500 Magnum.
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AB2JL
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Rating: 5/5
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Jun 16, 2008 14:12
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A Very Good Amp
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Time owned: more than 12 months
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i've had this amp for over a year now with no problems short of a fuse blowing once.
the amp produces legal limit at 20 or so watts. using a flex sdr-1000 to drive it at 20 watts is good because it keeps the heat down in the flex.
it's more amp than you will ever need, but then again, it isn't a matter of need.
the manual is a bit sketchy but that is a minor issue.
i have the amp in a shed (literally) out in my backyard. doing nothing but idling, the amp produces quite a bit of heat, thats nice in the winter but it forces me to run an air conditioner in the summer.
it's definitely a 9.9 out of 10 in any case.
phil AB2JL
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W4PIG
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Rating: 5/5
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Jan 25, 2008 12:39
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GREAT AMP
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Time owned: 0 to 3 months
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THIS IS BY FAR THE BEST AMP I HAVE EVER OWNED. THIS IS A POWER HOUSE LOW DRIVE GIVES LEGAL LIMIT WITH NO STRAIN AND LOTS MORE IN STORE IF YOU NEED IT. PAT IS GOOD WITH ALL YOUR NEEDS ARE QUESTIONS FAR BETTER THAN ALPHA EVER WAS ALPHA DONT HAVE ANYTHING BETTER THAN THIS AMP. ALSO I NOTICED ON THE REVEIWS SOME ONE PUT A 4 RATING ON THE 2500HE 3 HOLE MODLE ON THE MAGNUM REVIEW THIS NEEDS TO BE REMOVED TO THE PROPER REVIEW AREA. THIS IS THE 2500 MAGNUM WITH A PAIR OF 3CPX800S NOT THE 3 HOLE MODEL. WHAT A AMP AND THE # 1 CONSTUCTION IS GREAT 73S
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K6AER
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Rating: 3/5
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Nov 8, 2007 19:01
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Needs attention to detail.
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Time owned: 0 to 3 months
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I just finished repairing a Command Technologies HF-2500E. This is the export three hole model that uses three 3CX800A7’s. The amplifier had flat tubes that affected the tuning and required substantial grid drive just to get 2000 watts. Upon inspectation I noticed the tubes were from different batch numbers. This is something you really don’t want to do when running tubes in parallel. You want each tube to have the same characteristics. According to the owner these were the original tubes shipped with the amplifier in 1995. He never was able to realize the full potential the amplifier was advertised to do.
The manual is poorly written and a bit scattered in the flow and little technical detail. Schematics were basically the two tube version with a schematic insert of the three tube RF deck. In some places in the manual there are references to 4CX800 tubes??? In the operation section the manual references grid current limits for a two tube amplifier and you have to be careful when accepting the operational current figures. It would appear little effort was given in the technical writing of the manual. Schematics are inconsistent with connection dots on some points and none on other depicted connections. This is just sloppy documentation you would not expect here in the states.
The input Pi network is switched with a series of relays (located under a rear panel) from a wafer switch located on the front just a head of the model 86 output bandswitch.
The power transformer is a brute weighing about 85 lbs. Care must be exercised when placing it into the amplifier cavity. I noticed the blower was quite noisy reading 62 dBa on my sound meter at 19 inches in the front. As a table top amplifier you will want to place it away from your microphone operating position. My Alphas run about 50 dBa at the same distance.
Power out is as advertised. On most bands I was able to obtain 3600 watts out with a two tone SSB signal at 60 watts drive. The spectral picture look good with harmonics and inband spurs 50 dB or better below the rated output. 1500 watts out was obtainable with 20 watts drive.
Power output was lower on 80 and 160 meters due to toriods being used for the Pi networks and having a lower Q and more loss. You could load the amplifier up on 17 meter in the 15 meter position by using your transceiver auto tuner to make up for the input miss match. An interesting design note is the amplifier puts out 750 watts of heat in the operate mode with no carrier. I would seem it is biased closer to class A then AB2. There is no active bias circuitry.
The two tone transmitter IMD measured about 33 dBc at 1500 watts. I did not test it a full output for there is no point in doing so. Here in the colonies we are limited to 1500 watts.
Area of disappointments are the location of the high voltage stack and rectifier board. It is located under the input tube plenum chamber with the complete RF deck built on top. If you pop a diode, resistor or filter capacitor on this assembly you are in for many hours of disassembly. You cannot get to the assembly from the bottom. A fix would be to have an access cover on the bottom but I’ll bet Pat Stein, the owner, will never give in on that idea.
For the most part the amplifier is well built but it greatly lacks the attention to detail for repair and some assemblies lack sophistication such as the meters being glued in with RTV. The PCB’s have no component locators and a lot of reverse engineering is needed when repairing the unit.
Bottom line is the unit puts out lots of power but it is no Alpha in fit finish and design. If you own this amplifier you need experience in home brew amplifier repair if you are going to keep it for awhile.
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KC8OKG
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Rating: 5/5
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Feb 24, 2007 07:32
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Legendary quality- Lifetime HF Amplifier. 160-10m
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Time owned: 6 to 12 months
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Purchasing this amplifier has been one of the best decisions I have made since becoming a ham. You will not find a better company to deal with or a better man to deal with than Pat Stein. Because of the price of quality HF tube amps, it took me some time to research the issue and come up with a good choice, since there are many out there to choose from.
Command Technologies products and his satisfied customers speak for themselves.
Rock solid quality material and craftsmanship, this amplifier is built for a lifetime which is what I was after.
The amplifier is legal limit with much headroom.
It just performs flawlessly and effortlessly as it should day in and day out.
Although many companies use the Russian surplus tubes as a money saving measure, you cant beat the Eimac pulse rated tubes. If I have to bet, I would guess that in years to come the Eimac tubes will be around in some form-not so sure with the surplus tubes. Just my opinion.
One thing that sold me on the amp and was an obsessive point of mine was having the cleanest amp I could afford to buy. Pat Stein's amps are the cleanest of clean which can be attributed to his personal design expertise and the quality of the components he chooses like the genuine pulse rated 3cpx800a7's in this amp. Check out the 3rd order IMD numbers on his products. Try to find an amp with better specs. Alpha's in the same price range- with the Russian tubes- not even close in terms of IMD performance! Some people say that 3rd Order IMD is not important-I disagree.
Pat designed and built amplifiers that are being used today at W1AW! If you check out his website, the picture of him was taken at W1AW with his amplifier/s in the background.
If he is good enough for W1AW, his quality is good enough for me, KC8OKG!
After ordering the amp but before receiving it, I continued to obsess about my purchase, wondering if I made the right choice. I continued to discuss the decision with every ham who had any experience with Command Technologies. I could not find 1 ham, that had anything less than favorable to say about the product. Even his competition had great things to say about his quality.
Now that I have used the amp for about 10 months it has far exceeded my expectations.
Approx 20-25 watts input on 20 meters yields legal limit. The amp does 1500 watts without breaking a sweat and is capable of much, much more. Pat gives the pulse rated tubes higher voltage than standard 3cx800a7's to yield more power and efficiency. With this amp remember that you are paying for the tremendous headroom not just a few hundred watts of headroom. I dont have a dummy load that would withstand what this amplifier is capable of so I wont try.
The amp weighs over 100 lbs. The power transformer weighs over 50lbs itself. Other components like the bandswitch are super heavy duty. None of the components of this amplifier are a compromise as far as I can tell. If you are in the market for an amp, take your time and compare them all. The Commander will shine through whether it be the standard 2500 or the Magnum.
If you like to buy many throw away items and recycle them often, forget this amp. This amp is a keeper for those who plan to get old with ham radio. Also, when you call Command Technologies, you will talk to Pat Stein. I have never talked to his answering machine---ever--and I have called many times. If you call him you will see what I am talking about. His warranty is excellent too.
In conclusion, a great amplifier, a great value, no compromise in material and workmanship, the best service and quality. Like they say. "Built like a Tank". Also, this amp has the feel and appearance of good old made in the USA. They are worth the wait. I am proud to have one. Thanks for reading my post. Sincerely, Greg Sarris 73-KC8OKG
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