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Anyone have issues with Amplifiers?

Discussion in 'Amateur Radio Amplifiers' started by K3SK, Mar 19, 2020.

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  1. K3SK

    K3SK Platinum Subscriber Platinum Subscriber QRZ Page

    I probably should have posted this before placing an order with them. o_O But, is there anyone using high power amplifiers made by If you have one have you had issues with the operation, quality or performance?

    I'm in the middle of implementing what may be a life changing event, well at least it feels that way. I've decided it's time to let go of the past century's technology and replace my 1970s and 80s amplifiers. For the past several weeks I have been updating and repairing some of the stuff I've built and modified for ham use over the years and find myself not liking the poking around in the high voltage. It never bothered me before, but in recent years it kind of creeps me out some. Beside that, it is getting harder to find components and other hardware to upgrade or even build new stuff from the old designs. My plan is simple. Spend way to much money and buy and/or build solid state "low voltage" high power amplifiers.

    I placed an order for an HF-6 meter and a 2 meter KW from Looking at the photos on eBay, and their web site I like the look of the workmanship. Even better, I like their pricing which is 1/2 or less for comparable amplifiers almost anywhere. Over the next year I will most likely buy parts and semi-complete modules and build amps for 222, 432 and 1296 MHz. Now I need to spend time on
    eBay, searching for high current 50-53 volt power supplies.

    Oh, if anybody ask, Yes I am colluding with the Russians. ;)
    K3RW likes this.
  2. W4NNF

    W4NNF XML Subscriber QRZ Page

    I have yet to lay my hands on one in person. What I've been told? Very well designed, but you have to be on the lookout for problems with workmanship....unsoldered connections, cold solder joints stuff like that. Look forward to hearing how you like your amp!
  3. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    I think if they ship a very good bottle of vodka with it, you're all set.:)
    N2AMM and W4NNF like this.
  4. N0NSX

    N0NSX Ham Member QRZ Page

    I saw your post on the HF amp, I have been looking at them, but haven't pulled the trigger yet. Did you get the 1 kw pallets and all the filters, protection, ect? I have been looking at the 600 watt units with the cheaper mrf 300 device , if you blow one, 27 bucks better than 180. I was going to use the combiners and put two together along with filter and the other stuff, shouldn't be much loss with this setup. On power supplies ebay has some 3000 watt 50 volt HP BL20p /253232-001 for 68.00, I heve read there maybe some birdies at 1.8 mhz thou. What kind of duty did you have to pay to get them in US?
  5. W1TRY

    W1TRY XML Subscriber QRZ Page

    I don't have one but I'm subscribed to the group on
    It's gotten active recently with discussions about temperature and component cooling/thermal compounds.
    Might be a place to look for discussions from actual users.
  6. K3SK

    K3SK Platinum Subscriber Platinum Subscriber QRZ Page

    Tom, I got the 1.2KW unit. Less that that would only make me mad. :) I bought the completed package. It arrived today. It is shipped with the case not assembled around the chassis. I think it has to do with their mail system. I haven't assembles or hooked it up yet. Probably not before Sunday as I am helping my son move. No import duty that I paid. It came in the mail in 2 boxes. Its a really small light weight package.

    I bought two Eltek 3000 watt server supplies as they were recommended by several people. They are somewhat difficult to adjust as its done via Can Bus and there aren't any aftermarket controllers for them. A guy is Australia makes one but he is out of stock and hos no idea when he will have any more. The default voltage is 53 volts and they are rated at 55 amps. I bought a few blank connector interface cards and parts to physically connect to them. Here's a link to my Facebook post on it.

    I also ordered the 2 meter KW. I ordered it over a week before the HF-6 amp but have not received it yet. The COVID19 has held up almost everything coming out of Russia. I emailed when I got the tracking status that the HF-6 amp had arrived at US Customs. They were surprised and said that they were told nothing was leaving Russia as there were no mail planes going to the US. My 2 meter KW passed through outgoing Russia customs on 2 April, but has not yet reached the US.
    Last edited: Apr 24, 2020
  7. WA4SIX

    WA4SIX Ham Member QRZ Page

    There are CAN shields for some of the arduinos. I know that the Due has 2 CAN outputs. Do some research in this area, as it can help you along rather cheaply.

    KD2ACO likes this.
  8. N0NSX

    N0NSX Ham Member QRZ Page

    Good luck on the moving, that's always a lot of work. I joined the group and reading the posts, seems to be issues with relays and temperature on the higher power unit, looks like they were running CW. Not any discussion on the 600 watt units. I purchased a Nice Dual redundant 50 volt 3000 watt Telco supply several years ago, I now I have a use for it. It has 4 separate 750 watt modules, with 4 outputs, so was going to run two of the 50 volt supplies ,one to each 600 watt amp pallet. I have a left over chassis for a TV amp we used to build that has a massive heat sink and ducted fans. I plan on running SSB, so duty cycle is lower and might not need all the cooling. Good luck on the testing of Amp and keep us posted how it's going.
  9. K3SK

    K3SK Platinum Subscriber Platinum Subscriber QRZ Page

    First -- The 2 meter KW I ordered cleared US Customs yesterday. USPS should be delivering it tomorrow (Monday 27 April).

    I finished assembling the case for 1.2 KW HF-6 amplifier without any significant issues. The one minor thing so far was the cheesy chassis ground lug on the back panel. It wouldn't tighten well enough against the ground wire. I threw it out and installed a 10-32 stainless steel screw, star washer and locking nuts. Now I have a good ground connection.

    After some testing on the dummy load I finally hooked the amp to the rig and antennas today. It works very well. Full power out on all bands with about 70 watts drive. Power was measured using my Bird 4410.

    I worked a few DX contacts on 20 and 15 meters as a test. In general I got decent reports. One report concerned some noise on the transmission that I will comment on below.

    While operating there were several annoying things I came across that will get further attention. The first is having to hook up 2 separate power supplies. The amp needs 50V for the PA and 13.8 for the control and monitoring circuits. My plan for resolving this annoyance is I am going to install a "Buck Step-Down Linear Regulator" and connect it to the 50V input. This will provided the needed 13.8V with more than the needed 1.2 amps. I bought a couple of these prebuilt on ebay for $2 each. :) They are very small and will work. The 2 meter and 430 amps have these circuits built in already.

    The next annoyance is a combination of several things. There is no Standby/Operate switch. When powered on the amp defaults to no band selected and if you key the transmitter the High SWR circuit triggers. The same happens if you key the transmitter and have the amp set to the wrong band. To clear this error you have to remove both the 13.8V and the 50V power and then restart. Part of this will be resolved when I receive and install the band decoder I ordered. The amp will then automatically follow the band selection from my FT-2000 so I won't be keying into the wrong band setting. I may also add a standby switch, but shutting the amp off while setting the tuner will be OK for now. Removing both power voltages to clear an error is required for all errors (SWR, over current, over temp etc.) The 50V high current input to the amp is not switched. The power switch on the front panel only switches the 13.8 volts. My plan to make this easier will probably be to add an external relay of some sort to turn off or disconnect my 50 volt supply. It will be part of the power supply control interface I am going to put together.

    For the PA 50 volts I'm using an Eltek 3000 watt server supply. It is controlled via a CAN BUS interface. I was able to land one of VK4GHZs Arduino based controllers he designed and builds for the Eltek supplies. ( ) This will give me full control of the power supply settings. When it arrives from Australia I will build a cabinet for it and then add the appropriate switching and relays to be able to turn the Eltek supply off without pulling the plug.

    One of the DX stations I worked commented on a noise in the background while I was transmitting. Running some test afterwards I found I could hear it in my headset if I turned on the audio monitoring of the FT-2000. It is definitely coming from the power supply. I switch to my second supply and got the same noise. It is not there when I initially transmit, but gradually gets louder the longer I transmit. I need to do more investigation but it appears to be caused by the power supply fan or something else as the power supply heats up during transmission. If I key the mike without audio it will eventually quiet down. It could be switching noise, but that shouldn't correlate to fan speed. More to follow on this issue.

    As of now, the 1200 Watt amp works as advertised and so far I am happy.
    W1TRY likes this.
  10. N0NSX

    N0NSX Ham Member QRZ Page

    I am glad you survived the move, sounds like you have been busy. The PS Controller looks really neat. You might try some cores with a few wraps of wire around the DC power , might eliminate some RF coupling noise. I ordered one of the 600 watt MRF300 pallets from Victor. If it works out, then I will order the other boards to build up a 1.2 kw unit. Looks like I will have roughly 800 bucks in parts to build up a unit. I ordered the first board off of Ebay, but it's a lot cheaper to order from his web site. He said shipping was pretty slow because of the virus stuff and might take a couple of months to get boards, looks like a summer project.
    If this works out, I may build up another one from some left over Military Loud Speaker Audio amp chassis we used to supply to the US Army PSYOP. They have two massive heatsinks with a 1500 watt 24 vdc to 48 vdc power supply that met a mil spec 461d spec, If I remember it was -75 db down radiated from 100 khz to 1ghz, pretty quiet, they cost about 12 grand apiece from Lamdba back in the day.. You can buy a couple 12 volt 70 amp HP server supplies for less than $30.00 and make up a 24 vdc supply to run the other one, a little kludge , but cheap way to make 48vdc

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