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Reviews For: DX World-e 500W HF/6m LINEAR AMPLIFIER

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

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Review Summary For : DX World-e 500W HF/6m LINEAR AMPLIFIER
Reviews: 1MSRP: 850 Euros
Description:
500W HF/6m Linear Amplifier with LDMOS NXP MRF300 x2. RF Input: 0-40W custom per order. RF Output: 0-600W Max. 160m-6m. All modes.
Product is in production
More Info: https://www.dxworld-e.com/product-page/hf-6m-linear-amplifier-500w
# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
1515
G4GTP Rating: 2023-01-31
Superb amplifier at a great price Time Owned: 6 to 12 months.
I consider this amp a very well-kept secret as there don't seem to be many about and I was also surprised no reviews on eHam for the 500W version and only two for the 1000W version.

These amps are hand-built to order by SV2RIF. As a result they almost constantly show "out of stock" on the website, such is the length of the waiting list, and that's no surprise. After every build Dimitris places a video on YouTube of every individual amplifier in test phase prior to dispatch.

So I was on his waiting list, but one became available used here in the UK. It was too tempting to pass-up, so I purchased and sent apologies to Dimitris. I don't think he was too worried as he seems to have more orders than he can cope with.

The amplifier I purchased had been configured for 40W input. I wanted to reduce this to 5W for use with my Hermes Lite 2 SDR. I contacted Dimitris. What a gentleman. Patient and helpful at all times both with my questions before I joined his waiting list and also afterwards with questions on how to perform mods to my used amplifier. Superb service.

Mine is the Mk.1 version. There is now a Mk.2 with a few minor improvements.

To best my knowledge these are the amendments:

1: The fan on my Mk.1 version has two speeds, low and high. The latter is noisy (too noisy) when it cuts in on the higher speed. The newer versions have constantly variable control of the fan. Dimitris has explained the mod (with full drawings), I just have not got round to doing it. This will solve my only "must-do" issue with this amplifier.

2: The PTT switching time on the Mk.2 has been made faster to accommodate semi-break-in CW operation. Again, on my list of "to-do"s. It's an easy one resistor swap-out.

3: The output LPF band filter ranges have been slightly changed. Not sure why. This version seems to function perfectly OK.

There is no auto-bandswitching as standard but the bandswitch pin-outs are brought to a multiway socket on the rear so a band decoder can easily be added. Dimitris does offer his own band decoders as an optional extra. See his shop website.

The LDMOS protection circuits are extremely good and fast. I've done some stupid things already, mostly the bandswitch in wrong position or too high a power applied before lowering the SWR. Protection has performed faultlessly with no damage to the output devices.

Yes, it's a basic amp, but who needs more? It's solid as a tank, nicely put together, reliable and easily outputs the rated power and more (up to 600W on some bands). Output is very clean as verified by viewing my own output both on local receivers and also web SDRs. I often receive complimentary comments on the strength of my signal and also the transmitted quality.

The amplifier is very easy to open up to work on with plenty of space inside. There is no integrated power supply so it does need a good quality 50V power pack but these are readily available as used PC server power units. Mine cost just £10 on the well-know auction site and is the ubiquitous ELTEK Flatpack 2 3000W supply. They always seem to be available. There is plenty of information it the web about how to change the output from 48v to 50v.

So all in all a great product with a couple of very minor issues that have now been fully addressed in the latest version. But I think this one will last me out. It's a keeper for sure. Thank you Dimitris for a great and affordable amplifier.