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Reviews For: Hardrock-50 HF+6M Solid State Amplifier Kit

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

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Review Summary For : Hardrock-50 HF+6M Solid State Amplifier Kit
Reviews: 72MSRP: 260.00
Description:
Based on Jim Veatch's winning ARRL Home Brew Challenge II amplifier design, it's been improved and functionality has been expanded to include a new aluminum enclosure with built in heat sink, an LCD display, pre-soldered SMT components, computer control options, software upgradeable, easier to use connectors, and MORE. All software is open source and the unit hackable, including an accessible I2C header to add your own peripherals.

Kit includes 4 PCBs (3 without .5W driver) with all surface mount components professionally installed using a reflow process. Builder only needs to install through hole components; toroidal inductors, relays, transistors, connectors, etc. Also includes professionally machined case with integral heat-sink, all chassis mount components, interconnects and instruction/assembly manual. Supports auto band select (depending on transceiver) and can be driven with 0.5 watts.
Product is in production
More Info: http://www.hobbypcb.com
# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
15725
VE1RNM Rating: 2022-12-05
5 Gold stars for a superb amp with phenomenal service Time Owned: more than 12 months.
I purchased this kit several years ago based on the promise by the designer Jim Veatch that a working amplifier was included in the price. I have always wanted to build an amp but the days of Heathkit sb220's are long gone. So I inventoried the kit, nothing missing but due to repairs on our property, the amp wasn't touched for almost a year.
I started work, after reading the Manuel several times and did the construction very slowly. I should mention that this was my first kit building experience. I do build my own antennas but this was indeed going to be a different kind of cat! First I should mention is follow Jim's advise on wire strippers for the kynock wire and wind the torrids just like the photos in the guide, I'm not sure what the big deal with people hating winding these but these are T50 so bigger and fun to wind! One suggestion though, after winding, place them in PCB and mark area where the enamel wire will contact solder pad, after scraping and tinning the wires, use a dmm set for continuity. All you are interested in is a good contact between the wire ends so when you solder to the board the torrid will work.
I should also mention that all emails to Jim were answered same day when I had questions or concerns ---this is absolutely amazing after purchase service. Once completed I did need to send the amp back because I couldn't set the bias, well there was really nothing wrong with the amp, I hadn't adjusted the contrast so the screen wasn't showing anything. Here I didn't read that part of the Manuel so my fault completely.
When Jim received the amp it powered up and once screen was adjusted, he set the bias for me, and tidied up some wireing but the point is it was fully operational when he received it! So if I can build this so can You!

I use the amp on SSB and psk31 with my ft817 and it adds immeasurably to my operating enjoyment. I only run 2.5watts of drive for 50+ on SSB and 45watts on psk31.
The only comment I would add and it is a suggestion and not a negative, is for hobby PCB to offer a ready-made interface for the ft817, ND and 818 models that allows automatic bandswitching, rather than having to construct it yourself. I neglected to say that the amp works very well with the carrier operated setting on SSB but I use a plug from the access port on the 817 to run to the RCA phono on the hardrock 50 to allow direct PTT use which is flawless.

Last and not least is a big thank you to Jim Veatch for providing such an enjoyable experience.
AG7JC Rating: 2022-08-28
Excellent Amp to upgrade the KX3 Time Owned: 0 to 3 months.
After doing a lot of research on amps for the KX3 I decided to go with Hardrock 50 and Im really happy I did! The requirements I was looking for in an amp was, portability, low power usage, integrated tuner and tough. This amp delivers on all fronts.
The build is well documented and pretty straight forward. Getting the pre-wound toroids does make it easier and less time consuming but not necessary.
Also, If you run into any issues or have questions Jim is an incredible resource. He is prompt to reply and very helpful. I made a mistake updating the firmware on the ATU and he me recover it.
If your looking for a compact, quality amp for your shack or pack this is the amp for you.
73
W9MT Rating: 2022-06-21
UPDATED 6/2022: End result was worth the effort... Time Owned: more than 12 months.
June 2022 Update:

Yes, I'm a hamfest junkie. I spotted another Hardrock-50 at a very good price at a hamfest. This specimen also had the ATU, but no QSK board option (which I never used). I bought it because I have both an FT-817ND and an 818, and jumped at the opportunity to mate one with each radio. I brought it home and tried it out by connecting it to the RF cables, the original's control cable and the the PowerPole equipped DC cable. It fired right up with no issues. RF output on all bands was equal or slightly better than on my original amp. Good deal !!!

When I purchased it, though, it was part of an unbreakable package deal that included the HobbyPCB interface box to an IC-705. Right now I don't have one of those radios and really don't plan to ever buy one. Anybody out there want to buy that built up interface from me cheap? (Item SOLD for a very good price, 06/21/2022.)

Original Review:

I bought this amplifier, supposedly working, at a hamfest about two years ago. Someone was selling it for another ham that built it and was divesting of it and other equipment he owned.

It was configured to work with an Elecraft KX-3. Opening it, I was pleasantly surprised to see that it had both the optional ATU and QSK board. I modified it, via the kit construction manual instructions to work with my FT-817 series radios, including the auto-bandswitching function.

Well, it didn't work. Auto-bandswitching didn't work and the amplifier didn't amplify. The ATU also didn't work.

Jim Veatch is truly wonderful about supporting his product and design. Over 3 or 4 email exchanges with him over a 2 week period, I learned about a few assembly quirks not in the manual. These included a foil cut needed to enable the 817's auto-bandswitching capability over the CAT cable, and the fact that two nylon spacers that the QSK board sat upon were too long to allow the in-line header connectors to fully mate. So, I ground them down a bit. The Hardrock-50 snapped to life.

I also had to do two other things. I had to clean up the wire winding spacing on the ATU and harmonic filter toroids. The builder's windings were loose and not evenly spaced. Gently repositioning the windings a bit resulted in better amplifier performance. I also found that the builder had the ATU mounting turned 180 degrees from the manual's instructions. (Mounted "backwards".) The standard cabling to the ATU was now "no longer stretched".

On Jim's recommendation, I also upgraded the firmware for both the amplifier's workings and that of the ATU.

I'm happy with the end results. This is a great amp, whose designer will take great pains to help an owner (and not just the original buyer) to be happy with their investment. This deserves and gets "five stars" from me.
W8EH Rating: 2022-06-10
Great AMP Perfect for the Icom IC-705 Time Owned: 0 to 3 months.
I received this amp a few weeks ago and spent quite a few hours building it. This was the basic model with no QSK or tuner.

The hardest part was winding the toroids with my arthritic thumb. I should have ordered the pre wound toroid kit. :) That would have made it so much easier.

This was an easy build. Instructions were very good and detailed with pictures. The latest model has more of the parts pre mounted on the boards for you. The older models you had to mount all of the relays, connectors, etc. Make sure that you download the latest build instructions because of this improvement.

The amp worked the first time. Tuning involved measuring the current draw and adjusting the bias on each of the 4 transistors. Then it was ready to go.

I connected it to my IC-705 via the amp/alc jack on the radio to the PTT jack on the amp. The rig and amp play well together. Be sure to set your TX Delay to 30ms in the IC-705 to account for the relays closing, or the rig sees a high SWR for a split second on initial key up.

I did not get the optional 705 Bluetooth box for automatically changing bands, so I have to change bands manually with the buttons on the front. Not a problem. My next test will be with my Yaesu FT-817, where it will change bands automatically with the proper interface cable.

On most bands it only needs 3 or 4 watts to drive it to a full 50 watts. You can get it quite a bit higher than 50 watts on the lower bands, but they say to run 50 watts max. I was concerned at first that 20 meters doesn't quite make 50 watts (48 watts in my case on my Bird meter) with 5 watts drive. On the 6 meter band you get about 35 watts out. These observations matched with a friend who also has the HR-50. After talking to HobbyPCB, they confirmed my observations and that 6 meters was expected to be only about 35 watts out.

Overall a great amp for boosting that QRP level up to 50 watts. Highly recommended.
N0MPM Rating: 2022-03-27
Perfect Companion to QRP Rigs Time Owned: 0 to 3 months.
The HR-50 is a joy to build and easy to operate. I had a few problems with RLY-13 and associated capacitors, but with Jim's expert and timely help, got all my problems resolved very quickly.
Put the amp through its paces the last few weeks on a few POTA CW activations as well as the CQWW WPX SSB contest last weekend. Large heatsink handled heat load easily, although my low QSO rates didn't push it too hard!!
Seamless operation with my KX3 via the HR50 interface board and smooth operation using the COR function with my QCX collections.
KD8CGH Rating: 2022-02-22
Solid amp with great support Time Owned: 6 to 12 months.
Yet another satisfied customer.
I built this amp with ATU last year to use with my QRP Hermes Lite 2 SDR and KX3. I have interface boards for both rigs and the HR50 works well with both of them. Recently I made a mistake updating the firmware on my amp and thought I had bricked it. I got immediate support with a simple solution, so all is well again.
I appreciate the well proven, reliable design and great support.
KK4WXO Rating: 2021-11-22
Service after the sale Time Owned: more than 12 months.
I bought a basic amp kit at the beginning of the pandemic to celebrate passing the AE exam. As noted here it's not a beginner kit but the manual is good. The amp has served well since then with my Anan-10e SDR, so when my outboard tuner started acting up I added the Hardrock tuner module this Fall.
The tuner is also a pretty straightforward build and worked fine for a couple of weeks, until it wouldn't match anything 17m-up. Jim's email support is super fast, and after a few tests I mailed the amp in. Jim corrected a stray coax shield whisker, updated the firmware, tested it and returned it all in a couple of days.
All in all the Hardrock-50 is a very satisfying project to build, a satisfying product to own, and even a pleasure to have fixed.
KN6SU Rating: 2021-05-09
Great Kit Time Owned: 3 to 6 months.
I bought the HR-50 and ATU kits mainly to use for my QRP radios (IC-705 and TX-500) in the field when more power was needed. I looked at those compact Chinese HF amps available on line but had doubts about both their output filtering and how well they would protect the rig from things like transient spikes.

The HR-50/ATU was easy to assemble, the only real PITA being winding the toroids and stripping some of the small coated wire, but this can be bypassed by ordering prewound toroids from another vendor who was recommended by Hobby PCB. I built both amp and ATU over two days. Except for a couple of PC board holes that needed a little reaming to fit a USB socket, everything fit together nicely. The unit weighs in at 3lb plus a couple of ounces, light enough to add to the radio pack for field use, especially since it includes the ATU. Where every ounce is critical (as for high Sierra backpacking), I'd make do with just the barefoot TX-500, some wire, an Elecraft T1, and Bioenno 3AH battery. But when 3 extra pounds and the weight of a 12AH battery are doable, the HR-50 comes along.

There is great news for IC-705 users...Hobby PCB now sells a really good (and inexpensive) interface kit to link the 705 with the HR-50 amp. It weighs just under 4 ounces, links to the 705 via bluetooth, and follows the 705 as it switches bands. Of course you can directly key the HR-50 with any QRP rig and manually change bands on the amp (COR mode). Hobby PCB hasn't made a specific interface for the TX-500 yet.

The only modification I made was to substitute BNC connectors for the supplied SO-239's. This required some machining to allow the BNC's to mate with the rear panel. I wish Hobby PC would offer the option of BNC connectors, since most QRP rigs use them.

The only real gripe I had was how long it took (about a month) after I ordered the ATU for the kit to arrive. But that really was due to the extreme slowness of the USPS and not the fault of Hobby PCP.

SM0WRA Rating: 2021-03-31
Excellent amplifier and excellent support Time Owned: more than 12 months.
I have built and used my Hardrock-50 amplifier with my Flex 1500 transceiver for several years now and am very satisfied, both with the kit and the amplifier performance. And not least with the customer service which is second to none! I recently had a mishap when substituting one defect mosfet and needed a new PCB and some components. Jim responded immediately even on a weekend and dispatched my replacement order the next working day. He has also been very responsive and helpful with other queries during the years. I can wholeheartedly recommend this amplifier to anyone interested in building their own gear and equally HobbyPCB as a first class supplier of kits. 73 Per SM0WRA
K1QN Rating: 2020-10-18
Like a Rock Time Owned: more than 12 months.
Putting it together was not a walk in the park, but it functions perfectly. The wire for the directional coupler is hard to strip. I left a 1/4" slack on all leads, and needed it on 1 of the 4 leads. The QSK board is printed with the three connectors on the wrong side.

That said, the thing is just perfect on the air. I've been building kits and hombrewing for over 50 years, and this is the first kit that worked perfectly, right out of the shop. No debugging, no problems to diagnose. Just amazing!

I'm using it with a Proficio which provided 5 watts input. I get 50+ watts out on all bands. (I don't run 6M.)

The only problem, which is hardly worth mentioning, is that I've had some EMC problems, especially on 40M. This was cured with a handfull of ferrite line chokes.

The support was fast, and right on target. It's like they were there in the shack.

Now that it's been on the air for a couple years, I have to say it's one of the most reliable pieces of gear I've owned (50+years as a ham). It just sits there and does the job!