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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: 59MSRP: 260.00
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:
# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
KM4BPE Rating: 2019-11-07
Best little amp Time Owned: 0 to 3 months.
I bought this amp to run with my Elecraft K2 and it performs great. I have the new K2 interface that they just developed that connects seamlessly. I can get up up to 70 watts , but prefer to run at 50 just to be sure I don't end up cooking something. It is very simple to set up, and I couldn't be happier with its performance. If you have a question during or after construction, you can count on an email response almost immediately.

Oh, and it is built stronger than a tank as others have mentioned.
N8NN Rating: 2019-10-10
Superb amp for your QRP radio Time Owned: more than 12 months.
This amp is all it's advertised to be and more! I was initially concerned about building it for fear of making a mess of it, but the HardRock team says they won't let you fail... and they won't. I enjoyed building the amp, antenna tuner and QSK board.

The HardRock 50 is a perfect match for my KX2. They work together flawlessly. Going from 5-10 watts to 50 watts makes all the difference in the world for a portable station. Going from 50 watts to 100 watts isn't so significant, so the HardRock 50 is a real bargain for the price and performance when compared to other alternative amps.

I highly recommend the HardRock 50 to anyone who needs to add a boost to their QRP rig. You won't find anything better out there in either price or performance. I've had my HardRock 50 for more than two years, use it all the time and never a single failure. Get one!

Bert N8NN
K4EES Rating: 2019-07-31
Great, lightweight amp for QRP radios Time Owned: 0 to 3 months.
I’m not going to rehash the comments others have made, but will add some from my experience with the amp.

In the recent past, I bought a Elecraft KX2 for QRP and POTA (Parks on the Air) activation. I found that the KX2 12w was just not adequate for voice and sometimes for CW. 10 contacts are required to consider the park ‘activated’ and I left a park more than once wishing I had the option to easily add more power to be able to complete activation.

I looked at the KXPA 100 from Elecraft, which is a 100W amp with built-in ATU. IT lists for $1189 assembled or save $50 by putting it together yourself. It weighs in at 7 pounds and puts out 100W and, since it’s made by Elecraft, seamlessly integrates with KX2 or KX3.

I also looked at the Hardrock 50 from HobbyPCB, which is a 50W model that weighs in at under 4 pounds with all the options. The options include an internal ATU, a QSK board, and a PTT interface to allow automatic band switching and PTT switching from KX2/KX3. Price is $299 for the bare amp, add $179 for the internal tuner, $49 for the QSK board, and lastly $30 for the interface for KX2/KX3 bringing the total to $557 for all the parts.

I opted for the later after I considered the S-meter difference between 50W and 100W.

I am a fairly experienced builder having built a couple of QRP radios and tons of Arduino Ham projects. This is on par with the most complicated kit I’ve built.

Assembly was straight forward. The manul was well-written and only lost me on a couple of spots that I was able to pickup with a little effort. There are several toriods to build, but the wire is of proper size and so they were easy for me to build with no errors made. Note that for wussies, there is a link to the ‘Toroid Guy’ who will ship you toroids wound, tinned, and ready to go into the kit. I spent about 6 hours building and testing the bare kit. After the bare radio build, I spent another 4 hours building the ATU, wasting about an hour on a confusing point in the manual, which I should have caught, but could have been explained better.

When I finished my kit, it calibrated properly, but wouldn’t put out any power. I searched high and low, but couldn’t find a problem, so contacted Jim Veach who gave me some ideas about where to look and offered to fix it for me for the price of shipping it to him. I gave it my best shot and sent it back to him. He had it turned around and back to me in less than a week ready for me to complete the ATU installation. Jim guarantees you a working amp with the purchase and he stood good to his word. He found a hidden strand of coax shield that I had wound with the conductor on one of the leads, repaired it and shipped it back to me in a day. Turnaround with shipping was less than a week. Fantastic service.

With the ATU installed and bench testing done, I headed to the field to try to activate a POTA park that I had missed earlier due to too few contacts. Of course the bands have a lot to do with it, but on that day I maded 32 contacts in about an hour, with 2 to Canada and one to the US Virgin Islands. 30 of them were voice, which had previously been almost impossible with the bare KX2 and 12 watts.

SO as a review of what I bought, what I wouldn’t and what I do and don’t like:

The HR-50 is lightweight and small. It’s half the size, about half the weight, requires less power and about half the price of a fully kitted KXPA 100. It powers easily with a Bioenno 12v 12AH battery. If your antenna doesn’t require a tuner, you can get busy for $299 and about 6 hours building time.

I run with a simple end-fed 53’ wire antenna hanging in a tree with a 40’ counterpoise. The tuner is not needed on most of 20M and 40M. The $179 tuner is fantastic and tunes quickly and I’m glad I bought it and installed it. It can easily be installed afterwards if you want to try your setup without it.

The QSK board will take a mechanically noisy relay out of the system and will allow you to run up to 25wpm CW and still hear background racket. For me, this isn’t required, but mine has it installed should I ever want it. Again, you can save $50 and not install it. If you choose to add it later, you DO have to remove a relay you installed allong with two terminals and build 2 coax jumpers. This isn’t trivial, but can be done if you choose to add it later.

For the PTT interface…. don’t buy it unless you want to interface your KX2/KX3 to a computer through the interface. Instead, for the KX2, buy 2 cheap cables from and heat up your soldering iron, read the manual carefully (thank you Jim for fixing the website), and make your own cable and avoid adding a board that can easily get disconnected in the field.

WIthout the PTT interface or cable, your additional rigup beyond your bare radio is putting the HR-50 between your radio and antenna and powering the HR-50. WIth this rigup, choose the COR keying option on the amp. You will need to switch bands with the buttons on the HR-50. IF you have the PTT cable/interface, you need to plug the into the radio (one cable only for KX2, 2 cables for KX3) and the bands with change with your KX2/KX3 band changes.

The menus and setup are about as simple as it gets. 4 buttons on the front control everything. If you don’t have the PTT option, you will need to change bands with the push of the up/dn band button. If you have the Tuner option, you initiate a tune by hitting the tune button on the radio and then hit the Keyer button on the amp. It stops when it finds a solution.

For me, service is king, and Jim responded to me quickly when I had questions and repaired a self-induced fault and turned the radio around in a day and back to me in less than a week. Couldn’t ask for better service.

What would I buy? If I had funds for what I want, and I do, I would buy the bare amp and add the tuner later. I would probably avoid the QSK option. I would build my own cable for PTT.

What I don’t like:

- The amp has SO-239 connectors, but is primarily intended for QRP type radios, so I had rather see BNC connectors and avoid 2 more adapters. I’d have paid an additional $5 (hint, Jim) for this option and still might change to BNC.

- The DB9 connector on the back of the radio should have a way to attach the PTT interface board to the radio. It easily comes off in the field. The board is useless to me, so I made my own interface.

- The manual needs a section for KX2 specifically. It’s treated like the stepchild to the KX3, which interfaces completely differently.

- There is a bit of confusion in the manual concerning the interface between the amp and the ATU board. You need to build the radio without the tuner then install the tuner after alignment. I actually desoldered cables I didn’t need to because this part was confusing, built it wrong, then put cables back as I had them due to this. Could have been better described.

This is my honest opinion which might not agree with others who likely have a different radio setup, antenna, and ham mission than mine. I was not compensated for this review and I bought all of my own kit.

ken - K4EES
AE5X Rating: 2019-07-03
Well worth all the 5.0 ratings Time Owned: 6 to 12 months.
I've had my Hardrock-50 for about 8 months now and it has been a fantastic performer. I use it mainly with my Anan-10e on FT8 but also with a variety of other QRP rigs on CW.

One of the main benefits of this amp is its ability to be used with simple QRP rigs that don't have a PTT out jack - the HR-50 has a carrier-operated relay that allows incoming RF to key the amp.

I have the QSK board and ATU built into my HR-50. Power out put by band (with 2 watts drive):

6 meters - 56 watts
10 meters - 65 watts
12 meters - 67 watts
15 meters - 71 watts
17 meters - 65 watts
20 meters - 43 watts (5 watts drive needed for 50 watts out)
30 meters - 44 watts (3 watts drive needed for 50 watts out)
40 meters - 61 watts
60 meters - 50 watts
80 meters - 68 watts
160 meters - 60 watts

An awesome little amp.
N5IIA Rating: 2018-09-25
Spectacular!! Time Owned: 0 to 3 months.
I just finished building the Hardrock-50. I followed the instructions to the letter, and it worked as soon as I hooked it up. I am using it with my MCHF qrp rig, and 2 watts is all that is needed to drive the amp to 48-50 watts on all bands. If you are looking for a quality amplifier to assist your qrp rig during bad band conditions, this is the ticket. Take your time building it. Follow the instructions to the letter, and you will not be disappointed.
WA3DNM Rating: 2018-07-03
Great fun to build and operate Time Owned: 3 to 6 months.
Kit quality is wonderful, as is the support. Assembly straight forward with excellent instructions. Fired up 1st time and worked gang busters. Gives my Anan 10E 50 watts punch with 4-5 watts of drive. Took me a few days to configure DDUTIL for integration, but amp follows radio perfectly. Cannot be beat for the cost and fun of building my own amp. Have hit it with 12 watts unintentionally and it just keeps (hard) rocking out!
K3FT Rating: 2018-07-02
A1 Top Rated!! Time Owned: 6 to 12 months.
I am very pleased with the product and the service. If I could rate the overall satisfaction level with Jim and Curtis as a 10, I would.

You cannot go wrong with Hobby PCB.

Excellent is another way of describing their products and support!

Earlier 5-star review posted by K3FT on 2018-02-25

This amp is a winner, I have enjoyed the build and the very extensive help that HobbyPcb and Jim Veatch have given to me. The amp works perfectly with my KX3 and look forward to a fun relationship with it and other Hobbypcb products. Building the Amp and the ATU were not difficult. The support from Jim at Hobbypcb including fixing my errors was over the top. I cannot say enough positive about Jim, Curtis and their support staff.The quality of the products are first quality and the build instructions are Heathkit quality!!

All of the positive press about this company is valid,deserved and earned.

G4AON Rating: 2018-05-22
Solid performer Time Owned: 3 to 6 months.
I bought mine second hand, then added the QSK board. The interface to my KX3 was an easy wiring job and the amp switches perfectly, both band switching and PTT.

While I don't use full QSK, it does work to about 22 WPM.

Mine had a spurious switching spike that may not be present on other units. It was easy to see with an oscilloscope monitoring the output. I resolved the issue by adding a 220nF SMD cap across C1, C2, C3 and C4.

With the increased standing current from the more recent instructions (150 mA per device as opposed to 50 mA), only around 2W of drive is required.

Overall, a very useful addition to a QRP rig.
AI6B Rating: 2018-05-21
Best bargain in ham radio Time Owned: 6 to 12 months.
I built the amp, with ATU, about a year ago, with good performance, driving with an Elecraft KX2, 3 watts, into a 80/40 trapped dipole.

Several weeks ago I began experiencing problems tuning on the 40 meter band. After email exchange with Jim Veatch, we were unsuccessful at diagnosing the problem, so Jim suggested that I send the amp to him for repair. Less than a week after I put it in the mail, Jim emailed that he had fixed the problem, installed the updated back panel (which I had purchased), replaced the "soft" power switch and mailed the amp back to me. When I requested an invoice for the repairs, I was told that there would be no charge, although I could reimburse him for the return postage if I saw fit.

Where else can you get this kind of personal service? I consistently get 70 watts PEP (as shown by the HR50 watt meter, I have not calibrated that). That's only about 2 dB down from the 110 that I get from my Elecraft KXPA100; for a lot less money. Anyone wishing a bit more power from their QRP rig should seriously consider this little amp. Plus, you get the fun of building it.
K6WGX Rating: 2018-05-01
Great for getting 50W from 2W Time Owned: 0 to 3 months.
This thing puts out 50+ watts on all advertised bands with only about 2W drive from my FT-817D. It is a rock of an amplifier. As long as you do not feed it too much average power (about 6W) it can transmit into a 20:1 load. I recently had my CCAmp killed by an auto-tuner that went wacky, then I bought this. Life is now good.
I had to spend, maybe 8 hours assembling this thing, I did buy the pre-wound coils. This was the first kit I built since about 1975, when I did a DX-160 from parts.
Nothing bad to say. Support is excellent.