Friday, December 7, 2018

Hardrock-50 on order

Phew! I almost spent $1200 on a 100W amp - what was I thinking?!

With that order now cancelled I've been roaming the web for an alternative to the Elecraft KXPA-100. Here were the contenders (it's a short list):

Juma PA-100D kit - Chinese copy

Juma PA-100D - the big brother of this amplifier was recently ordered by DXpeditioner Tom KC0W. After 4 months, he still likes it and plans on using it with his KX3 (which will drive it to a full kw) on a DXpedition to YS (El Salvador to non-DXers) next month. But Juma's website lists the PA-100D as "not in stock". Unfortunately, they don't respond to requests for info on when it may again be available. This leads us to:

Chinee Copy of PA-100D - at what point does it become ethical to buy these pirated copies? Never? When the original manufacturer ignores its would-be customers? To many hams, ethics never enters the sphere - only dollars, and the cheaper supplier wins. FWIW, this eBay offering is an already-built version of the Juma kit.

And the winner is:

Hardrock-50 - this 50-watt amp kit has a long and stellar history. Just try to find a negative review about it. It has 3dB less output than the others ("half an S-unit" in CB-speak) and costs 3.5dB less than the Elecraft amp.

A $30 option allows this amp to automatically follow band switching commands from a KX3 and a built-in autotuner is available. Total price with KX2/KX3 compatibility, autotuner and QSK option - $557.

The amp itself, and the build process, is extensively documented and has an active forum of satisfied users.

I've known about this amp for a long time and yet never considered it due to the 50W output. It just didn't seem worth it to go from 10 watts (KX2, Anan-10e) to 50 watts (7dB).

So why now? A few reasons:

  • FT8 - my plans for an amp in this power range are to allow my Anan-10e to be a dedicated digital station. Even with the Flex (with KPA-500 available) I've almost always limited my output to 40-50 watts on FT8 and have never needed more, even when DXing on 80 meters with that mode.
  • Portable ops - from time to time I like activating parks...or just going afield for no reason at all and operating among the deer, birds and skeeters. For portable ops, on a battery, 50 watts from an amp will give me more time than a 100W amp. True, I could turn a 100W amp down to 50 watts but if I'm going to do that, why pay the extra premium for a 100W amp?
  • Compatibility with simple QRP rigs that don't have a KEY OUT jack. Although the Hardrock-50 has a PTT (KEY IN) jack it also has a carrier operated relay for keying. This means that it can be used with rigs like the Norcal 40a, Hilltopper, HW-9 and other QRP rigs that don't have the PTT output that would be required in order to key the other amplifiers mentioned here.
  • I'm spending $650 less than if I'd bought the E amp. With that savings I could fly to Calgary, stay at an AirBNB and activate (and photograph!) Banff-Jasper during the upcoming CNPOTA. That's significant - for the money I'm saving, I can fly to somewhere exotic-to-me and use my new amplifier that I built myself...if I'm willing to settle for 50 watts instead of 100...which I am. AG6QR has a more detailed comparison of this amp with the E amp here.

The Hardrock-50 with all options is now on its way to me .


  1. I had a Hardrock-50 when I used an FT-817. It's a good, solid product. You will enjoy it. Sadly these days aging eyes make it tough for me to build kits otherwise I'd have been tempted by another one.

    1. Hi Tim,

      I bet if you posted to the forum you'd find a number of people willing to build one for you for a reasonable fee. t's good to see all the positive feedback from those who own this amp and makes me feel like I made the right choice in buying it over any of the other possibilities. And I think some of my old QRP rigs will be put to use again since the HR50 doesn't need a Key In signal to activate it.

      Thanks for your comment Tim and 73,

      John AE5X

  2. HR50 forum: