• You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.

Got a new toy today - MX0P50A HF amp

Moleculo

Ham Radio Nerd
Apr 14, 2002
9,194
1,674
283
I just got a deal on this from a local ham who used it once or twice with his Elecraft KX3 and then bought something else. This is the older model of the MX-P50A, HF amp, which was built in China.

mx-p50a.jpg


I think the bent heat since was damaged in initial shipping to him, but it doesn't affect anything. If you're familiar with the size of the KX3, you can tell that the amp sitting next it it is pretty small. It runs 10-80 meters with a band switch on the front. It has the ability to auto-sense the band and switch automatically but that doesn't work with this radio. The specs I found online indicate that it will do 50-60 watts with 5 watts drive; my initial tests into a so-so meter show about 40 watts with 7-8 watts of drive. Since the MX-P50A does not have an internal tuner, my plan is to use it with a little MFJ 904H tuner, which I already own.

This should make a nice little portable setup for my RV, where I typically use a Buddipole antenna (in a variety of configurations) at 20' on the back of the RV ladder. For the price I got it for, increasing the power output from 10-12 watts on the KX3 to 40 is a nice little bump

Update:
I just realized that I forgot to turn of the internal ATU on the KX3 when running the tests. Even into a dummy load, turning it off made a difference, apparently due to a slight impedance mismatch between the rig and amp with it turned on (using whatever the last ATU setting was). I now see full 50 watt output on bands 20-80 meters with a slight drop to 45 watts on 10m. Hey, 10 more watts is 10 more watts!
 
Last edited:

I have been using a silver cased P50 for over 2 years now with my KX2. I see normally 50 watts on 20 metres. Its a must for these trying conditions for northern NA SOTA. 12 watts from the KX2 is mediocre right now.
 

dxChat
Help Users
  • No one is chatting at the moment.
  • dxBot:
    Tucker442 has left the room.
  • @ BJ radionut:
    LIVE 10:00 AM EST :cool:
  • @ Charles Edwards:
    I'm looking for factory settings 1 through 59 for a AT 5555 n2 or AT500 M2 I only wrote down half the values feel like a idiot I need help will be appreciated