Amps
My love. I love building and operating amplifiers. I have built 6 to date and am considering my next project. Most of the amps that I have built, I have used for a while then sold. My first was a pair of 813’s. It went to a local ham, Bill KB5VTZ. We lost Bill a while back and I have no idea what happened to that amp. Probably found its way to the Belton Hamfest.
Next amp is a 4 x CX250B’s. I still have that one in a rack but have not used it for a while. Put the right voltage on the plate and that amp was stout.
3rd amp was a single 3-500 in a grounded grid config. I still have that one and use it whenever I just need 6-700 watts.
4th Amp was a GS-35b GG. 10-80m legal limit. Tuned input, vacuum relays and capacitors. Not sure why I sold that one but I did.
5th Amp was a pair of 3-500z. I used a variac controlled 5KV PS that I also built and still have. With 3200 steady volts on the plate, this amp was rock stable. Sold it 2 years ago to another local ham.
6h amp was a pair of GS-35B’s. Never got this thing to work the way I wanted to. Tank circuit was an infinite problem. Sold it last year.
I currently operate a Henry 2k modified with a stout power supply and 8877 tube. Step start, grid protection and all the bells and whistles of modern day, computerized amp. I use this thing daily on my Icom 756ProIII.
Connected to my Yaesu FT-950 is a Rare Sigma XR-3000D. This has a pair of 3-500’s , tuned input in a double shielded cabinet with a 60 pound power supply “STOUT”. This amp was produced in the early 1970’s in Japan and had a very limited exportation. Big 4 inch meters, simple to tune and operate and an honest 1500 watts out.
Connected to my IC-7000 my all time favorite an Alpha 78 modified by N4UQ )Dick Byrd to a pair of 3cx800a7’s If you ever need an Alpha worked on, send it to a true PRO. Dick is truly an Alpha Master. I call this my Lazy mans amplifier as I have a tendancy to just leave it in the bandpass settings as I go from band to band. Hit it with about 65 watts and 1500 comes out, it is truly phenomenal.
Connected to my Kenwood TS-940 is my Homebrew single 3-500Z. It is rock stable, tunes easily and gives me an honest 700 watts when I need it.
I have owned just about every amp there is at one time or another and have settled (for now) on the above amps in my shop. If you haven’t tried building an amp, read some books, take some safety precautions (HV won’t kill you, but the current will) and have some fun.
73’s Richard N5OU