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RF Amplifier Tubes- whats left & affordable for a RF Amp

Discussion in 'Amateur Radio Amplifiers' started by N8FVJ, May 4, 2019.

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  1. W7RY

    W7RY Ham Member QRZ Page

    Russian "4CX800" (as their called) are junk. And hard to find, and when you do, they are expensive. They never had 800 watts of plate dissipation, and sockets are expensive too.

    8877 is the only way to go!

    Although I been using my homebrew 3CX800 amplifier in RTTY contests (1500 watts output) for 25 years on the original Eimac tubes (X2) and they are as good as the day they were new!
    I also use my homebrew 8877 amplifier for the second radio in RTTY contesting (1500 watts ouput) as well.

    Jim W7RY
    K2XT likes this.
  2. K9STH

    K9STH Ham Member QRZ Page

    I don't know about the Russian tetrodes and pentodes. However, the Russian GI-7b, GI-7bT, GS-31b, and GS-35b triodes all work very well in grounded grid configuration and they are still readily available.

    The GS-31b and GS-35b are the same tube except for the heat sink. The GS-35b has a much more massive heat sink and can run more power. The heat sink is removable from both tubes. As such, it is possible to "convert" a GS-31b into a GS-35b and vice versa.

    My 160-meter, home brew, pair GI-7bT amplifier works very well and I am slowly working on a couple of amplifiers that use the GS-31b. In addition, I have several GI-7bT tubes waiting to be included in amplifiers for VHF and UHF.

    Glen, K9STH
    K6LPM likes this.
  3. N8FVJ

    N8FVJ Ham Member QRZ Page

    No doubt the 8877 is a great tube. Tompson makes new 8877s for about $1100 and for that money I need a warranty. Used tubes are a crap shoot. For $850 you can get the whole amp such as a AL-80A or AL-80B that will produce up to 1KW PEP out. I saw a mint AL-80A on QTH for $400. If you get unlucky with a soft tube, a new quality Chinese 3-500z is $200. Still less money for an entire amp vs a new 8877 tube.
    Last edited: Jun 24, 2019
    NQ1B likes this.
  4. W2VW

    W2VW Ham Member QRZ Page

    The best bargain tubes don't stay bargains if people talk about them.
    K2XT and AG5CK like this.
  5. MM0IMC

    MM0IMC Ham Member QRZ Page

    I love my dirty, commie, filthy ruskie red junk!;)
    W2VW likes this.
  6. AG5CK

    AG5CK Premium Subscriber QRZ Page

    I've noticed that. I'm careful about giving too much detail when I leave feedback on Ebay so the seller doesn't jack the price up.

    I've got 6 gs35b tubes so we can talk about them. :). Good for the money but I wasn't smart enough to make one linear enough for my OCD.
  7. W7RY

    W7RY Ham Member QRZ Page

    I'm glad you have had good luck with them Glen.
    73, Jim W7RY
  8. K4QE

    K4QE XML Subscriber QRZ Page

    Ameritron AL82s have chimneys for their 3-500Zs. It's one of their big selling points along with the 3.3kV under load on the plates.
  9. W1QJ

    W1QJ Ham Member QRZ Page

    I'm with Jim, W7RY. The 8877 is the ultimate tube. If you have a single 8877 and it works it will last you long enough until you come across a few "deals" on at least two more that will last you the rest of your life. The was an Ebay seller who sold medical pulls at a fair price with a guarantee. If you send him a PM he would probably give you a deal on multiple ones. I you have 3 spares you'd be set for life.
    KK4RSV likes this.
  10. W7RY

    W7RY Ham Member QRZ Page

    Last 3CPX1500 tube I bought on eBay from and estate stale was $250.00. It was an Eimac with a early 2000 date code.

    It was guaranteed. I tested it as soon as it came in the door.
    Works perfectly!

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