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All 4-1000 gurus step inside

Discussion in 'Amateur Radio Amplifiers' started by W4EKY, Jan 16, 2017.

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  1. W4EKY

    W4EKY Ham Member QRZ Page

    Can you give me some more info on the gs35b.. i like the fact that the cathode voltage is around 12.5v. The filament supply would be a piece of cake. Is this tube grid driven, grounded grid or will it need a screen supply? What kind of bias does this tube require and max plate voltage and current?.
     
  2. K9STH

    K9STH Platinum Subscriber Volunteer Moderator Platinum Subscriber QRZ Page

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  3. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    The "Russian triodes" are a very good deal...lots of suds for the money.

    However as far as I know they are no longer being manufactured, so every single tube is "NOS" (new old stock) that some day will run out and then there won't be any.

    On the plus side, they are still readily available and being metal-ceramic tubes probably have a very long storage life. Eimac metal-ceramic tubes seem to have an "infinite" storage life so far. I'm still using 4CX250Bs from the 1960s that work perfectly. Ditto for an 8877 manufactured in the 70s.

    I must admit, I still like the nearly room-filling "glow" of a 4-1000A, though.:p And the 4-1000A has a cheap and easy to find Johnson ceramic socket that works perfectly with it: I've never used the expensive Eimac socket and the tube doesn't seem to care.:)
     
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  4. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Nearly indestructible tubes, either way.

    Only reason I used 4-1000As was to grid-drive them and take advantage of all that gain. People are amazed when I drive it with my little FT-817ND at 5W and the amp delivers a bit over 400W output. Can't do that with GG anything.
     
    AF6LJ likes this.
  5. W4EKY

    W4EKY Ham Member QRZ Page

    At one point in time, i dabbled into the AM phone equipment. I had a johnson viking ranger with a hammarlund sp-600 receiver. A real close friend of mine owned and operated a viking valiant. The ranger did somewhere in the neighborhood of 30-50 watts out, that is easy to work with into a single or dual 3-500z amplifier. Id love to have a restored Valiant and 390a receiver in the near future. Inthink that GG 4-1000a is going to be the best match for that equipment.
     
  6. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    The Valiant will drive a 4-1000A in GG very well, probably too much to remain legal (remember that pesky 1500W PEP limitation, which with full modulation is 375W carrier power).

    Then, you could use a really low-powered AM exciter and the 4-1000A grid-driven and save a hundred pounds, a lot of heat, and quite a lot of money. Valiants in good working condition are very pricey today.

    If you're interested to see the power supply design (schematics, pictures, etc) for my homebrew 4-1000A amp, it's here: https://archive.org/stream/73-magazine-1985-07/07_July_1985#page/n51/mode/2up

    Same amp (RF deck part) was on the cover of CQ magazine for February, 1985. That's me turning the screwdriver. Yes, HV was disconnected.:p

    [​IMG]
     
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  7. KD0HY

    KD0HY Ham Member QRZ Page

    Steve, Is that Pete on the cover with you?
    Always enjoyed reviews and such from the 2 of you.
     
  8. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Yes, that's Pete KT2B there with me. He took the photos of my amp project for the article.

    Pete's a really good photographer (a pro, with a Masters from Syracuse U. in the field) and unfortunately no longer active but he keeps his ticket renewed. Hope he gets back on the air!
     
    AF6LJ likes this.
  9. AC8AC

    AC8AC Ham Member QRZ Page

    looks like a 6 meter amp pictured there Steve sweet !!!! wish that tube was avalible as the 3-500z . tubes need to glow visibly to be a real ham amplifier .

    yup all rusky tubes are nos but there nice to learn with my first amp I build was with a 46b on 6 meters . I now have a 31b on 6 cause I had a rewound bs220 transformer laying around and the tube was $90 shipped . but keep in mind much of the data on the net using Russian triodes is not accurate . filament transformers are easy too as mouser stocks any Hammond you may need for this use

    some basic tube data needed the 35b cathode impedance is about 40 ohms @ 4kv loaded and cathode to grid C will be 24pf +- a couple and grid to anode 12 pf +- a couple . I built a 20 meter mono bander with one . suggest about 33v bias gave me about 170 mills no rf idol . hot tube needs alc too keep you on the legal side . mono bander made about 1800 pep with 100 drive quite effortlessly
     
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  10. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    I think they're very available (used/pulls) as lots of low power BC stations used them and all went or are going solid-state. That was many years ago; by now, they're likely "all" solid state.

    I picked up two of them in perfect shape (pulls) for $100/each, so that was cheaper than new 3-500Zs would be. I still see them at the local swap meets for about that price. Unless it's been drop[ped or been used 24/7 for years and years, the pulls are likely all good, or at least good enough to deliver 1500W output power.
     
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