Elecraft Amplifier to be announced at Visalia CA Hamfest

Discussion in 'Amateur Radio Amplifiers' started by K2HAT, Apr 20, 2017.

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  1. N2EY

    N2EY XML Subscriber QRZ Page

    Advertising, yes....

    Also consider this:

    How many HF ham rigs manufactured in 1999 are still on the market today, besides the K2? 18 years on the market....impressive.

    Note that the K2 uses all through-hole parts, no SMT.
  2. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    The 374 (I had one, also -- back when they were "new') didn't use any control circuitry, just a bandswitch with two settings per band: Tuned, or bandpass.

    The "bandpass" only really worked with well matched antennas; but if you had those, it was pretty slick. No control circuitry required, so everything about it was mechanical. The original 374 had only two weak links I could find: The bandswitch itself (failures were not unusual), and the cooling system which was very quiet but also pretty minimal, using a muffin fan and ductwork. They replaced the muffin fan and ductwork with a centrifugal blower in later models, and that did run the tubes cooler.

    But if you didn't use it on RTTY and stuck with mostly SSB or a mix of SSB/CW, it was cool enough. Very elegant design.
    AF6LJ likes this.
  3. K2HAT

    K2HAT QRZ Volunteer Volunteer Moderator Volunteer DX Helper QRZ Page

    When was the Kenwood TS-2000 introduced? Must be close to 18 years.
    AF6LJ likes this.
  4. NQ1B

    NQ1B Ham Member QRZ Page

    Based on simple math, tube amps are an absolute steal compared with solid-state amps. :D

    Price of tube-based amps:
    Ameritron AL-811H, ~600 watts, about $900
    Ameritron AL-80B, ~800 watts, about $1500
    Ameritron AL-82, 1500 watts, about $2800
    ACOM 1000, 1000 watts, about $2800
    ACOM 1500, 1500 watts, about $4000
    Cost per watt: $1.50 - $2.80

    Price of solid-state amps:
    Ameritron ALS-600, 500 watts, about $1400
    ACOM 600, 600 watts, about $2800
    Elecraft KPA-500, 500 watts, about $3000
    Elecraft KPA-1500, 1500 watts, about $6000
    ICOM PW-1, 1000 watts, about $4900
    Cost per watt: $2.80 - $6.00

    So it's still not practical to get the same performance *at the same price* from
    solid state power amplifiers. It will come, but it's not here yet.

    I love Elecraft products, and I'm sure the KPA-1500 is a great amp. But it's an amp for buyers
    who want all of its features, including built-in autotuner with instant retuning, memory, etc.

    AF6LJ likes this.
  5. WA7PRC

    WA7PRC Ham Member QRZ Page

    For the difference in price between toob and SS, I'll stick with my toob SB-220. The main functional difference appears to be the ATU in some of the SS amplifiers. My antennas have tuning that are pretty broad (worst case) 2:1, so the pi network works fine as-is. That leaves resonating of the tank, which takes only a second or two. :)
    AF6LJ likes this.
  6. AF6LJ

    AF6LJ Ham Member QRZ Page

    Tube Amps
    There is more hand labor in a tube amp.
    A bunch of hand soldering that cannot be avoided.
    A large amount of the hand wiring cannot be terminated in connectors and just plugged in, but a siginificant amount can.
    A lot of screw turning in a tube amp that must be done by hand, some can be automated but at what cost.
    It is relatively cheap to build vacuum tubes, you don't need exotic vacuum systems or ion implanters.
    If a tube is built wrong it can be reworked at most stages in its manufacture.

    Sold State Amps...
    Can take advantage of automated board assembly.
    Toroids can be wound by machine, better than a human can.
    Fewer screws to be turned by hand.
    A relatively small amount of hand soldering is necessary.
    There special handling and installation that must be done by a human, such as PA transistor installation,
    Heatsink and spreader installation.
    Heatsink and spreader machining can be done by CNC, even surface grinding of mating surfaces.
    RF power transistor manufacturing is costly, requires exotic ultra high vacuum systems, ultra pure materials, ion implantation and special handling skills at every step of the manufacturing process.
    Yields are small... And the newest devices are made in Class 50 or better clean rooms.

    Some things need to be overcome before solid state amps cost the same on a watts per dollar as the higher end tube amps.
  7. AF6LJ

    AF6LJ Ham Member QRZ Page

    If I had to pay for my labor (I charge $35.00/Hr for computer work) I would have been better off buying an Alpha 91B, but it wouldn't have been near as much fun.
    Bad Oscar will be fun also. :D
  8. WA7PRC

    WA7PRC Ham Member QRZ Page

    Yah. I bought my SB-220 in 1975 used, w/ two good toobs for the princely sum of $275. Can't touch that today. I should get off my duff and work on my homebrew GS-35b 160m "amplefire" :D
    AF6LJ likes this.
  9. AF6LJ

    AF6LJ Ham Member QRZ Page

    Bad Oscar came to me from a friend who had it die on him one day, he boxed it up and said "Sue you want my 221?" What else could I say but, tell me how much you want...
    He pulled the tubes boxed them up and sent me two boxes...
    It's a basket case and I want a new project, and a One-Sixty Amp....
    WA7PRC likes this.
  10. N2EY

    N2EY XML Subscriber QRZ Page

    All true, but there are some other issues to consider......

    1) Getting good glass transmitting tubes (811, 3-500Z) for popular tube amps is a chancy game nowadays. Sometimes you get lucky - sometimes you don't. Maybe the quality will improve.....maybe not. The tubes in the ACOMs are better - but more expensive.

    2) Most of the "low-cost" tube amps are manually tuned - which is fine for the casual operator, but not for the serious contester. All the solid-state amps are no-tune.

    3) Some tube amps will work into SWRs worse than 2:1 without a tuner. Not so much SS amps.

    4) Low-cost amps tend not to include QSK nor remote operation. The higher-cost ones do. Of course that only matters for CW.

    5) Total effect on the electric bill varies with the amp, power supply, etc.

    In short, "price" depends on what you include in the total system package.


    In the late 1950s, Central Electronics made the 600L amplifier, which ran a single 813. Not the legal limit then, but a step up from the typical 50-100 watts of the time. The 600L had no tuning controls - it used a patented broadband coupler that matched the 813 output impedance to 50 ohms.

    73 de Jim, N2EY
    WA7PRC likes this.

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