Is there any factory made HF amp, which beats AL811 in watt per buck ratio?

Discussion in 'Amateur Radio Amplifiers' started by 4L4AGU, Apr 13, 2012.

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  1. 4L4AGU

    4L4AGU Ham Member QRZ Page

    I'm speaking about factory made amplifiers, which includes power supply, swr meter, alc, whatsoever, the one you can just unbox, connect and work. I mean only new ones, not rebuilt, refurbished, homemade or recycled military ones.
  2. W1QJ

    W1QJ Ham Member QRZ Page

    maybe not for watts per buck, but certainly with problems per buck.
  3. K1ZJH

    K1ZJH Ham Member QRZ Page

    Considering that the 811 tubes have been pushed well beyond manufacturers specs in commercial ham amps (RCA specs show
    no color for the plate in CCS) I'd go for an amp that uses 3-500Zs. AL-80B is a good amp, but it also pushes the tube a bit hard.

  4. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    The AL-811 does not include an SWR or wattmeter of any sort. I think the AL-80B is actually a better deal because it does include a very good peak-reading (and quite accurate PEP) SWR/wattmeter as well as other features not found in the 811 series and runs more power from a single tube than the 811 series can run with three or four tubes.
  5. KJ4AQU

    KJ4AQU Ham Member QRZ Page

    Or maybe even it's older brother the AL-80A or even heathkit SB-1000 (kitted version of it). Granted no SWR meter but I would say it's nearly as good as the 80-B. And also uses a single 3-500z. JMO
  6. KO6WB

    KO6WB Premium Subscriber QRZ Page

    In the power range the AL811 is capable of there are just about no choices. If you did want more power then everybody's suggestion for an AL80B is very good. Due to my current living arrangements an AL811 works okay. The tubes are cheap and it has been very dependable for me, so far. Some of the owners have installed 572B's in theirs and report good operations. The 572B is a more expensive tube and those that have put them in the 811 series amplifiers are hoping they will last longer. They might but not always. The 811 and 572 tubes have some problems with QC and the only place producing these tubes is China.
  7. 4L4AGU

    4L4AGU Ham Member QRZ Page

    According to price/wattage comparison, AL811 got $ 1.33 per watt, while AL-80 got $ 1.46 per watt.
  8. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    Sounds about right. But again, the AL-80B has a PEP watt/SWR meter internally which is worth about $150 (if you had to buy the same meter and use it outboard). The AL-811 doesn't. If you add the cost of the meter to the 811, the 80B starts looking cheaper.
  9. 4L4AGU

    4L4AGU Ham Member QRZ Page

  10. W9GB

    W9GB Ham Member QRZ Page

    Alex -

    The Economics of your question (for vacuum tube HF amplifiers) comes down to a few critieria --
    that are subject to component costs and production of RF tubes.

    1. There are specific "fixed costs" for an HF amplifier, these are:
    -- Chassis & Control: Amplifier box and Associated meters, Indicators, Control board, Tube Filament supply, RF Output/SWR metering, and knobs
    -- High Voltage: Plate transformer, Recitification, and HV capacitors (for smoothing rectified DC)
    -- Multi-Band & Radio Interface: Band switches, Tank circuits, T/R switching, for sequencing, tuning, and loading
    2. The "variable cost" is the selection and availability of the actual RF tube(s).
    Ceramic tubes have replaced traditional Glass RF tubes in medical, industrial and broadcast usage.

    For Glass RF Tubes, there are 3 common RF amplifier candidates that are produced today for other uses.

    EL509/EL519 - Eastern European TV Sweep Tube (~ 15 kHz). Produced in former Yugoslavia/Eastern Europe, Russia?

    811A/572B - The 811A, developed by RCA, widely used in Audio (200 Hz - 20 kHz) amplification, and the more rugged
    572b are produced in China and Svetlana in Russia (572b). Tesla in former Yugoslavia?

    3-500z - Last of the glass RF tubes still in production. Primarily China mfg., amateur radio is tube's primary market.
    3. SO, when I look at your question -- I view it with a bit more complexity, this way:

    -- Tube(s) Ratio: Cost per Watt (RF Output) for the tube(s) selected in HF amplifier.
    The ratio will be in a range (e.g. $1 to $2 per watt) that has increased due to production costs.

    -- Non-Tube Ratio: Cost per Watt (RF Output) for remaining non-tube costs for building an HF amplifier.
    Following standard economic principles, these relatively fixed costs are generally favorable (regardless of tube) --
    the more RF Output that the amplifier produces.

    SO, it really comes down to the RF Tube and the Box.
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