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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.
  11. K0SPN

    K0SPN Ham Member QRZ Page

    That's not a PEP reading meter.
    Real PEP meters are powered by something other than RF.
    I also don't know how much I'd trust the accuracy of that. It's probably okay, but I'd want a known accurate meter to check it first.
  12. KM1H

    KM1H Ham Member QRZ Page

    Ive never seen an accurate Ameritron power meter.

    If you want cheap pay the $1500 for a NIB SB-220/221/HL-2200 that show on Fleabay and recap. Considering it was $350 at intro in 1969 its still a good deal.

  13. WX7G

    WX7G Ham Member QRZ Page

    No amp beats the AL811 for watts per buck. Note that to tune it a power meter is required. And be prepared to feed it new 811 tubes regularly as the quality of these tubes is hit or miss. I had an AL-811 and replaced it with an ALS-600.
  14. K1ZJH

    K1ZJH Ham Member QRZ Page

    True, but the 3-500Z tubes are much more rugged and forgiving than 811As.
    On his website, Tom W8JI admits the tubes are pushed beyond manufacturer ratings, and that doesn't leave much margin
    for operator tune up errors!

    The 811H pushes tubes far beyond ratings
    Absolutely true, if you consider operation in ICAS or CCS and not IVS. Keep in mind however the 811H does not "push" the tubes any "harder" than Collins did in the 30L1, or Heath did in the Warrior. It has been a long standing tradition to run 811 tubes at about 250 watts dc plate input, which is about 150-175 watts RF on the anode, per tube.

    I don't agree that past ham practices are a justification for pushing junk Chinese imports. New RCA tubes aren't being made these days.

    Last edited: Apr 15, 2012
  15. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    Indeed, the RCA tubes were amazing but haven't been manufactured in decades. Collins pushed the hell out of 811As in the 30L-1, knowing full well they were doing that, and the tubes rarely failed...but they were American-made RCA tubes.

    Those "NOS" RCA 811As from the 60s and 70s sell for higher prices than brand new 2012-vintage Chinese tubes do, when you can find them.

    I wouldn't want anything with 811As in it today. Even Ameritron gladly admits they're all a roll of the dice, and although they try to weed out bad ones at the factory, they don't operate them for long and some are still guaranteed to fail prematurely, even without any cockpit error.

    The "RF Parts" brand 3-500ZGs (Chinese) seem to be quite good. I've been using a couple of them for years now, and no problems thus far. I suspect RFP simply weeds out bad ones before they ship them, and eats that cost.
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