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Thread: Ameritron AL881 vs ALS600

  1. #1

    Default Ameritron AL881 vs ALS600

    Subject line should say AL811.

    I understand the obvious differences between the AL811 and the ALS600 and know the ALS600 costs 2 times more. Is the tuning on the AL811 vs the benefit of the solid state and no tuning worth it? I have never owned and amp so I don't know.

    Any advice. I could probably swing the cost, but not sure I need to. As it is, I will nees to buy a QRO tuner.

    Thanks.

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    Last edited by flboy; Tue 23rd Jan 2018 at 17:43. Reason: Subject should be AL811.

  2. #2

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    I owned an 811H for years, it is still in my shack as a back up if I need it.
    It is a solid amp and was a good performer.
    The learning curve on the tuning takes a few minutes to master but that is it...
    once you get the initial setting for the bands with the antenna you use it is a snap after that, just takes a few seconds....
    record the settings and turn to them when you switch bands....on the lower bands, depending on your antenna there may be one setting for the upper portion and another for the lower section....if you are a contester, this is a pain in the rear, if you are a casual operator or rag chewer it is no problem at all


    in fact my new amp is manual tune... it is just not an issue for me...but then again, I do not contest

  3. #3

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    Thanks
    I went with the AL-811H which is 800W PEP. I couldn't see paying another $900 for the solid state unit with less power. I'll learn to tune it. I also picked up an MFJ-962D Antenna tuner to go between the antenna and PA to ensure a good match even though my antennas are resonant in the desired bands... they do edge close to 3:1 in a few places, however.

    The other thing that crossed my mind and factored in my decision is the simplicity of the AL811H. I could repair and troubleshoot it myself. Tubes are easy to replace and etc.. All common components for the most part.

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  4. #4
    K7KBN's Avatar
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    dooooooope
    Last edited by K7KBN; Wed 24th Jan 2018 at 13:48. Reason: dupe
    73
    Pat K7KBN
    Semper ubi sub ubi.

  5. #5
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    I was closing in on DXCC as a Novice back in early 1960 (max 75 watts DC INPUT, no VFO, narrow band segments....) and never really knew what my "SWR" was. THEN somebody loaned me one and it revealed a 2.5:1 at the Novice band edges on 15 meters and 5:1 in the middle. No problem: the Pi network in the transmitter IS an "antenna tuner" and it allowed me to put out around 35-40 watts RF all day without missing a beat. Of course, this was back when 15 meters was open all day, every day, 24/7.

    Most tube amplifiers can handle a 3:1 mismatch all day, and many can deal with 4:1 or, in my case, ~5:1. They'll fold back power in self-defense but if you're not overdriving them you may be surprised.
    73
    Pat K7KBN
    Semper ubi sub ubi.

  6. #6

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    congrats... have fun with it.

  7. #7

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    Recieved the AL-811H and the MFJ-962D this weekend. I am waiting on the ARB-704 and accessory cable to arrive. It was shipped separately and did not arrive Saturday. I decided on the ARB-704 to protect my IC-7300. From what I have read, not needed to work, but cheap insurance . I wanted to transmit this weekend so bad, but I will wait for it to arrive. All installed and ready to go. Looks good with the radio gear. :-)



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  8. #8

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    Amplifiers should only be used when and if all other attempts at using a more efficient antenna failed.

    You shouldn't hard wire the amplifier into the light switch - like some people.

    You should only use an amplifier when and if you need it!

    That is the purpose of the signal report - to tell you how your signal is, and if they are having problems hearing you, then you turn on the amplifier, but only to the point of where it gets the job done.
    I think this is the most abused misconception about how amplifiers works.

    Most people thinks that you have to tune it for maximum smoke, that is what makes their audio sound like crap, driving the amplifier past it's linear stage, trying to wring out every last watt.

    There is no difference in my opinion between a 600 watt and an 800 watt amplifier, as far as I am concerned,the one with 200 more watts isn't going to make one damn bit of difference in the receive of the other person - unless you are so close that you didn't need the amplifier in the first place.

    I have an ALS 600 - paid $85.00 for it, never did get around to using it - since I never got around to putting up resonant dipole antennas for every band I work. I don't like antenna tuners either - a total waste of time in my opinion.

    I did try to send my ALS 600 back to M.F.J. once, but they said that the repair would probably cost more then the amplifier, since there was so many mod's out there that they wouldn't even know where to start when it came time to trying to diagnose why it wouldn't transmit on 10 meters! I'm glad I only paid $85.00 for it, because that is all it is worth in my opinion... Where as I also bought a Dentron GLA 1000B for $85.00 and it works just fine, but I don't use it either...

    I don't like having to tune an amplifier every time I change frequencies, nor do I appreciate it when some LID comes on frequency, tuning up over my QSO... I usually chase the LIDS away and tell them to come back when they learn how to operate properly...

  9. #9

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    sixmeters, I am thrilled you were able to add so much of value to the subject matter of this thread.

  10. #10

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    Quote Originally Posted by Obed View Post
    sixmeters, I am thrilled you were able to add so much of value to the subject matter of this thread.
    Thanks Obed.. I have been a HAM a long time, experimented with many antennas and this is my first amp. Really do not need to be scolded.I am actually excited to have it.

    Won't be for surfing the airways. It is intended for nets and etc. when another S unit would make the experience better. I got the 800W so I can run 600W without maxing out the amp. From 100W to 400W is 6dB and that will make a big difference in marginal situations.

    In any case, done right and used right, a linear amp has its place in any ham shack along with the antenna tuner.

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    Last edited by flboy; Tue 30th Jan 2018 at 00:23.

  11. #11

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    flboy,

    You may already be aware but if not W8JI has some excellent amplifier documentation specifically for the 811. Most important item to remember is to only tune for about 3 or 4 seconds and wait 30 seconds between tunings to let the tubes cool. Watch your grid current. Do not exceed the readings below and you will find the tubes will last a long time. Also keep the amp clear so it will cool properly.

    Allowable AL811H meter readings:
    750 mA plate current
    200 mA grid current

    Allowable AL811 meter readings:
    550 mA plate current
    150 mA grid current

    All 811Amplifiers with 572B tubes:
    750 mA plate current

  12. #12

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    Quote Originally Posted by W8MLS View Post
    flboy,

    You may already be aware but if not W8JI has some excellent amplifier documentation specifically for the 811. Most important item to remember is to only tune for about 3 or 4 seconds and wait 30 seconds between tunings to let the tubes cool. Watch your grid current. Do not exceed the readings below and you will find the tubes will last a long time. Also keep the amp clear so it will cool properly.

    Allowable AL811H meter readings:
    750 mA plate current
    200 mA grid current

    Allowable AL811 meter readings:
    550 mA plate current
    150 mA grid current

    All 811Amplifiers with 572B tubes:
    750 mA plate current
    Thank you very much. I did get the information. I have been using the 811H for a week now and find it very easy to tune up. Glad I bought tje 1000W paint can dummy load. It comes in very handy for tuning up. I tune the antenna first with 10watts and 811H in standby, the switch to dummy load and peak up the amp, go back to coax1 and ready to go. Not very hard at all.

    I am charting in 50KC incrments so I can move around the bands by just moving to preset positions.

    Do you know if the 811H is repeatable in its tuning accuracy for this to be safe? So far, the antenna tuner appears to be very repeatable and the 811H is ussually close, but small movements don't seem to make a big difference on it for the grid... plate adjustment seems more touchy as I'd expect.

    Thanks again.

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  13. #13

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    Btw.. meant to ask... when tuned up to about 700w with about 60w exciter, plate is only about 400ma and grid is maybe 100 to 125 ma... it varies some and I expect my power meter on the MFJ tuner is not real accurate, but I was expecting to run closer to limits at what seems to be peak power out. Is this normal , do the tubes "burn in" over time and draw more? This is my first tube amplifier so asking newbie questions on real usage.

    I know how they work, amplify, and etc.. just no practical experience other than repairing some old R-390s when I was in the Army years ago and tweaking CRT's when repairing Weather Radar displays back in the day when I was a Electronics Tech and in college after my Army enlistment.

    I hope I am not doing something wrong?

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    Last edited by flboy; Tue 6th Feb 2018 at 19:14.

  14. #14

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    Quote Originally Posted by flboy View Post

    Do you know if the 811H is repeatable in its tuning accuracy for this to be safe? So far, the antenna tuner appears to be very repeatable and the 811H is ussually close, but small movements don't seem to make a big difference on it for the grid... plate adjustment seems more touchy as I'd expect.

    Yes it should be very repeatable. I would say tune up on your band and note the settings after you get it tweaked. Then put a sticker on the amp with those setting for that band. It's possible you may need a couple of load/plate settings but for the most part once you are close you will still need to tweak the load /plate for peak power output. You can increase power so long as you don't exceed grid / plate currents and you actually see power increase. After you get to peak power you will want to increase the load slightly and observe a slight drop off in power. this will ensure a clean signal.

    Once you are at peak power, more drive power will not result in anymore output power. Also if you are peaking at the lower plate/grid currents it makes me wonder if you are running on 120 instead of 240 ac input. To really get full power out of the amp you need to run on 240 volts ac. Old tubes will require more drive but if yours is a new amp you should not be anywhere near there.

    Note that increased power will get your signal out about 13 - 15 db stronger than running at 100 watts which translates into 2 S units (max) to the guy you are working. It will not let you copy the other op any better. Amps are nice but a good antenna system is better. I have a vertical on 40 meters and even with 1KW I am not going to break pile ups because my vertical has no gain. Figure out a way to get a better antenna and you will have the best of both worlds.

    Good Luck

    Good luck

  15. #15

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    W8MLS, many thanks for the information on the AL-881H. I do appreciate it. I am just getting my feet wet with the linear. Btw.. I am running on 120VAC.

    Agree 100% on the antenna. Right now, this is the best I can do. I can't put up a 40ft.+ Tower and a beam which is what I want. It is a compromise for sure.

    I did just order a West Mountain Radio Audio DSP to help some with the noise on SSB with S5's and etc.. We will see. Trying to optimize the best I can.

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    Last edited by flboy; Thu 8th Feb 2018 at 14:41.

  16. #16
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    I'd try to get that tuner off the top of the amplifier so the AL-811 can breathe. Those little rubber feet on the MFJ aren't even an inch long, and not doing the amplifier any favors.
    73
    Pat K7KBN
    Semper ubi sub ubi.

  17. #17

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    Quote Originally Posted by K7KBN View Post
    I'd try to get that tuner off the top of the amplifier so the AL-811 can breathe. Those little rubber feet on the MFJ aren't even an inch long, and not doing the amplifier any favors.
    Not sure that would do anything for me? The AL-811H top part of the cover of the amp is solid, so no convection going on there. The left side is the only vent for the fan to draw air past the tubes and out the back on the right side. The top really doesn't get that warm at all. I'll keep an eye on it.. but not sure where I would put the tuner given my space. Tx.

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    Last edited by flboy; Thu 8th Feb 2018 at 23:03.

  18. #18
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    Oops - sorry OM! I've never had an 811/811H. Most tube amplifiers I've seen rely on convection at least as much as what a small fan can provide for cooling. I'll add this to my collected wisdom which seems to be less than I remember .... (:

    73
    73
    Pat K7KBN
    Semper ubi sub ubi.

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