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Thread: 3-500z based amplifiers

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  1. #1
    Join Date
    Jan 2008
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    Central Florida
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    Default 3-500z based amplifiers

    Are there any inexpensive 3-500z amps out there that are well built and reliable? Maybe a contradiction of terms. I was look at the AL-80a or 80B but the B is over 1300.00 which i do not have. SB-220 possibly but power demands are high. Suggestions?

  2. #2

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    You can sometimes find a really good SB-220 that works properly and has good tubes for about $650 or so.

    They're all over the place.

    The Drake L-4B and L-7 can often be found in the $700 to $850 range, and those can be good deals, too.

    A used AL-80B is usually less than $1K and it's a solid amplifier.

    All this assumes they haven't been abused. I'd go for a "local deal" so I could look at it and try it out before exchanging cash for hardware.

    The power demands for the SB-220 aren't very high. A 240V 10A circuit will do it, and since #14AWG wiring supports 15A just fine, almost any 240V outlet will power it. Using one on 120V is pushing it.
    What if soy milk is just regular milk introducing itself in Spanish?

  3. #3
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    I Have found out that the 120v wiring in my house is using 12 gauge wiring. And circuit breakers are all 20 Amp Do you think
    it can handle a SB-220?

  4. #4

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    Quote Originally Posted by KJ4AQU View Post
    I Have found out that the 120v wiring in my house is using 12 gauge wiring. And circuit breakers are all 20 Amp Do you think
    it can handle a SB-220?
    Probably, especially if you have nothing else plugged into that circuit.
    What if soy milk is just regular milk introducing itself in Spanish?

  5. #5
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    That Drake L-7 looks sweet. But pricey. I'll probably try to concentrate on an Al-80a or B. A single 3-500z type.

  6. #6
    Join Date
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    north central Connecticut
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    Default

    The SB-220 is nice because you have two 3-500Z tubes sharing the load, and the SB-220 is a one kW and
    doesn't push the tubes as hard as the Ameritron amp. If you back the drive to the amp down to
    50 or 60 watts, the power demand from the AC line will be a lot less.
    Remember they are getting long in the tooth and may need new filter caps and other work.

    Pete

  7. #7

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    AQU --

    IF you are on limited or fixed income (usage of words inexpensive, pricey),
    moving up to 1 kW > amplifiers may be challenging.

    IF your current antennas, tuners, station accessories, etc. were cheap purchases --
    they may not be rated for more than 200 to 300 watts RF. They would have to be replaced.

    IF you can not afford the replacement tube(s) for the HF amplifier that you want to purchase --
    you can not afford that specific amplifier.
    Amateurs already have amplifiers in closets, storage, etc. with dead tubes -- they can not afford to replace.

    NEVER buy a used amplifier without seeing it operate -- unless you are prepared to restore it $$
    Something to think about, before committing to purchases.
    Last edited by W9GB; 04-17-2012 at 01:46 AM.
    Nullius in verba

  8. #8
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    Default

    Quote Originally Posted by W9GB View Post
    AQU --

    IF you are on limited or fixed income (usage of words inexpensive, pricey),
    moving up to 1 kW > amplifiers may be challenging.

    IF your current antennas, tuners, station accessories, etc. were cheap purchases --
    they may not be rated for more than 200 to 300 watts RF. They would have to be replaced.

    IF you can not afford the replacement tube(s) for the HF amplifier that you want to purchase --
    you can not afford that specific amplifier.
    Amateurs already have amplifiers in closets, storage, etc. with dead tubes -- they can not afford to replace.

    NEVER buy a used amplifier without seeing it operate -- unless you are prepared to restore it $$
    Something to think about, before committing to purchases.
    Very True I put a lot of money into an SB-200 that I did not see tested. So for now I'll stick with an SB-200 class for now.
    or AL-811 which I currently have.

  9. #9

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    Quote Originally Posted by KJ4AQU View Post
    Are there any inexpensive 3-500z amps out there that are well built and reliable? Maybe a contradiction of terms. I was look at the AL-80a or 80B but the B is over 1300.00 which i do not have. SB-220 possibly but power demands are high. Suggestions?
     SB-220s operating on the LV tap do not much need to be operated from a 240V circuit. Operating on the LV tap only reduces output by 1.5db - or 1/4 of 1 S-unit. I can switch my SB-220 from the LV tap to the HV tap and no one at the Rx-end can consistently tell which tap its on.
    Fixing the design flubs in the SB-220 is fairly easy and doing so can save you much $$ as well as save you from grief. No matter which amplifier you purchase, remember that there is no such thing as a perfect amplifier - so be prepared to make some circuit improvements.
    Rich, AG6K, [url]www.somis.org[/url] 805-386-3734

  10. #10

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    And since the 220 is an already low IMD amp it is even better when run on SSB on the CW position. No need to reduce drive, just run a typical 100W rig and it will self limit to around 750-800W out when fully loaded.

    Carl

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