Looking for an Alternative to ALS-500 Mobile Amp

Discussion in 'Mobile Radio Systems' started by N4UP, Aug 7, 2018.

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  1. N4UP

    N4UP Premium Subscriber QRZ Page

    Does anyone know of any good quality and in production amp suitable for mobile HF operation?

    I am currently using the ALS-500 with remote head. Looking for an alternative.

    I know Tokyo Hy-Power used to make the HL-450B but is no longer in production.

    I know of the Elecraft KPA-500 but it looks like it has an internal AC power supply not a DC one.

    Any ideas or suggestions would be appreciated.
  2. W5DXP

    W5DXP Ham Member QRZ Page

    Here's what I use:

  3. K0BG

    K0BG Platinum Subscriber Platinum Subscriber QRZ Page

    You have ONE choice—the ALS-500.

    The SG500 has been out of production for a few years, and regardless of the finals (MRF454 or 2SC2290), there are no direct replacement finals, identical numbers notwithstanding.

    Tokyo High-power is defunct as noted, and their finals are (were actually) proprietary, and fining them is almost nonobtainium.

    Dishtronix was going to have one, as was CJ, but both are stillborn.

    The ALS-500 is not a 500 watt amplifier, although you can drive it almost to that level. But if you do, you'll burn a few swamping resistors, and then the finals. Thankfully, finals are still available for it, and MFJ can fix them if you can't. Driven respectively, with about 400 PEP output, and the amplifier will run for thousands of hours with out a hiccup.

    If you want the ALS-500 to be truly automatic, without all of the extra junk MFJ requires you to buy, then buy a Bandmaster IV from Array Solutions (≈$229). A bit of connector wiring (including the ability to read a poorly-done MFJ schematic), and you can fully automate the ALS-500. What you end up with, is almost the same seamless integration that the SG500 offered. Oh! And if you want to get the most out of the ALS-500 (or any other mobile amplifier), over wire the power feed size (#4 minimum), and DO NOT use the chassis for a ground return!
    N4UP likes this.
  4. N4UP

    N4UP Premium Subscriber QRZ Page

    Thank you. That is as I feared. I am always looking for ways to improve my mobile setup, thus the post.

    I do have over 19,000 QSOs in the log from my ALS-500-MR mobile setup in three years of running counties. I typically run the amp at 200-400 watts mostly CW. I do not use the chassis for a ground return. I am happy using the ALS remote head for on-off and band-switching. I have the remote head mounted on my auto-desk along with the radio and accessories. The auto-desk is strapped to the passenger seat. The amp sits on the floor behind the passenger seat.

    I have a spare ALS-500M which I am about to swap for the original so I can see about fixing the sticky antenna relay on the original ALS-500M.

    In any event, I will stick with the ALS-500M. Thanks.
  5. W5DXP

    W5DXP Ham Member QRZ Page

    Sorry, I didn't know that. They still advertise it on the SGC web page.


    One has to try to order one to find it's out of production.
  6. K0BG

    K0BG Platinum Subscriber Platinum Subscriber QRZ Page

    Cecil, they're a shell of their former self. Pam tried to keep the business up and running for several years after Pierre died, but ended up selling the business to their chief engineer. It has languished ever since, and I sort of suspect it is due to a lack of financing.

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