Your First Power Supply – Linear or Switching?

Posted on September 15, 2021

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Are you trying to choose between a linear and switching power supply for a new radio? There are several other factors to consider beyond linear vs. switching. However, for this video I wanted to keep it focused so that anyone struggling would be able to answer the big question first.

Pictured in the video:
Astron 35m – The new version with powerpoles was just released. Looks great.

19 thoughts on “Your First Power Supply – Linear or Switching?”

  1. Another pro for linear supplies like the Astron you have there is repairability.
    Because linear supplies are fairly simple their repairs can also be pretty simple.
    Unless you melt down the transformer in one of those supplies you will probably be able to repair it quickly and cheaply.
    Cheers.

  2. Money, size and weight were and are a big deal so we bought a Samlex 1235m, based on recommendations made on other videos. Still your recommendations have me thinking. How hot does that Astron get when running all day?

  3. Astron switching power supplies are also very good. MFJ not so much. In addition to Astron, there are other brands that are good too.

  5. I chose a 20ah lifepo4 battery. And a solar panel.
    If I've got mains power, cell phone.
    Why even, power supply?

  6. I was using switching power supplies before switching power supplies were cool, early 1990s, and the switching supply I used then and still use is a Lambda switching power supply rated at 48 amps. I almost completely attenuated the RF hash noise by brute forcing ferrite beads at the output of the supply to where the noise was just above the natural noise floor of the band I was working, 10 Meters in this case, and arguably the least noisy of the HF bands. Don't let the EMI noise scare you away from using switching power supplies.

  7. I've got a VS-35M (same except variable voltage) for as long as I've been a ham.

    I was first licensed in the 70's. I've had to change a pass transistor once and it keeps on ticking.

    Had a switching supply when they first came out. Couldn't use 40 meter because of a whirling zero beat sounding rfi. They're better now. Still have my 35A and got a Astron 70 amp for my amps. A linear supply for my linear's

  8. I just use an old PC power supply that provides 36 amperes for my radio equipment testing and setup. I do transmit CB sometimes. But I am not licensed. I repair, modify, upgrade, make antennas, make manual tuners, make amplifiers, setup stations, and setup repeaters. But without a license, CB is the only transmitter I have and it is used seldom.

  12. I just heard you say the name of this channel, "
    Transmitting Until Robots Replace Us" (LOL) and I already love this channel. Okay – Subscribed & Notification All. (still LOL over the channel name ; )

  13. Linears are not completely quet. Both Astrons I have, hum. The smaller ones also hum.
    And need to mention crazy high magnetic field within 3 feet of any linear supply. Keep Away from them when operatiing! Especially with heart problems, pacemaker, etc. Not good. I measured magnetic field intensity, much much higher than maximum allowed within 3 feet or closer, any supply 20 amp or higher, keep away, use long power cable, 6 foot+

  14. Great presentation and very informative video. Astron is a great company and it’s what I prefer on my test bench and radio station.

  18. In general – a good idea for a switching supply would be a GO box, provided you didn't restrict the air flow by buring it in a mas of cables and/or panels.

    Specifics – I've always looked at MFJ with a cautious eye. Their quality control has gotten better, and they make some popular equipment lime the Versa Tuner and 259 (antenna analyzer). I've not heard much about the switching supply, so no news is good news (?).

    The Astron linear and switching supplies are workhorses, and I've only had one RS-35 fail on me when transmitting on an HF rig. A capacitor and voltage regulator replacment fixed that and havr not had problems since. Also, I've not seen a problem with their switching supplies. Their fans are quiet, and no hash on the RF.

    What you presented is a good foundation and understanding the difference between the two types. I look forward to seeing more of your videos.

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