Linear Power Supplies, in 2021?

Discussion in 'General Technical Questions and Answers' started by KF0CSM, Feb 18, 2021.

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  1. KF0CSM

    KF0CSM Ham Member QRZ Page

    I've been thinking about having a second power supply around, and going a bit bigger this time around, because it is better to have it and not need it, than to need it and not have it....

    So I ask the question on KE0OG's weekly Youtubed live stream show. I ask about a linear power supply, even half jokingly asked about how truly terrible Pyramid is (I have a strange, terrible urge to buy a PSK-52 and potentially waste $240 just to see how awful they are), to get a general feel of the room. Both Mr. Casler and the chat room became very passionate about how great switching power supplies are, how much they have improved, how cheap and lightweight they are. Almost a general "DON'T BUY" on any linear, not even a high quality one.

    So, I ask the esteemed members of this board, what is the current state of this question? Are linear power supplies dying, are they a thing of hardcore HF purists to reduce any potential noise, are they a thing for old men who can't take to liking these new fangled switchers, are they a relic of the past? Or are they a more expensive, heavy, but valuable thing that holds its own in the market place for a good reason?

    I'm only on my way up in radio, looking to upgrade to General and head my way to more HF some day, maybe an amp some year. I see that Astron has a stellar reputation, that there are many claims that linear really is that much quieter. I don't mind a 50 pound tank sitting on my bench. I might spend the money to get a 70 amp monster and handle anything. I've already got a 25/30 A MFJ switcher that is doing well.

    So, I really am curious. Any help on this matter would be appreciated. Especially talking me out of that 52 amp Pyramid (even if it is just to let the smoke out and maybe have a project to fix).
     
  2. KO4HFX

    KO4HFX Ham Member QRZ Page

    I guess I qualify as an old guy but a new ham--tech and general this past fall. I have gone back and forth trying to decide what type of power supply to get. Ham equipment is in short supply and on back order everywhere. I finally have all of the pieces and parts to get up on the air, save a power supply. Had a switcher on back order but decided a quiet linear supply with no hash was best for me and changed my order to an Astron in 35 amp model. Today, I changed it to the 70 amp model. My son and his children can use it when I finished with it...
     
    WA9SVD likes this.
  3. K7JEM

    K7JEM Ham Member QRZ Page

    There are probably very few electronic devices built today with linear power supplies, for various reasons. But in the ham community, linear power supplies are still very popular, mainly because they are quiet at HF frequencies. But that is about the only reason for buying one.

    Modern switching supplies are generally very low noise, but not always. But they are always lighter and more efficient. They usually cost less money, too. And are usually more robust, and generate much less heat.

    I would not be able to recommend a linear supply today, for virtually any specific purpose. Too many really good switching supplies exist.
     
    KC6ETE likes this.
  4. AG6QR

    AG6QR Premium Subscriber QRZ Page

    When size, weight, or power consumption are important, switchers are the obvious choice. But under the desk at my shack, size and weight are irrelevant. Power consumption is small enough to not be a primary concern.

    Linear supplies emit no RF noise, are long-lived when used well below their capacity, and if needed, may be easily repaired with simple techniques and common parts.

    Sometimes, a linear supply is so good at what it does that a switcher is not an improvement.
     
    WA9SVD, KB0MNM and W9RLG like this.
  5. PA5COR

    PA5COR Ham Member QRZ Page

    I bought a new 30 amp switcher with digital LCD voltage and amp meter, is absolute quiet, no peep over the bands and is used for the FT991A with max 18 amps.
    cost 85 euro, 2 years full warranty as well.
    Nissei NS 2230D.
    Cheap and cheerfull.
     
  6. G8FXC

    G8FXC XML Subscriber QRZ Page

    Hmmm, I'm not sure that "Cheap and cheerful" is a good recommendation for a PSU that you have connected to a radio costing over £1000! This is not a criticism of the Nissei - I know nothing about it - but personally, I would not cut corners on a PSU - there is scope for a component failure to fry the attached radio doing thousands of pounds worth of damage!

    Martin
     
  7. KD8DEY

    KD8DEY Ham Member QRZ Page

    If there wasnt still a demand for them, Then Astron would have probably stopped making them by now, and just offered surplus inventory for repair parts....
    Ymmv
     
    KB0MNM likes this.
  8. K5DH

    K5DH Ham Member QRZ Page

    I've been using the same Astron RS-35M to power my station since I bought it new in 1983. I've abused it heavily, and the only thing I've ever had to fix was a failed on/off switch about 20 years ago. Otherwise, my RS-35M has performed flawlessly. You'll be able to buy it in my estate sale when I go SK someday.

    Nice thing about an Astron supply: there's nothing inside that you can't easily troubleshoot and replace. Regulator? Pass transistors? Capacitors? You can buy 'em from Mouser or Digi-key.
     
    W9FL, AG5CK and VE3WF like this.
  9. WA3GWK

    WA3GWK XML Subscriber QRZ Page

    I'm currently using an Astron RS 35A which I've had for years with no issues. I would like to have a backup PS and have been following the linear vs digital discussions. My primary concerns with digital are noise and fail safe features with are not always discernable from the product descriptions.
     
  10. VE4AJM

    VE4AJM Ham Member QRZ Page

    Another vote for the Astron 35. Mine is quiet, and causes no noise on the radio. I bought it because it was a good blend of price and reputation.
     

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