Pages: [1] 2   Go Down

Author Topic: curious! switcher vs linear power supply? what you use and why?  (Read 637 times)

VE7REN

  • Member
  • Posts: 701
curious! switcher vs linear power supply? what you use and why?
« on: November 13, 2022, 10:18:52 AM »

pondering what most people use in the shack? size,weight power consumption  with a linear. i own both,but prefer a switcher,although the linear is easy to repair. 50 amp astron linear ,and a ss-30m ap switcher are used here,along with a couple samlex switchers in the shop. what are you using and why? for me ,i like the compactness and less power consumption of the switcher.
Logged

AK5B

  • Member
  • Posts: 137
    • homeURL
Re: curious! switcher vs linear power supply? what you use and why?
« Reply #1 on: November 13, 2022, 10:35:18 AM »

Most switchers generate RFI, my old Astron was terrible in that regard.  Once I went back to a linear supply all was and is well now.

73,

Jeff, AK5B
Logged

K6SDW

  • Posts: 527
    • HomeURL
Re: curious! switcher vs linear power supply? what you use and why?
« Reply #2 on: November 13, 2022, 10:56:16 AM »

I prefer switching supplies, small and light weight compared to a linear supply....I've done lotsa testing on my MFJ-4230 (which fits in my hand) and MFJ-4225 switchers and no birdies detected. Fan noise is another topic of discussion.

I don't have any issues with linear supplies, if I find a good deal on one and have the room, I'll buy it.

GL/73
Logged

AA4PB

  • Member
  • Posts: 15504
Re: curious! switcher vs linear power supply? what you use and why?
« Reply #3 on: November 13, 2022, 11:26:09 AM »

If it's for a fixed station where size and weight are of little concern then I'd use a linear supply. If it's to be used portable, where size and weight are a concern, then I'd use a switching supply.
Logged
Bob  AA4PB
Garrisonville, VA

VE7REN

  • Member
  • Posts: 701
Re: curious! switcher vs linear power supply? what you use and why?
« Reply #4 on: November 13, 2022, 03:09:01 PM »

interesting replies. thanks guys.

i dont notice ANY noise from my switchers. my older ss-50 astron developed noise on 75/80 meter,but no where else. the samlex are rock solid and clean,and so are my NEWER version astron ss-30m-ap. the fans on the astron have come a long ways too,as they are whisper quiet. the samlex only comes on after some usage in higher demand,and are noticable,but there is a fan mod available online for this. i think the linears are just to bib,and very expensive. if a person takes care of his gear and has adequate cooling and no animal hair,it will be interesting to see the longevity of the switcher vs the linear.
Logged

N5CM

  • Member
  • Posts: 895
Re: curious! switcher vs linear power supply? what you use and why?
« Reply #5 on: November 13, 2022, 04:39:25 PM »

In the shack, I use linear supplies.  As you mentioned, the are reasonably easy to repair if they break, and they're RF quiet.

I got tired of lugging a 30-amp linear supply out for Field Day and other "portable" operations, so after reading lots of reviews and threads on the subject over a spread of a couple of years, I bit the bullet and bought a Samlex SEC-1235M.  After three marathon field day efforts, some POTA activations, and a few other trips, I can say that the 1235M is RF quiet and has plenty of headroom for my 100-watt portable station and accessories.  I am pleased with the performance of the Samlex.
Logged

AI5BC

  • Posts: 456
    • HomeURL
Re: curious! switcher vs linear power supply? what you use and why?
« Reply #6 on: November 13, 2022, 04:46:36 PM »

Most switchers generate RFI,
Not if you know what to buy. The switchers are less expensive and can actually deliver their rated current.
Logged

SWMAN

  • Posts: 2117
    • HomeURL
Re: curious! switcher vs linear power supply? what you use and why?
« Reply #7 on: November 13, 2022, 06:39:50 PM »

 I use an Astron SS-30m. It is 21 years old, light and very reliable. I get no RFI anywhere that I have ever heard on any bands. I bought it because my local Texas Towers recommended it at the time. If it ever died I would buy another one for sure.
Logged

K4WH

  • Member
  • Posts: 109
Re: curious! switcher vs linear power supply? what you use and why?
« Reply #8 on: November 13, 2022, 07:18:34 PM »


Own a Alinco 330 MVT SS supply, got it as part of a used rig I purchased.  Worked fine seems to have no RFI. 

That being said I use daily a 70 amp Astron with the meters and front controls, and a 35 amp Astro packed away for now.

Just like the old pig iron supplies. 
Logged

G8FXC

  • Member
  • Posts: 533
Re: curious! switcher vs linear power supply? what you use and why?
« Reply #9 on: November 14, 2022, 12:02:38 AM »

Following a long, and very painful, thread on another forum, I've just replaced a pair of linear supplies with a single high output Astron switcher...

A lady ham had an FTdx101D - just a few weeks old - which had been completely destroyed by a power surge. Yaesu were refusing to repair under warranty because the damage was done by an external fault and the repair estimate was effectively the price of a new radio. This got me thinking about the risk to my own radio and an inspection of the circuit diagrams for my linear PSUs showed that they offered no protection against such an event. Most PSUs claim to have protection circuits in them, but look in detail and you'll see that in many cases the thing that's being protected is the PSU, not the load!

I bought an Astron 50A SMPSU to replace my two linears. It has crowbar surge protection, so the radios should be pretty safe. I've scanned the HF bands with my SDR with the PSU both on and off and there is no obvious RFI. I'm very happy with it.

Not many PSUs on the market have proper surge protection for the load - check yours. Without it, you could be faced with a very large repair bill... Linear PSUs are the worst culprits - the basic design has not changed in forty years. A transformer and rectifiers produce unregulated power at around 25v and three or four big power transistors bring that down to a nice smooth 13.8V - but the most common failure mode for those big power transistors is short-circuit - feeding that unregulated 25V straight into your radio. The PSU needs a crowbar and most don't have it.

Martin (G8FXC)
Logged

G4AON

  • Member
  • Posts: 2178
Re: curious! switcher vs linear power supply? what you use and why?
« Reply #10 on: November 14, 2022, 02:09:44 AM »

I use both, a 35A linear (Racal ex military with crowbar) and SEC-1235G in the shack. With both, I also use a "BOB" protection board with each of my shack radios, I just don't trust any power supply. The BOB project was in our RadCom magazine and is described by the author here:
https://gm4wzg.co.uk/wp/home/projects/bob/

When operating portable with a generator, I use a switching supply, a linear one just adds weight to my kit bag.

None of my switching supplies generate noise that I can detect.

I have experienced two linear supply failures, one was a cheap bench supply used in the shack to power a 10 Watt radio, fortunately I had retro fitted a crowbar and it saved the radio. The other was an audio amplifier that blew when it's linear supply failed, it was replaced under warranty and the new amp used a switching supply.

73 Dave
Logged

KT4WO

  • Member
  • Posts: 425
    • homeURL
Re: curious! switcher vs linear power supply? what you use and why?
« Reply #11 on: November 14, 2022, 02:13:37 AM »

I have 3 SMPS- Samlex, Astron and Kenwood.

ALL have RFI issues at or below 80M. Some are worse that others.
160M and 630M are unusable due to RFI.

My RS-70 hums along, for 25 years now, NO RFI.

YMMV
Logged

W1SPS

  • Member
  • Posts: 40
    • HomeURL
Re: curious! switcher vs linear power supply? what you use and why?
« Reply #12 on: November 14, 2022, 02:30:06 AM »

I have a Agilent (HP) 6032A power supply. I got it for free when a place I used to work was liquidating unused equipment. It's always worked well and has bee RF quiet for me.

73
Rich
W1SPS
Logged

NA4IT

  • Member
  • Posts: 363
    • HomeURL
Re: curious! switcher vs linear power supply? what you use and why?
« Reply #13 on: November 14, 2022, 05:12:39 AM »

Shack is powered with a 12V / 150AH UPS Battery, and a IOTA 30 amp supply / charger from Cascade Audio.
The IOTA supply is an Recreational Vehicle type supply / charger and have good RF shielding.
The DC voltage stays near 13.5V at all times, and when AC fails, there is NO loss of DC.

Logged

W9FIB

  • Member
  • Posts: 3501
    • HomeURL
Re: curious! switcher vs linear power supply? what you use and why?
« Reply #14 on: November 14, 2022, 05:44:56 AM »

I also learned the value of a switcher with good crowbar protection the hard way. The linear supply had a pass transistor short delivering almost 36 volts to my Icom. Needless to say it was fried.

I now use battery in the shack and a switcher when portable. Similar set up as NA4IT.
Logged
73, Stan
Travelling the world one signal at a time.
Pages: [1] 2   Go Up