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Author Topic: Linear Power Supply Wanted  (Read 5656 times)
N4DSP
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Posts: 124




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« on: December 24, 2013, 11:08:47 AM »

The great majority of power supplies being manufactured are the switching type. Besides the Astron RS-35M who else manufactures linear power supplies?

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W8JX
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« Reply #1 on: December 24, 2013, 07:35:06 PM »

The great majority of power supplies being manufactured are the switching type. Besides the Astron RS-35M who else manufactures linear power supplies?



The linear supply is a dying breed. A well designed switcher is superior and less sensitive to input voltage as well. It weighs less and is far more power efficient too.
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KD8MJR
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« Reply #2 on: December 24, 2013, 08:16:40 PM »

True but I have never seen a switching power supply last for a Decade but I have linear supplies that are 25 years old and going strong. 

My problems with switchers are:

1) Unreliable, capacitors at the output will always fail it's just a matter of time, less than 10 years typically.
2) can generate RF
3) Hard to repair.
4) Can fail in ways that will blow your stuff up.

BTW why they put fuses in switching power suppplies is beyond me.  I can't ever remember seeing a blown fuse, even on ones where the board was crispy and smoking.



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N0IU
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« Reply #3 on: December 25, 2013, 04:04:31 AM »

Pyramid makes linear power supplies. http://www.pyramidcaraudio.com/products/Power-Supplies

(Pay no attention to the list prices!)
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KS2G
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« Reply #4 on: December 25, 2013, 04:54:18 AM »

... I have never seen a switching power supply last for a Decade...

Come visit my shack.
I'm using an MFJ-4225MV switching supply on my HF rig that gets heavy use in contesting.
It was purchased in 2001 and has never given me any problems.

73,
Mel - KS2G
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N4DSP
Member

Posts: 124




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« Reply #5 on: December 25, 2013, 06:16:33 AM »

No Thanks. I read the eHam reviews for all their power supplies.

Besides don't care about this "Green BS". Looking for a Linear Power Supply.
Green is Liberal Propaganda.

REMEMBER SOLYNDRA.



... I have never seen a switching power supply last for a Decade...

Come visit my shack.
I'm using an MFJ-4225MV switching supply on my HF rig that gets heavy use in contesting.
It was purchased in 2001 and has never given me any problems.

73,
Mel - KS2G
« Last Edit: December 25, 2013, 06:42:46 AM by N4DSP » Logged
N4DSP
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Posts: 124




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« Reply #6 on: December 25, 2013, 07:34:18 AM »

Nice power supplies BUT my pocket is not deep enough for that amount of cash!

Pyramid makes linear power supplies. http://www.pyramidcaraudio.com/products/Power-Supplies

(Pay no attention to the list prices!)
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N0IU
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« Reply #7 on: December 25, 2013, 07:44:52 AM »

Nice power supplies BUT my pocket is not deep enough for that amount of cash!

I said PAY NO ATTENTION TO THE LIST PRICE!!!

32 Amp Adjustable Power Supply PS36KX
List Price - $408.99
Tiger Direct price - $157.59

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PA1ZP
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Posts: 219




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« Reply #8 on: December 25, 2013, 07:48:03 AM »

Hi

I know about the switchers and I have not found a single one that is quiet.
Maybe the build in suplies of Hilberling is OK or the one of the FT9000 or IC7800 etc.

I know a classic transformer design is easy to repair and does have a long life expectancy.
i use the Maas 300 30 amp suply and that is the youngest one I have, it is about 15 yrs old now.
Also have a Maas 100 10 amp of 20 yrs, and a 6 amp of about 20 yrs.
Also have one of an other brand of 5 amp and it is 30+ yrs. old I got it for free, have it for 15 yrs now and is still in original condition with no troubles not even a fuse blow in all these suplies.
Never had a breakdown with these.
Only the little neon-tube light in the on/off switch lives for about 10 yrs and then slowly faints away.  

I had a 40 amp switcher of the same Maas brand (it is just a badge engenering brand) and it quit after just 5 yrs., no parts can be found etc.

So I would say why would't you go with something like the Daimond GSV3000.
It is an old design and most of them are working for many yrs now, all the bugs are out of these PSU's

73 Jos
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W8JX
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Posts: 5488




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« Reply #9 on: December 25, 2013, 08:06:45 AM »

True but I have never seen a switching power supply last for a Decade but I have linear supplies that are 25 years old and going strong. 

My problems with switchers are:

1) Unreliable, capacitors at the output will always fail it's just a matter of time, less than 10 years typically.
2) can generate RF
3) Hard to repair.
4) Can fail in ways that will blow your stuff up.

BTW why they put fuses in switching power suppplies is beyond me.  I can't ever remember seeing a blown fuse, even on ones where the board was crispy and smoking.


Thing is thought even if you replaced it every 10 years you are way ahead of curve because it costs less to replace and can easily save a few hundred dollars on electric bill in that time frame too.
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AA4HA
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« Reply #10 on: December 25, 2013, 09:14:48 AM »

I know that you mentioned the Astron RS-35M and it is a great supply. I have used linear supplies and switchers (Lambda) but I prefer the linear supply for being dead-quiet in generating RFI. The only way to get better is to use a battery instead of a power supply.

Every switching supply I have ever used has been a hash-generator. In part of my career I was doing the FCC compliance engineering on electronics products and every time it was the switching supply that forced me to go back and rework a design to get rid of the conducted and radiated emissions under Part 15 testing.
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Ms. Tisha Hayes, AA4HA
Lookout Mountain, Alabama
N4DSP
Member

Posts: 124




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« Reply #11 on: December 25, 2013, 09:51:35 AM »

The reviews on eHam for this power supply are comparable to
the MFJ supplies! But thanks anyways.

I said PAY NO ATTENTION TO THE LIST PRICE!!!

32 Amp Adjustable Power Supply PS36KX
List Price - $408.99
Tiger Direct price - $157.59


[/quote]
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N4DSP
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Posts: 124




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« Reply #12 on: December 25, 2013, 10:00:19 AM »

Thanks Tisha.

I know that you mentioned the Astron RS-35M and it is a great supply. I have used linear supplies and switchers (Lambda) but I prefer the linear supply for being dead-quiet in generating RFI. The only way to get better is to use a battery instead of a power supply.

Every switching supply I have ever used has been a hash-generator. In part of my career I was doing the FCC compliance engineering on electronics products and every time it was the switching supply that forced me to go back and rework a design to get rid of the conducted and radiated emissions under Part 15 testing.
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W8JX
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Posts: 5488




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« Reply #13 on: December 26, 2013, 07:53:22 AM »

Every switching supply I have ever used has been a hash-generator. In part of my career I was doing the FCC compliance engineering on electronics products and every time it was the switching supply that forced me to go back and rework a design to get rid of the conducted and radiated emissions under Part 15 testing.

Funny thing is we live in a switching supply world be it your phone chargers, HDTV's, blue ray players to name a few are powered by them today. trying to hang on to old boat anchor linear supplies is like trying to hang on to 14 year old XP that will no longer be supported in a few months.
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KD8MJR
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Posts: 2081




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« Reply #14 on: December 26, 2013, 10:35:37 AM »

Funny thing is we live in a switching supply world be it your phone chargers, HDTV's, blue ray players to name a few are powered by them today. trying to hang on to old boat anchor linear supplies is like trying to hang on to 14 year old XP that will no longer be supported in a few months.

Linear power supplies will never go away!  They are just to easy to build and they meet one major requirement, Reliability!

If you repair a switcher it's kind of frightening to realize that the only thing standing between your Radio being Fed 300Vdc versus 13.8Vdc is a $5 Chinese IC and a Zener diode, either of which faulting can cause big problems.

BTW someone said switchers handle large input voltages.  Yes that's true but they also have no form of input isolation. You get a lot of isolation when your going through a nice beefy transformer.

I remember when I was learning about how to repair switchers that the guy explaining their operation to me said from an engineering stand point its like balancing a Fridge on a mop stick.  It typically requires ten years of SPS experience before an engineer can design a proper low noise reliable switching supply.
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