[Elecraft] Power Supplies

amsctalx at comcast.net amsctalx at comcast.net
Sun May 6 20:02:29 EDT 2012 

Most of the answer's to Fred's questions can be found on the company's website, but... 

- Yes, it's a switching design 
- The feet/tabs/protrusions are metal. These are provided so as to allow the user (installer?) to bolt them into a cabinet or onto a desk. There are adhesive rubber feet that are shipped with the supply. 

As for the entire switching/linear debate... 

I've used both over the years. I currently have an older (linear) Agilent supply in the shack which was the primary DC supply, as I am disinclined to use hobby supplies of any type. The Bulldog is, even when compared to professional gear, quieter, the output looks the same on a scope, I haven't heard it on my radio(s) yet and it emits much less waste heat than any linear supply I have ever come in contact with. The waste heat issue alone is one of my primary motivations for installing a switching supply, and is an important consideration in a number of commercial systems. High-quality switching supplies offering high "up-time" are common-place today in many mission-critical applications. 

Also, aside from the highest-quality, professional linear supplies, I have personally witnessed fewer transformer delaminations and filter capacitor problems from switching supplies. Yes, there are plenty of "bad" switching supplies out there, but then are "bad" linear supplies as well. 

I guess I just find it odd that several responses promote a brand of linear supply that has webpages devoted to address a myriad of shortcomings, and yet this supply is met with (in my opinion) excessive skepticism, primarily on the basis of it's "switching" design. 


Mike Alexander - N8MSA 

amsctalx at comcast.net 

----- Original Message -----
From: "Ron D'Eau Claire" <ron at cobi.biz> 
To: elecraft at mailman.qth.net 
Sent: Sunday, May 6, 2012 7:15:26 PM 
Subject: Re: [Elecraft] Power Supplies 

Good questions, Fred! From their dimensions I'm guessing they are switchers. I could not find the info either. 

They look like they are designed to go into an equipment rack, not on a desk top. But I bet you could put rubber feet on those tabs easily enough. 

Color me old fashioned (I still like spending an afternoon on a horse or pounding brass with a straight key), but I avoid switchers no matter how much people claim they are quiet and I also avoid fans at every opportunity. 

I have several Astrons, not because they fail, but because they provide quiet (electrically and acoustically) power and redundancy. Should one ever fail, the other can keep the equipment humming, even if at slightly reduced output power. 

Ron AC7AC 

-----Original Message----- 
From: elecraft-bounces at mailman.qth.net [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Fred Townsend 
Sent: Sunday, May 06, 2012 10:56 AM 
To: amsctalx at comcast.net; elecraft at mailman.qth.net 
Subject: Re: [Elecraft] Power Supplies 

Hi Mike: 
Thank you for sharing about the Bulldog supplies. I have never heard of them before. My first reaction to the pictures is sooo ugly only its mother would love it. The spec sheets are clear but leave out a few things. Maybe you know. 

If it is a switcher what is its noise specification? 
The mounting tabs look like they would scratch the desktop. Are there rubber feet? 
Where are the power pole connectors? I guess you would run it with a Rigrunner. 
I didn't see any mention of certifications. UL? CE Mark? 
I like to buy American. Where are these made? 

73 
Fred, AE6QL 

-----Original Message----- 
From: elecraft-bounces at mailman.qth.net [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of amsctalx at comcast.net 
Sent: Sunday, May 06, 2012 9:22 AM 
To: elecraft at mailman.qth.net 
Subject: Re: [Elecraft] Power Supplies 

I recently purchased a Bulldog RDC-55 55A power supply from Rivergate Distributing. It's compact, runs cool, is very quiet, looks good on an oscilloscope and was designed to be used in a high-RF environment. I cannot honestly state that I have been running it for twenty years without a problem, but those that have seem to find them trouble-free. 

I think it's a shame that more people don't know about them. .. 

http://www.rivergatedist.com/PowerSupply.htm 


Mike Alexander - N8MSA 

amsctalx at comcast.net 

----- Original Message ----- 

On 5/6/2012 6:12 AM, mikefurrey at att.net wrote: 
Good Morning Ya’ll 

This morning my Astron SS-30M (used regularly for 15 years) went south in a puff of smoke and voltage on the meter was fluctuating around 10VDC. No damage to the K3. WHEW! 
I pulled out my Astron VS-50M (haven’t used in 15 years) and its voltage was also fluctuating a bit (maybe needs to reform caps?) (I’ll try it later on a ... should I say ... a radio I will not worry about too much ... or build a load for it). At a local swapfest last weekend a seller had several Astron power supplies that he was selling as parts units. He commented that they were unreliable. 

That being said, what are the groups recommendations for a power supply? 

73, Mike WA5POK ______________________________________________________________ 
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