re.: Switching Supplies
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>I also have an Astron RS35 and RS50 linear
supplies. Sometimes the magnetic hum from them drives me crazy. The little cork pads Astron puts in them to alleviate this does not help much. I keep them under the closed console on the floor. Mike WA8EBM ----- Original Message ----- I have my RS 35M on the floor also. I shorted it out once momentarily an exciting moment. The problem is that the transistor cases that you see sticking out of the back on the heat shield are at V+ level. If something like a ground braid (this was my case) touches the transistors or the 12V output terminal you have a short. I ended up finding a cardboard box and cut the top and front off and most of the sides off. What is left is a cardboard "back shield" with lots of ventilation to prevent accidental connections to the wire maze I have down there on the floor. Mike Scott - AE6WA Tarzana, CA (DM04 / near LA) K3-100 #508/ KX1 #1311 _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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Hello all,
I am using the MFJ-4125 25A switcher with my K3. I have no RF hash or birdies from the power supply at all. I find it unbelievable that popular and supposedly quality power supplies like the Astron would leave exposed transistor cases at elevated voltage above ground. The MFJ fan, which is always running, isn't whisper quiet, but not really noisy either. This switcher faired very well in the ARRL review a few years back, in fact it was one of the most quiet ones tested. Knut - AB2TC
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In reply to this post by Mike Scott-7
Here's a plug for the MFJ-4225MV which I'll be using with my K3 any day
now ... It should go well because it's small and light (I guess most switchers can make that claim though). I have not noticed any RF noise when using it with my IC-706 or alongside my now departed FT-1000. It has a fan that runs continuously. Fairly quiet but I don't like hearing fans at all. I'm thinking of doing some sort of temperature controlled mod so the fan only runs if needed. 73--Nick, WA5BDU _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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In reply to this post by ab2tc
On Tue, 2008-07-08 at 17:02, ab2tc wrote:
> Hello all, > > I am using the MFJ-4125 25A switcher with my K3. I have no RF hash or > birdies from the power supply at all. I find it unbelievable that popular > and supposedly quality power supplies like the Astron would leave exposed > transistor cases at elevated voltage above ground. The MFJ fan, which is > always running, isn't whisper quiet, but not really noisy either. This > switcher faired very well in the ARRL review a few years back, in fact it > was one of the most quiet ones tested. > > Knut - AB2TC And the cheapest of all the ones tested, as I recall. I bought it because of the price and the small size and weight. When I go on a trip I can throw it in a suitcase with the K3 and still have room left over for clothes. The only complaint I have heard about the MFJ-4125 is the fan noise. While it is definitely audible, I personally don't find it objectionable. For those who do, placing the unit under the operating table should solve the problem. Al N1AL _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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In reply to this post by ab2tc
I find the fan noise on my MFJ-4125 unacceptable.
If I ever use it again it will have to be put behind the desk. 73, Tony W7GO ab2tc wrote: > Hello all, > > I am using the MFJ-4125 25A switcher with my K3. I have no RF hash or > birdies from the power supply at all. I find it unbelievable that popular > and supposedly quality power supplies like the Astron would leave exposed > transistor cases at elevated voltage above ground. The MFJ fan, which is > always running, isn't whisper quiet, but not really noisy either. This > switcher faired very well in the ARRL review a few years back, in fact it > was one of the most quiet ones tested. > > Knut - AB2TC > > > > Mike Scott-7 wrote: > >>> I also have an Astron RS35 and RS50 linear >>> >> supplies. Sometimes the magnetic hum from them drives me crazy. The >> little >> >> cork pads Astron puts in them to alleviate this >> does not help much. I keep them under the closed console on the floor. >> Mike WA8EBM >> ----- Original Message ----- >> >> I have my RS 35M on the floor also. I shorted it out once momentarily an >> exciting moment. The problem is that the transistor cases that you see >> sticking out of the back on the heat shield are at V+ level. If something >> like a ground braid (this was my case) touches the transistors or the 12V >> output terminal you have a short. >> >> I ended up finding a cardboard box and cut the top and front off and most >> of >> the sides off. What is left is a cardboard "back shield" with lots of >> ventilation to prevent accidental connections to the wire maze I have down >> there on the floor. >> >> Mike Scott - AE6WA >> Tarzana, CA (DM04 / near LA) >> K3-100 #508/ KX1 #1311 >> >> >> _______________________________________________ >> Elecraft mailing list >> Post to: [hidden email] >> You must be a subscriber to post to the list. >> Subscriber Info (Addr. Change, sub, unsub etc.): >> http://mailman.qth.net/mailman/listinfo/elecraft >> >> Help: http://mailman.qth.net/subscribers.htm >> Elecraft web page: http://www.elecraft.com >> >> >> > > Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Switching Supplies & KRX UPS shipping notice
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the fan on the ity bitty gamma research "super Cap " supply is VERY quiet.....
and worked well for the field day K3 GOTA station.... and just got the UPS SHIPPING NOTICE for KRX3 !!!!!!!!!! bill _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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