That's not to say that they didn't try. Unlike manufacturers who only make linears, Elecraft has a vested interest in making their product line friendly to all their products and a switcher would have to pass muster against their own sensitive receiver. So, Elecraft internal standard for noise is probably much higher than in the general market place.
David G3UNA > Hello George, > > From my reading of all the replies both on and off-the-list, the main > reasons are: > > 1. it is cheaper to use linear PSU so that the price of KPA500 should be > competitive; > 2. maintenance and repair will be easier for a linear PSU; > 3. RFI is so often found in the switching PSU > > I put this question up in the reflector because I find ICPW-1, VL1000 and > TL933 are all using switching PSU. I think items 1 & 2 above have > explained the reason of using linear PSU in KPA500. > > Voltage fluctuation in the AC mains will affect the linearity of the PSU > in KPA500. However, this will not border me because the reliability of AC > power supply in Hong Kong is over 99.9%. We have never suffered from any > power interruption in the past years. > > See you all next week in Dayton. > > TNX & 73, > > > Johnny VR2XMC > > > I can not believe hams who do not want switching mode supplies in their > shack. This precludes the use of a computer in the shack. It also means no > TVs, printers, and a host of other products. There is also a false notion > that so called linear supplies do not cause RFI. Study Dirac's delta > function and you will understand why they can. > Love my two K3s > George, W6GF > > > > > One of the inviolable rules in the W6LX shack is: NO SWITCHING POWER > SUPPLIES. > > Not to make an incendiary statement, but *all* of them generate RFI. Many > people > will tell you that they've never heard RFI from their switching power > supplies, > but often it's just because they don't know what it sounds like or they > haven't > tuned across the right frequency. > > > Why raise the noise floor by even half a dB if you can help it? > > Nothing beats a old-fashioned, big, beefy, and quiet linear power supply. > > Al W6LX > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
