[Elecraft] KPA500 - linear power supply

[David Cutter]

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
>