KPA500 - stacking possibilites
Locked
 
|
Now that I have received confirmation of the delivery, I need finalize where
I am going to place my new KPA500. Given a very limited desk size (ony 34 inches wide), I wonder if the K3 can be stacked on top of the KPA500. I undertand from earlier posts that there needs to be a minimum half inch clearance on top of the KPA500 for the air intake grill. Has any FTer stacked the two boxes to see if they work without generating too much heat? ..mike AI6II ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
Re: KPA500 - stacking possibilites
|
|
Just for operational convenience I'd consider stacking them the other way,
with the K3 VFO A knob at a convenient height for tuning and the amplifier above the K3. I've found some very handy open-shelving bamboo "shoe racks" at CostCo that are doing the job for me. My amplifier is about 2 inches above the K3. The rack is wide enough for a K3, P3, and another box such as a rotator controller or a US Interface Navigator. The 2nd shelf hosts a second K3 and a KPA500. The top shelf has two speakers and various junk that I gather. I've found these racks so useful that I have 5 or 6 of them. I can hold QSL boxes on them and some plastic shoe boxes that hold various projects. I have a lot of little projects and boxes. Dick, K6KR -----Original Message----- From: [hidden email] [mailto:[hidden email]] On Behalf Of ai6ii Sent: Tuesday, May 10, 2011 6:59 PM To: [hidden email] Subject: [Elecraft] KPA500 - stacking possibilites Now that I have received confirmation of the delivery, I need finalize where I am going to place my new KPA500. Given a very limited desk size (ony 34 inches wide), I wonder if the K3 can be stacked on top of the KPA500. I undertand from earlier posts that there needs to be a minimum half inch clearance on top of the KPA500 for the air intake grill. Has any FTer stacked the two boxes to see if they work without generating too much heat? ..mike AI6II ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
Re: KPA500 - stacking possibilites
|
|
Can we see some pictures of your setup?
Henk PA5KT Op 11-05-2011 4:14, Dick Dievendorff schreef: > Just for operational convenience I'd consider stacking them the other way, > with the K3 VFO A knob at a convenient height for tuning and the amplifier > above the K3. > > I've found some very handy open-shelving bamboo "shoe racks" at CostCo that > are doing the job for me. My amplifier is about 2 inches above the K3. The > rack is wide enough for a K3, P3, and another box such as a rotator > controller or a US Interface Navigator. The 2nd shelf hosts a second K3 and > a KPA500. The top shelf has two speakers and various junk that I gather. > > I've found these racks so useful that I have 5 or 6 of them. I can hold QSL > boxes on them and some plastic shoe boxes that hold various projects. I > have a lot of little projects and boxes. > > Dick, K6KR > > > -----Original Message----- > From: [hidden email] > [mailto:[hidden email]] On Behalf Of ai6ii > Sent: Tuesday, May 10, 2011 6:59 PM > To: [hidden email] > Subject: [Elecraft] KPA500 - stacking possibilites > > Now that I have received confirmation of the delivery, I need finalize where > I am going to place my new KPA500. Given a very limited desk size (ony 34 > inches wide), I wonder if the K3 can be stacked on top of the KPA500. I > undertand from earlier posts that there needs to be a minimum half inch > clearance on top of the KPA500 for the air intake grill. Has any FTer > stacked the two boxes to see if they work without generating too much heat? > > ..mike AI6II > ______________________________________________________________ -- Henk Remijn PA5KT email: [hidden email] www: www.pa5kt.com ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
Re: KPA500 - stacking possibilites
|
|
As the KPA 500 uses a linear PSU there obviously is a mains
transformer within the cabinet. I know this is a toroidal type transformer, which is good, but can we assume that placement of the Amp with respect to the K3 is non critical, for magnetic hum coupling. How immune is the K3 to this effect? Has placement of the KPA 500 w.r.t. the K3 been tested for any ill effects? 73, Deni F5VJC On 11 May 2011 07:49, Henk Remijn PA5KT <[hidden email]> wrote: > Can we see some pictures of your setup? > > Henk PA5KT > > Op 11-05-2011 4:14, Dick Dievendorff schreef: >> Just for operational convenience I'd consider stacking them the other way, >> with the K3 VFO A knob at a convenient height for tuning and the amplifier >> above the K3. >> >> I've found some very handy open-shelving bamboo "shoe racks" at CostCo that >> are doing the job for me. My amplifier is about 2 inches above the K3. The >> rack is wide enough for a K3, P3, and another box such as a rotator >> controller or a US Interface Navigator. The 2nd shelf hosts a second K3 and >> a KPA500. The top shelf has two speakers and various junk that I gather. >> >> I've found these racks so useful that I have 5 or 6 of them. I can hold QSL >> boxes on them and some plastic shoe boxes that hold various projects. I >> have a lot of little projects and boxes. >> >> Dick, K6KR >> >> >> -----Original Message----- >> From: [hidden email] >> [mailto:[hidden email]] On Behalf Of ai6ii >> Sent: Tuesday, May 10, 2011 6:59 PM >> To: [hidden email] >> Subject: [Elecraft] KPA500 - stacking possibilites >> >> Now that I have received confirmation of the delivery, I need finalize where >> I am going to place my new KPA500. Given a very limited desk size (ony 34 >> inches wide), I wonder if the K3 can be stacked on top of the KPA500. I >> undertand from earlier posts that there needs to be a minimum half inch >> clearance on top of the KPA500 for the air intake grill. Has any FTer >> stacked the two boxes to see if they work without generating too much heat? >> >> ..mike AI6II >> ______________________________________________________________ > > -- > Henk Remijn PA5KT > email: [hidden email] > www: www.pa5kt.com > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > -- 73 Deni, F5VJC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
|
|
I notice KPA500 is using a linear power supply. The technology of switching power supply is now very mature. Is there any reason why linear PSU is used instead of switching PSU in KPA500? I just think a switching PSU will make KPA500 more lighter and the linearity of the amplifier will not be affected by fluctuation in supply voltages.
A lighter KPA500 will make it more portable for Dxpedition. My questions may be discussed somewhere in the past. Any advice? TNX & 73, Johnny VR2XMC 從︰ F5vjc <[hidden email]> 收件人︰ Henk Remijn PA5KT <[hidden email]> 副本(CC)︰ [hidden email] 傳送日期︰ 2011年05月11日 (週三) 9:26 PM 主題︰ Re: [Elecraft] KPA500 - stacking possibilites As the KPA 500 uses a linear PSU there obviously is a mains transformer within the cabinet. I know this is a toroidal type transformer, which is good, but can we assume that placement of the Amp with respect to the K3 is non critical, for magnetic hum coupling. How immune is the K3 to this effect? Has placement of the KPA 500 w.r.t. the K3 been tested for any ill effects? 73, Deni F5VJC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
|
|
The unregulated linear power supply is heavier than a switcher. However, it
is also more efficient and less complex. Everything is a trade-off. Phil - AD5X ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
Re: KPA500 - linear power supply
|
|
On 05/11/2011 04:00 PM, Phil & Debbie Salas wrote:
> The unregulated linear power supply is heavier than a switcher. However, it > is also more efficient and less complex. Everything is a trade-off. It's also possible that an amp with switcher would be harder to sell. We're a conservative bunch. Jon LA4RT > > Phil - AD5X > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
Re: KPA500 - linear power supply
|
|
In reply to this post by Johnny Siu
A couple of years ago, I looked hard at the THP amps at Dayton. They were using
linear supplies as well. If I remember right, the PS voltage was 60 volts no load...and 48 volts under full power. I think there might be a cost issue here as well. Less parts for a non switching power supply...less complexity too....and field repairable as well. Lee - K0WA In our day and age it seems that Common Sense is in short supply. If you don't have any Common Sense - get some Common Sense and use it. If you can't find any Common Sense, ask for help from somebody who has some Common Sense. Is Common Sense divine? Common Sense is the image of the Creator expressing revealed truth in my mind. - John W. (Kansas) ________________________________ From: Johnny Siu <[hidden email]> To: F5vjc <[hidden email]>; Henk Remijn PA5KT <[hidden email]> Cc: "[hidden email]" <[hidden email]> Sent: Wed, May 11, 2011 8:39:10 AM Subject: [Elecraft] KPA500 - linear power supply I notice KPA500 is using a linear power supply. The technology of switching power supply is now very mature. Is there any reason why linear PSU is used instead of switching PSU in KPA500? I just think a switching PSU will make KPA500 more lighter and the linearity of the amplifier will not be affected by fluctuation in supply voltages. A lighter KPA500 will make it more portable for Dxpedition. My questions may be discussed somewhere in the past. Any advice? TNX & 73, Johnny VR2XMC 從︰ F5vjc <[hidden email]> 收件人︰ Henk Remijn PA5KT <[hidden email]> 副本(CC)︰ [hidden email] 傳送日期︰ 2011年05月11日 (週三) 9:26 PM 主題︰ Re: [Elecraft] KPA500 - stacking possibilites As the KPA 500 uses a linear PSU there obviously is a mains transformer within the cabinet. I know this is a toroidal type transformer, which is good, but can we assume that placement of the Amp with respect to the K3 is non critical, for magnetic hum coupling. How immune is the K3 to this effect? Has placement of the KPA 500 w.r.t. the K3 been tested for any ill effects? 73, Deni F5VJC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
|
|
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:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
|
|
In reply to this post by k0wa@swbell.net
Every switching supply I have ever owned eventually failed, except my
carry-around 18 amp job for porting my K3, and the current power supply in my PC, one week old after the previous failed. Most of the switchers were in PC's. I have never had a linear supply fail. Everyone is trying to make switchers light, cheaper, less components, less fan, less everything that makes one reliable. A toroid transformer's external flux is WAY down from a standard transformer. And in the strange case that you actually had it fail, you could rewind it yourself. But the weakest point in a transistor amplifier is ALWAYS going to be the transistors. Abuse the amp, and the transistors will be the first to go, if at all, not the power supply. 73, Guy. On Wed, May 11, 2011 at 11:40 AM, Lee Buller <[hidden email]> wrote: > A couple of years ago, I looked hard at the THP amps at Dayton. They were using > linear supplies as well. If I remember right, the PS voltage was 60 volts no > load...and 48 volts under full power. > > I think there might be a cost issue here as well. Less parts for a non > switching power supply...less complexity too....and field repairable as well. > > Lee - K0WA > > > In our day and age it seems that Common Sense is in short supply. If you don't > have any Common Sense - get some Common Sense and use it. If you can't find any > Common Sense, ask for help from somebody who has some Common Sense. Is Common > Sense divine? > > Common Sense is the image of the Creator expressing revealed truth in my mind. > - John W. (Kansas) > > > > > > > ________________________________ > From: Johnny Siu <[hidden email]> > To: F5vjc <[hidden email]>; Henk Remijn PA5KT <[hidden email]> > Cc: "[hidden email]" <[hidden email]> > Sent: Wed, May 11, 2011 8:39:10 AM > Subject: [Elecraft] KPA500 - linear power supply > > I notice KPA500 is using a linear power supply. The technology of switching > power supply is now very mature. Is there any reason why linear PSU is used > instead of switching PSU in KPA500? I just think a switching PSU will make > KPA500 more lighter and the linearity of the amplifier will not be affected by > fluctuation in supply voltages. > > A lighter KPA500 will make it more portable for Dxpedition. My questions may be > discussed somewhere in the past. > > Any advice? > > TNX & 73, > > > Johnny VR2XMC > > 從︰ F5vjc <[hidden email]> > 收件人︰ Henk Remijn PA5KT <[hidden email]> > 副本(CC)︰ [hidden email] > 傳送日期︰ 2011年05月11日 (週三) 9:26 PM > 主題︰ Re: [Elecraft] KPA500 - stacking possibilites > > As the KPA 500 uses a linear PSU there obviously is a mains > transformer within the cabinet. > I know this is a toroidal type transformer, which is good, but can we > assume that placement of the Amp with respect to the K3 is non > critical, for magnetic hum coupling. > > How immune is the K3 to this effect? Has placement of the KPA 500 > w.r.t. the K3 been tested for any ill effects? > > 73, Deni > F5VJC > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
Re: KPA500 - linear power supply
|
|
In reply to this post by alorona
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 --- On Wed, 5/11/11, Al Lorona <[hidden email]> wrote: From: Al Lorona <[hidden email]> Subject: Re: [Elecraft] KPA500 - linear power supply To: Date: Wednesday, May 11, 2011, 9:04 AM 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:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
Re: KPA500 - linear power supply
|
|
In reply to this post by Phil Salas
--- On Wed, 5/11/11, Phil & Debbie Salas <[hidden email]> wrote: The unregulated linear power supply is heavier than a switcher. However, it is also more efficient and less complex. Everything is a trade-off. Agreed on the heavier and less complex, but as for effieciency, it has been my experience that the linear takes more current (to charge the pwr xfmr core, regulation system, etc.) in the standby mode than does the switcher. Agree with others on the switchers being RFI generators. Not good for sensitive receivers. My supply heavier than most being a 55Ah Optima Yellow top gell cell battery with float charger. Very well filtered! Mike AC5P ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
Re: KPA500 - linear power supply
|
|
In reply to this post by Phil Salas
In addition, the unregulated analog supplies are potentially 30 to 50% less expensive than a switcher. Given standing current for class AB1, the regulation of an analog supply with a properly sized transformer supply is not an issue. 73, ... Joe, W4TV On 5/11/2011 10:00 AM, Phil & Debbie Salas wrote: > The unregulated linear power supply is heavier than a switcher. However, it > is also more efficient and less complex. Everything is a trade-off. > > Phil - AD5X > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
Re: KPA500 - linear power supply
|
|
In reply to this post by Johnny Siu
I know this is a real long shot, BUT, do any of you fortunate folks who already use the KPA500 have the instrument or capability to measure the KVA demand and power factor or phase angle of the AC input to the amp under full load output? Just curious about this and the overall efficiency of the unit. Just saw the inside photos yesterday and that big current transformer is a beauty. Mike, AC5P ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
Re: KPA500 - stacking possibilites
|
|
In reply to this post by Deni F5VJC
I have operated that way and found no effect at all.
Works here. Gary On 11 May 2011 23:26, F5vjc <[hidden email]> wrote: > As the KPA 500 uses a linear PSU there obviously is a mains > transformer within the cabinet. > I know this is a toroidal type transformer, which is good, but can we > assume that placement of the Amp with respect to the K3 is non > critical, for magnetic hum coupling. > > How immune is the K3 to this effect? Has placement of the KPA 500 > w.r.t. the K3 been tested for any ill effects? > > 73, Deni > F5VJC > > On 11 May 2011 07:49, Henk Remijn PA5KT <[hidden email]> wrote: > > Can we see some pictures of your setup? > > > > Henk PA5KT > > > > Op 11-05-2011 4:14, Dick Dievendorff schreef: > >> Just for operational convenience I'd consider stacking them the other > way, > >> with the K3 VFO A knob at a convenient height for tuning and the > amplifier > >> above the K3. > >> > >> I've found some very handy open-shelving bamboo "shoe racks" at CostCo > that > >> are doing the job for me. My amplifier is about 2 inches above the K3. > The > >> rack is wide enough for a K3, P3, and another box such as a rotator > >> controller or a US Interface Navigator. The 2nd shelf hosts a second K3 > and > >> a KPA500. The top shelf has two speakers and various junk that I > gather. > >> > >> I've found these racks so useful that I have 5 or 6 of them. I can hold > QSL > >> boxes on them and some plastic shoe boxes that hold various projects. I > >> have a lot of little projects and boxes. > >> > >> Dick, K6KR > >> > >> > >> -----Original Message----- > >> From: [hidden email] > >> [mailto:[hidden email]] On Behalf Of ai6ii > >> Sent: Tuesday, May 10, 2011 6:59 PM > >> To: [hidden email] > >> Subject: [Elecraft] KPA500 - stacking possibilites > >> > >> Now that I have received confirmation of the delivery, I need finalize > where > >> I am going to place my new KPA500. Given a very limited desk size (ony > 34 > >> inches wide), I wonder if the K3 can be stacked on top of the KPA500. I > >> undertand from earlier posts that there needs to be a minimum half inch > >> clearance on top of the KPA500 for the air intake grill. Has any FTer > >> stacked the two boxes to see if they work without generating too much > heat? > >> > >> ..mike AI6II > >> ______________________________________________________________ > > > > -- > > Henk Remijn PA5KT > > email: [hidden email] > > www: www.pa5kt.com > > > > ______________________________________________________________ > > Elecraft mailing list > > Home: http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/mmfaq.htm > > Post: mailto:[hidden email] > > > > This list hosted by: http://www.qsl.net > > Please help support this email list: http://www.qsl.net/donate.html > > > > > > -- > 73 Deni, > > F5VJC > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > -- VK4FD - Motorhome Mobile Elecraft Equipment K3 #679, KPA-500 #018 Living the dream!!! ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
|
|
In reply to this post by george fritkin
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 從︰ george fritkin <[hidden email]> 收件人︰ Elecraft Reflector <[hidden email]> 傳送日期︰ 2011年05月12日 (週四) 12:16 AM 主題︰ Re: [Elecraft] KPA500 - linear power supply 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 --- On Wed, 5/11/11, Al Lorona <[hidden email]> wrote: From: Al Lorona <[hidden email]> Subject: Re: [Elecraft] KPA500 - linear power supply To: Date: Wednesday, May 11, 2011, 9:04 AM 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:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
Re: KPA500 - linear power supply
|
|
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:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
Re: KPA500 - linear power supply
|
|
I would not be surprised to hear Eric and Wayne state that price was not
that big a consideration with regard to the power supply even though it would have been one of the considerations. My bet is that IMD performance, reliability, durability and maybe stable performance played a significant role in their final decision. I have to say that given the testing I have done here the amplifier works better than I expected. The quality I expected, but I still got a surprise with the performance. I don't find the amplifier heavy but of course a switcher would have reduced some weight but I doubt it would have provided any further benefit...ymmv 73's Gary On 12 May 2011 18:45, David Cutter <[hidden email]> wrote: > 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:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > -- VK4FD - Motorhome Mobile Elecraft Equipment K3 #679, KPA-500 #018 Living the dream!!! ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
|
|
One big issue with switching power supplies is their dynamic
performance. An SSB transmission requires the power supply to be happy with a load that randomly varies between maximum current and the resting current of the PA. If the power supply does not have good dynamic regulation, that can cause distortion. With a linear supply, the output filter capacitors have to be big enough to filter the 100 Hz or 120-Hz ripple anyway, so they automatically do a good job of smoothing out the variations due to the 300-3000Hz audio of the SSB signal. However, the filter capacitors in a switching supply can be much smaller since they only have to filter out the high-frequency ripple from the switcher. So the dynamic regulation depends on the feedback circuitry in the switching regulator. If it isn't designed in such a way as to provide low output impedance in the audio range, considerable distortion can result. Al N1AL On Thu, 2011-05-12 at 19:06 +1000, Gary Gregory wrote: > I would not be surprised to hear Eric and Wayne state that price was not > that big a consideration with regard to the power supply even though it > would have been one of the considerations. My bet is that IMD performance, > reliability, durability and maybe stable performance played a significant > role in their final decision. > > I have to say that given the testing I have done here the amplifier works > better than I expected. The quality I expected, but I still got a surprise > with the performance. > > I don't find the amplifier heavy but of course a switcher would have reduced > some weight but I doubt it would have provided any further benefit...ymmv > > 73's > Gary > > > > > > On 12 May 2011 18:45, David Cutter <[hidden email]> wrote: > > > 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:[hidden email] > > > > This list hosted by: http://www.qsl.net > > Please help support this email list: http://www.qsl.net/donate.html > > > > > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
«
Return to [QRO]
|
1 view|%1 views
| Free forum by Nabble | Edit this page |