KPA1500 Fan Noise
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I have been following this thread with interest because I have a KPA1500 on order, and I have very limited flexibility as to where the RF deck can go compared to where I will have to sit. Don's video was very well done and a great help in understanding the realities. I know zero about thermodynamics, and so wanted only to say thanks to everyone who is contributing ideas, and to make but two comments. First, as to water cooling, I suspect it would be a huge weight penalty to get the cooling fluid everywhere it needs to be. So far as I know there is only one reciprocating engine made for aircraft that has a water jacket. (There might be others nowadays - I haven't owned an airplane for some years.) The reasons others don't are reliability, safety, complexity, and - mostly - weight. Second, isn't this largely a contest-operating issue? I believe we are still governed by the rule that we may use only that amount of power necessary for the communication. I contest too, so I'll face the problem on those occasions, but not for casual ragchews. I plan to make some graphs of when in terms of time, power, mode and band the fans on mine kick up a notch, and use it as a general operating guideline if I need to. Ted, KN1CBR Date: Sat, 2 Jun 2018 08:48:46 -0600 From: Don Butler <[hidden email]> To: Paul Baldock <[hidden email]>, "[hidden email]" <[hidden email]> Subject: Re: [Elecraft] KPA1500 Fan Noise Video posted Message-ID: <[hidden email]> Content-Type: text/plain; charset="utf-8" Paul ?. The PS noise is minimal from my point of view. The power supply fans do run continuously while the amp is switched on ?. You can hear the PS fans at the beginning and end of the video when the fan speed is set at ?0? .. all you?re hearing at that time is the PS fan ? at power down right at the end you can hear when the PS fans stop. Don, N5LZ ______________________________________________________________ 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 Message delivered to [hidden email] |
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Hello Ted,
I haven't owned an airplane in years either, 1995 when I sold my BD-4, Darn..... However, As I grow older and the ears get weaker, having to listen to fan noise mixed with SSB voice is a concern. I am an engineer of sorts and know that there are ways to control the noise from fans. Efficient vane design for lower RPM operation and still produce the required CFM. So what is the dBa of the 1500 at 0-5 levels? My ears like to hear <25 dBa noise. The noise in the Utube video WAS way above that. NOT good. Mel, K6KBE From: "Dauer, Edward" <[hidden email]> To: "[hidden email]" <[hidden email]> Sent: Saturday, June 2, 2018 2:15 PM Subject: [Elecraft] KPA1500 Fan Noise I have been following this thread with interest because I have a KPA1500 on order, and I have very limited flexibility as to where the RF deck can go compared to where I will have to sit. Don's video was very well done and a great help in understanding the realities. I know zero about thermodynamics, and so wanted only to say thanks to everyone who is contributing ideas, and to make but two comments. First, as to water cooling, I suspect it would be a huge weight penalty to get the cooling fluid everywhere it needs to be. So far as I know there is only one reciprocating engine made for aircraft that has a water jacket. (There might be others nowadays - I haven't owned an airplane for some years.) The reasons others don't are reliability, safety, complexity, and - mostly - weight. Second, isn't this largely a contest-operating issue? I believe we are still governed by the rule that we may use only that amount of power necessary for the communication. I contest too, so I'll face the problem on those occasions, but not for casual ragchews. I plan to make some graphs of when in terms of time, power, mode and band the fans on mine kick up a notch, and use it as a general operating guideline if I need to. Ted, KN1CBR Date: Sat, 2 Jun 2018 08:48:46 -0600 From: Don Butler <[hidden email]> To: Paul Baldock <[hidden email]>, "[hidden email]" <[hidden email]> Subject: Re: [Elecraft] KPA1500 Fan Noise Video posted Message-ID: <[hidden email]> Content-Type: text/plain; charset="utf-8" Paul ?. The PS noise is minimal from my point of view. The power supply fans do run continuously while the amp is switched on ?. You can hear the PS fans at the beginning and end of the video when the fan speed is set at ?0? .. all you?re hearing at that time is the PS fan ? at power down right at the end you can hear when the PS fans stop. Don, N5LZ ______________________________________________________________ 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 Message delivered to [hidden email] ______________________________________________________________ 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 Message delivered to [hidden email] |
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In reply to this post by Edward A. Dauer
Every amplifier has some level of fan noise. My new KPA1500 is seriously quieter than my former Expert 2KFA.
My Henry 2K Ultra fans were so loud that I couldn't keep it in the radio room. Luckily I had the remote version. My Harris RF-3230 (all solid state) had 8 six-inch muffin fans! It sounded like a DC-9 warming up for a takeoff. I was two rooms away from the shack and I could still hear those fans! I run my KPA1500 at 1500 Watts SSB/CW and I have never heard the fans go past setting #2. If you want to run 1500 Watts of RTTY or AM, then expect the fans to be running hard to keep the amp cool. If you want a quieter shack, put the amp in another room. ______________________________________________________________ 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 Message delivered to [hidden email] |
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In reply to this post by Edward A. Dauer
There are liquid cooling systems available for CPUs and graphics cards,
used by gamers and overclockers. Have no idea how this would compare to cooling a 1500 watt RF power amplifier but probably more analogous than an airplane engine. 73, Drew AF2Z On 06/02/18 17:09, Dauer, Edward wrote: > > I have been following this thread with interest because I have a KPA1500 on order, and I have very limited flexibility as to where the RF deck can go compared to where I will have to sit. > > Don's video was very well done and a great help in understanding the realities. > > I know zero about thermodynamics, and so wanted only to say thanks to everyone who is contributing ideas, and to make but two comments. > > First, as to water cooling, I suspect it would be a huge weight penalty to get the cooling fluid everywhere it needs to be. So far as I know there is only one reciprocating engine made for aircraft that has a water jacket. (There might be others nowadays - I haven't owned an airplane for some years.) The reasons others don't are reliability, safety, complexity, and - mostly - weight. Second, isn't this largely a contest-operating issue? I believe we are still governed by the rule that we may use only that amount of power necessary for the communication. I contest too, so I'll face the problem on those occasions, but not for casual ragchews. I plan to make some graphs of when in terms of time, power, mode and band the fans on mine kick up a notch, and use it as a general operating guideline if I need to. > > Ted, KN1CBR > > ______________________________________________________________ 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 Message delivered to [hidden email] |
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"Water cooling" has come a LONG way from the days back in the 90s when
we were machining out own water blocks from aluminum and copper, and trying to construct flow loops that didn't leak, find suitable radiators, etc. But I don't think there are any current CPU/GPU coolers on the market that would touch the heat rejection requirements of the combined LDMOS modules, assuming you could find a model that could be adapted, and somehow managed to find a way to get it attached.... You'd ALMOST HAVE to cool the copper heat spreader, since the LDMOS are I suspect soldered to it. Don't know if the heat spreader is soldered or mechanically attached to the heat sink.. It is possible that you could gang multiple large OTS CPU coolers onto the heat spreader in place of the massive heatsink. Then you'd need to figure out what you were going to do with the 1- "n" number of sets of hoses and radiators.... and 1-3 times n number of radiators in very large fans. And THEN, remember that there are other thermal loads inside the chassis... You'll still need to provided some airflow to those loads, so you'll still need case fans. Certainly and interesting and intriguing project for someone deep of pockets and most grande of huevos.... but not a trivial task certainly. I personally would not risk my $6k amp to do it... If I had one. :( 73, ______________________ Clay Autery, KY5G (318) 518-1389 On 06/03/18 08:11, Drew AF2Z wrote: > There are liquid cooling systems available for CPUs and graphics > cards, used by gamers and overclockers. Have no idea how this would > compare to cooling a 1500 watt RF power amplifier but probably more > analogous than an airplane engine. > > 73, > Drew > AF2Z > > > On 06/02/18 17:09, Dauer, Edward wrote: >> >> I have been following this thread with interest because I have a >> KPA1500 on order, and I have very limited flexibility as to where the >> RF deck can go compared to where I will have to sit. >> >> Don's video was very well done and a great help in understanding the >> realities. >> >> I know zero about thermodynamics, and so wanted only to say thanks to >> everyone who is contributing ideas, and to make but two comments. >> >> First, as to water cooling, I suspect it would be a huge weight >> penalty to get the cooling fluid everywhere it needs to be. So far >> as I know there is only one reciprocating engine made for aircraft >> that has a water jacket. (There might be others nowadays - I haven't >> owned an airplane for some years.) The reasons others don't are >> reliability, safety, complexity, and - mostly - weight. Second, >> isn't this largely a contest-operating issue? I believe we are >> still governed by the rule that we may use only that amount of power >> necessary for the communication. I contest too, so I'll face the >> problem on those occasions, but not for casual ragchews. I plan to >> make some graphs of when in terms of time, power, mode and band the >> fans on mine kick up a notch, and use it as a general operating >> guideline if I need to. >> >> Ted, KN1CBR >> >> > > ______________________________________________________________ > 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 > Message delivered to [hidden email] ______________________________________________________________ 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 Message delivered to [hidden email] |
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In reply to this post by Drew AF2Z
Roughly speaking, both an i7 CPU and a GTX 1070 GPU have power dissipation ratings 150 watts or less, making them each about an order of magnitude less than the likely dissipation in the KPA1500. I actually do like the idea of liquid cooling since it's efficient and flexible if designed properly, but it uses much more space ... the liquid tubes alone guarantee that and if you want quiet the radiator is much larger. I don't think that weight is the real issue here ... space certainly is, though. Liquid cooling for the KPA1500 would be unrealistic on a commercial basis for a small amp. But if you extract the heat via liquid cooling and transfer it to a large enough fan-cooled heat dissipator with larger and slower running fans, you can make the noise almost imperceptible. I have liquid CPU cooling on my desktop computer and I can't even hear the two CPU fans over the relatively quiet case and power supply fans. 73, Dave AB7E On 6/3/2018 6:11 AM, Drew AF2Z wrote: > There are liquid cooling systems available for CPUs and graphics > cards, used by gamers and overclockers. Have no idea how this would > compare to cooling a 1500 watt RF power amplifier but probably more > analogous than an airplane engine. > > 73, > Drew > AF2Z > > > On 06/02/18 17:09, Dauer, Edward wrote: >> >> I have been following this thread with interest because I have a >> KPA1500 on order, and I have very limited flexibility as to where the >> RF deck can go compared to where I will have to sit. >> >> Don's video was very well done and a great help in understanding the >> realities. >> >> I know zero about thermodynamics, and so wanted only to say thanks to >> everyone who is contributing ideas, and to make but two comments. >> >> First, as to water cooling, I suspect it would be a huge weight >> penalty to get the cooling fluid everywhere it needs to be. So far >> as I know there is only one reciprocating engine made for aircraft >> that has a water jacket. (There might be others nowadays - I haven't >> owned an airplane for some years.) The reasons others don't are >> reliability, safety, complexity, and - mostly - weight. Second, >> isn't this largely a contest-operating issue? I believe we are >> still governed by the rule that we may use only that amount of power >> necessary for the communication. I contest too, so I'll face the >> problem on those occasions, but not for casual ragchews. I plan to >> make some graphs of when in terms of time, power, mode and band the >> fans on mine kick up a notch, and use it as a general operating >> guideline if I need to. >> >> Ted, KN1CBR >> >> > > ______________________________________________________________ > 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 > Message delivered to [hidden email] > ______________________________________________________________ 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 Message delivered to [hidden email] |
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