Re: [Elecraft] KPA 500 Fan Noise and cooling performance
Folks, this thread is drifting too far afield. Let's end the general fan discussion at this time. In the future, please resist the urge to post on OT threads like this when there are already a lot of responses in a short period, like this one. While OT threads are allowed, we ask that people resist the urge to prolong them, in the interest of improving the list signal to noise level. 73, Eric Elecraft List Manager and moderator www.elecraft.com _..._ On Jun 19, 2012, at 9:46 PM, Ron D'Eau Claire r...@cobi.biz wrote: ABSOLUTELY! My HP mini-tower has what is called a whisper quiet fan and it is very quiet. It certainly does not interfere with conversation, even when carried on across our open office between desks ten feet apart. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] KPA 500 Fan Noise and cooling performance
I put a big fan (140x140mm) on top louvers for cooling, air injected into it, and temperature drops, sin is not available a quiet fan (like computers) ... maybe in the future ... rodolfo IK4VFD - Original Message - From: donehrl...@q.com To: elecraft@mailman.qth.net Sent: Monday, June 18, 2012 8:11 PM Subject: [Elecraft] KPA 500 Fan Noise and cooling performance On 6/18/2012 4:42 AM, David Robertson wrote: ( ... a long message I won't include here where he improved amplifier cooling by tightening heatsink/right panel screws and used heatsink compound.) I operate my KPA500 with the fan speed set to #1 continuously which delays the increase in the increase in fan speed once the amplifier starts putting out power. My amplifier did not exceed 58 deg C after 10 minutes at 500 watts carrier output into a dummy load and it stabilized at about 60 degrees in a 25 degree C room. My right panel to heatsink screws (the ones under the handle) were all tight and that explains why my experience was better than was Dave's originally before he tightened his heatsink screws and added heatsink compound. I then added heatsink compound to the mating surface between my heatsink and the right side panel. There was no difference in cooling performance at all. I just wanted to know .. and now I do .. and so do you. The KPA500 fan is as quiet as any muffin fan ought to be but it was still annoying to me. That is not an amplifier fault .. it is just that I have good hearing and I prefer a *very quiet shack. For those who may be like me in that regard here is how I reduced the normal fan noise of my amplifier. In my amplifier much of the fan noise was actually coming from the sheet metal of the amplifier structure which was being excited by the vibration of the fan which is rigidly attached to the amplifier structure so that fan vibration was communicated to the structure which then resonated and amplified the fan noise. When I removed the fan and held it loosely in my hand while it was running I could feel the light high frequency 'buzz' produced by the rotating magnetic field of the fan and also, crucially, the lower frequency throb caused by a slight weight imbalance in the rotor. I used a small piece of sticky pad (normally used to mount components to a chassis, etc) and placed this very small weight at various points on the rotor blades until, by trial and error, found the 'sweet' spot which resulted in greatly reduced throb. That reduced fan noise considerably. Then, to reduce transmission of fan vibration to the amplifier structure even further, I mounted the fan loosely to the back of the amplifier using soft quarter-inch cushions between the fan and the amplifier. I used light wire to do the actual attachment instead of the long screws that are standard. The overall effect is considerably less fan noise and I am very happy about that. The fan mounting is fragile and not to be recommended if the amplifier is to be moved very much but in my installation it is just fine. By the way, I carefully compared cooling performance before and after the fan mounting modification and found no difference at all. I also noticed during my testing that the direction of airflow makes no difference. Don K7FJ __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Nessun virus nel messaggio in arrivo. Controllato da AVG - www.avg.com Versione: 9.0.930 / Database dei virus: 2433.1.1/5079 - Data di rilascio: 06/19/12 08:49:00 __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] KPA 500 Fan Noise and cooling performance
Computers quiet? Obviously have not heard mine. I have tried to get after-market fans that were advertised as quiet, but no luck. Even some that others swore were much quieter. Apparently that which actually makes a fan quiet is not part of quality control. I've seen two fans of the same model number that simply don't look the same. Go figure. I've given up. Until I can go into a store and somehow listen to the exact one I'm buying, I don't believe any of the advertising. 73, Guy. On Tue, Jun 19, 2012 at 1:39 PM, rodolfo rodo...@tin.it wrote: I put a big fan (140x140mm) on top louvers for cooling, air injected into it, and temperature drops, sin is not available a quiet fan (like computers) ... maybe in the future ... rodolfo IK4VFD - Original Message - From: donehrl...@q.com To: elecraft@mailman.qth.net Sent: Monday, June 18, 2012 8:11 PM Subject: [Elecraft] KPA 500 Fan Noise and cooling performance On 6/18/2012 4:42 AM, David Robertson wrote: ( ... a long message I won't include here where he improved amplifier cooling by tightening heatsink/right panel screws and used heatsink compound.) I operate my KPA500 with the fan speed set to #1 continuously which delays the increase in the increase in fan speed once the amplifier starts putting out power. My amplifier did not exceed 58 deg C after 10 minutes at 500 watts carrier output into a dummy load and it stabilized at about 60 degrees in a 25 degree C room. My right panel to heatsink screws (the ones under the handle) were all tight and that explains why my experience was better than was Dave's originally before he tightened his heatsink screws and added heatsink compound. I then added heatsink compound to the mating surface between my heatsink and the right side panel. There was no difference in cooling performance at all. I just wanted to know .. and now I do .. and so do you. The KPA500 fan is as quiet as any muffin fan ought to be but it was still annoying to me. That is not an amplifier fault .. it is just that I have good hearing and I prefer a *very quiet shack. For those who may be like me in that regard here is how I reduced the normal fan noise of my amplifier. In my amplifier much of the fan noise was actually coming from the sheet metal of the amplifier structure which was being excited by the vibration of the fan which is rigidly attached to the amplifier structure so that fan vibration was communicated to the structure which then resonated and amplified the fan noise. When I removed the fan and held it loosely in my hand while it was running I could feel the light high frequency 'buzz' produced by the rotating magnetic field of the fan and also, crucially, the lower frequency throb caused by a slight weight imbalance in the rotor. I used a small piece of sticky pad (normally used to mount components to a chassis, etc) and placed this very small weight at various points on the rotor blades until, by trial and error, found the 'sweet' spot which resulted in greatly reduced throb. That reduced fan noise considerably. Then, to reduce transmission of fan vibration to the amplifier structure even further, I mounted the fan loosely to the back of the amplifier using soft quarter-inch cushions between the fan and the amplifier. I used light wire to do the actual attachment instead of the long screws that are standard. The overall effect is considerably less fan noise and I am very happy about that. The fan mounting is fragile and not to be recommended if the amplifier is to be moved very much but in my installation it is just fine. By the way, I carefully compared cooling performance before and after the fan mounting modification and found no difference at all. I also noticed during my testing that the direction of airflow makes no difference. Don K7FJ __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Nessun virus nel messaggio in arrivo. Controllato da AVG - www.avg.com Versione: 9.0.930 / Database dei virus: 2433.1.1/5079 - Data di rilascio: 06/19/12 08:49:00 __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net 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
Re: [Elecraft] KPA 500 Fan Noise and cooling performance
On Tue, Jun 19, 2012 at 1:26 PM, Guy Olinger K2AV olin...@bellsouth.netwrote: ...I have tried to get after-market fans that were advertised as quiet, but no luck... === Agreed. I recently built a tower computer and put in a neat-looking 18 cm. fan in the top of the case. Because it is so huge and runs at low RPM, it is a little quieter than my previous computer, and it does have the advantage of emitting an eerie red glow from its LED-illuminated clear plastic blades. However, it is just another failed experiment in my attempt to find a quiet fan. I read somewhere that Apple has a neat fan design in its newest machines. It is balanced but the blades are various different sizes, which apparently creates a spectrum of audio resonances instead of a single hum. However, I've never heard one in real life so I can't attest that it works. Tony KT0NY -- http://www.isb.edu/faculty/facultydir.aspx?ddlFaculty=352 __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] KPA 500 Fan Noise and cooling performance
Solution - the Dyson blade less fan. Hihi On Jun 19, 2012 1:41 PM, Tony Estep estept...@gmail.com wrote: On Tue, Jun 19, 2012 at 1:26 PM, Guy Olinger K2AV olin...@bellsouth.net wrote: ...I have tried to get after-market fans that were advertised as quiet, but no luck... === Agreed. I recently built a tower computer and put in a neat-looking 18 cm. fan in the top of the case. Because it is so huge and runs at low RPM, it is a little quieter than my previous computer, and it does have the advantage of emitting an eerie red glow from its LED-illuminated clear plastic blades. However, it is just another failed experiment in my attempt to find a quiet fan. I read somewhere that Apple has a neat fan design in its newest machines. It is balanced but the blades are various different sizes, which apparently creates a spectrum of audio resonances instead of a single hum. However, I've never heard one in real life so I can't attest that it works. Tony KT0NY -- http://www.isb.edu/faculty/facultydir.aspx?ddlFaculty=352 __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net 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:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] KPA 500 Fan Noise and cooling performance
My solution was to buy a Mac Mini, which is as quiet as a church mouse. 73, Scott, N9AA On 6/19/12 2:43 PM, Gerald Manthey wrote: Solution - the Dyson blade less fan. Hihi __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] KPA 500 Fan Noise and cooling performance
Has anyone every operated one of those in close proximity to an HF rig? We built such fans in College way back in the 1950's and they were a bad of an RFI generator as any Tesla coil or Van De Graaf generator in the lab! After all, they work by electrostatic discharge. Ron AC7AC -Original Message- Solution - the Dyson blade less fan. Hihi On Jun 19, 2012 1:41 PM, Tony Estep estept...@gmail.com wrote: __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] KPA 500 Fan Noise and cooling performance
I could be wrong, but I think that the Dyson bladeless fan has, in its base, a regular ol' fan, with blades. As I understand it, that fan blows air out of holes in the trailing edge of the circular airfoil. Aerodynamic effects cause a larger volume of air to be dragged through the airfoil than the fan itself is pushing through the little holes. If that's so, it ought to be no worse a generator of RFI than any other fan. 73, Wayne Conrad KF7QGA On 06/19/12 12:24, Ron D'Eau Claire wrote: Has anyone every operated one of those in close proximity to an HF rig? We built such fans in College way back in the 1950's and they were a bad of an RFI generator as any Tesla coil or Van De Graaf generator in the lab! After all, they work by electrostatic discharge. Ron AC7AC -Original Message- Solution - the Dyson blade less fan. Hihi On Jun 19, 2012 1:41 PM, Tony Estepestept...@gmail.com wrote: __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net 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:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] KPA 500 Fan Noise and cooling performance
On 6/19/2012 11:26 AM, Guy Olinger K2AV wrote: Computers quiet? Obviously have not heard mine. I have tried to get after-market fans that were advertised as quiet, but no luck. For a long time, I've been buying only top line Thinkpads (laptops), and they're pretty quiet. Back when I was buying tower computers for my office, I replaced the power supplies with Silencer models made by PC Power and Cooling. They're also very well built supplies. pcpower.com 73, Jim K9YC __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] KPA 500 Fan Noise and cooling performance
It would be interesting and perhaps not good in the shack if this were the case but these are not electrostatic. they are nothing more than a fancy venturi to amplify air flow Air enters the base of the unit through a “mixed flow impeller” a fancy name for a turbo like fan. and is forced out of a slot. The slot runs around the inside of the ring-shaped fan body, across a “aircraft wing shape” and then outward into the room. In short, it sucks air in through the base and blows it out of a very thin slot in the inside of the ring-shaped upper body drawing additional air though it. On 6/19/2012 3:24 PM, Ron D'Eau Claire wrote: Has anyone every operated one of those in close proximity to an HF rig? We built such fans in College way back in the 1950's and they were a bad of an RFI generator as any Tesla coil or Van De Graaf generator in the lab! After all, they work by electrostatic discharge. Ron AC7AC -Original Message- Solution - the Dyson blade less fan. Hihi On Jun 19, 2012 1:41 PM, Tony Estepestept...@gmail.com wrote: __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] KPA 500 Fan Noise and cooling performance
ABSOLUTELY! My HP mini-tower has what is called a whisper quiet fan and it is very quiet. It certainly does not interfere with conversation, even when carried on across our open office between desks ten feet apart. And yet, when I power down the machine at the end of the day, the sudden quiet is priceless. It's a sudden cessation of audio pressure removed the moment it stops. That background something one grows used to and learns to ignore, but it's neither desirable or pleasant. Like anything that increases stress, learning to ignore it does not mean it is no longer causing harm. 73, Ron AC7AC -Original Message- Computers quiet? Obviously have not heard mine. I have tried to get after-market fans that were advertised as quiet, but no luck. Even some that others swore were much quieter. Apparently that which actually makes a fan quiet is not part of quality control. I've seen two fans of the same model number that simply don't look the same. Go figure. I've given up. Until I can go into a store and somehow listen to the exact one I'm buying, I don't believe any of the advertising. 73, Guy. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
[Elecraft] KPA 500 Fan Noise and cooling performance
On 6/18/2012 4:42 AM, David Robertson wrote: ( ... a long message I won't include here where he improved amplifier cooling by tightening heatsink/right panel screws and used heatsink compound.) I operate my KPA500 with the fan speed set to #1 continuously which delays the increase in the increase in fan speed once the amplifier starts putting out power. My amplifier did not exceed 58 deg C after 10 minutes at 500 watts carrier output into a dummy load and it stabilized at about 60 degrees in a 25 degree C room. My right panel to heatsink screws (the ones under the handle) were all tight and that explains why my experience was better than was Dave's originally before he tightened his heatsink screws and added heatsink compound. I then added heatsink compound to the mating surface between my heatsink and the right side panel. There was no difference in cooling performance at all. I just wanted to know .. and now I do .. and so do you. The KPA500 fan is as quiet as any muffin fan ought to be but it was still annoying to me. That is not an amplifier fault .. it is just that I have good hearing and I prefer a *very quiet shack. For those who may be like me in that regard here is how I reduced the normal fan noise of my amplifier. In my amplifier much of the fan noise was actually coming from the sheet metal of the amplifier structure which was being excited by the vibration of the fan which is rigidly attached to the amplifier structure so that fan vibration was communicated to the structure which then resonated and amplified the fan noise. When I removed the fan and held it loosely in my hand while it was running I could feel the light high frequency 'buzz' produced by the rotating magnetic field of the fan and also, crucially, the lower frequency throb caused by a slight weight imbalance in the rotor. I used a small piece of sticky pad (normally used to mount components to a chassis, etc) and placed this very small weight at various points on the rotor blades until, by trial and error, found the 'sweet' spot which resulted in greatly reduced throb. That reduced fan noise considerably. Then, to reduce transmission of fan vibration to the amplifier structure even further, I mounted the fan loosely to the back of the amplifier using soft quarter-inch cushions between the fan and the amplifier. I used light wire to do the actual attachment instead of the long screws that are standard. The overall effect is considerably less fan noise and I am very happy about that. The fan mounting is fragile and not to be recommended if the amplifier is to be moved very much but in my installation it is just fine. By the way, I carefully compared cooling performance before and after the fan mounting modification and found no difference at all. I also noticed during my testing that the direction of airflow makes no difference. Don K7FJ __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
