Pro Audio Engineering KX3 Heatsink Installation Method Comparison
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- Опубликовано: 10 авг 2014
- KF5JNU and KF7IJZ compare two Elecraft KX-3s to ascertain a real-world performance level of the Pro Audio Enginering PAE-Kx31 Heat Sink. KF5JNU's radio had the heat sink installed by thermally bonding the PA transistors inside the KX3 case to the case, removing the finish from the outside of the case, and then thermally bonding the heat sink to the outside of the case. The KF7IJZ unit was stock for our first test. For our second test, we install the heat sink without doing any thermal bonding. Our results surprised us!
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Really glad I watched this video nearly 10 years later! I'll bypass the thermal compound! :)
Thank God I decided to check your video first! I was just about ready to install my Pro Audio Kx32 heat sinks on both my KX3s and was worried whether it was worth it to take out the air dryer and scrape and apply the thermo paste etc. ( version three according to Pro Adio's instruction manual. ) And it was nice that the Side KX panels and cover fit right under this heat sink.
73's
AF5LQ
Thank you so much for this video. Happy to not feel that I was missing performance by not doing the full grind and paste method.
Our latest test compares the performance of the various installation methods of the Pro Audio Engineering PAE-Kx31 KX3 heat sink. Our results were quite surprising!
Thanks for taking the time for this side by side test. This confirms that I should see about getting this heatsink for my KX3 - SN 0065
clipdan Really? For a few degrees? Not me.
In the next test I recommend PSK or data mode ... your test will go a lot faster. I could only get a couple CQ's and two QSO's on PSK before the heatsink running 5w. With the heat sink I run 10w with no issues.
Nice testing guys! In general if the screws are tightened well and all surfaces are flat and mate well, the heatsink compound is a small improvement. This is not always the case, so the thermal compound can also be viewed as performance insurance.
The amount of heat dissipated by the output FETs varies band-by-band at any given output level due to PA stage efficiency differences. You happened to choose 20M, the band on which the KX3 has the highest PA efficiency, so each PA FET is dissipating around 8 watts of heat at the 10 watt output level. The suggested optimum technique option 3 we describe in our manual is designed to ensure best performance in the worst-case, which is 6M where each FET can dissipate over 12 watts, and to a slightly less extent 10M.
In addition, I have seen some variation between KX3s in terms of PA efficiency which can affect the test results when comparing two units. Thanks for showing that the heatsink works well in either installation mode!
Howie - WA4PSC
www.proaudioeng.com
Given the undocumented and thus suspect quality of the thermal compound that's included with the Pro-Audio heatsink ... for customers who wish to fill the gap on the bottom of the heatsink that created by the "gap" in the coating, your best bet is to throw away the compound that's included with the heatsink and purchase a product of known quality. (Expect to pay upwards of $20 for just a tiny amount!)
Changing subjects, KX3 PA efficiency is highest on 40 m rather than 20 m.
Howard Hoyt Thanks for the comments! We plan on doing other tests, but given that 20M is the band where we expect that the most digital work is going to occur, we chose it rather than other bands. Either way, we were able to definitely demonstrate a real world cooling performance increase with a relatively small investment. AND it fits with the SideKX plates and cover to boot!
fred08830 Hi Fred,
The heatsink compound included with the Kx31 is standard zinc-oxide loaded silicone grease, the most common used in heatsinking semis. If one is really concerned with totally maximizing thermal transfer, then I agree, pay $$ for an exotic aluminum, silver or best yet diamond loaded heatsink grease. And despite it being the very most efficient, make sure you do not buy the "liquid-metal" heatsink compound for this use: it dissolves aluminum over time!
Howie - WA4PSC
I found it interesting that the time constant but not the steady state temperature changed, upon installing the heat sink.
This man is a beast! And he has a beast radio! This is the greatest video of the legendary KX3. Oh, and the yazi 817 can kiss my ass!
wonderful information video !
Think about about the life of the power transistor the thermal paste it does much better thermal connection to your heat syncs. This test is nice but I would put the thermal paste on to extend the life.
Very nice video. Good to see the two installation techniques compared It is also nice to see a well engineered heat sink get some attention.
I suspect that the use of a bench grinder to remove the coating from the KX3 case has resulted in a wavy surface. Even if that waviness is only a couple of thousandths of an inch, it results in a thicker coating of thermal paste instead of the extremely thin coating that works best. The thick coating of thermal paste performs about as well as the paint coating that Elecraft uses on the nice flat case. Some paints aren't as bad as I once thought. Data on thermal paste indicates that it should be as thin as possible and the surfaces must be machined very flat. Getting the necessary flatness is almost impossible using hand tools. See Howard's comments as well. Good stuff!
I know now that in the past, I have used too much thermal compound on my projects.
Mark - KE6BB
Mark P Thanks for the comments and you make a great point!
Nice test. Now how about also a timed to thermal shutdown test? Of course, a test comparing the various 3rd party heatsinks would also be great.
As well as a test that uses a calibrated bench power supply and a calibrated RF power meter.
+fred08830 Dude you need to shut your damn mouth!
This proves that Elecraft engineered it right the first time. Why spend the money for two degrees?
@Александр Гуров Prove it
4:57 Worlds longest armed man pushes plug into socket from behind camera!
Have y'all seen the results of the independent evaluation that was recently performed by 5B4AIY, who apparently hold degrees in Electrical Engineering and Mechanical Engineering? Based on his findings, the Pro-Audio Engineering claims that this heatsink is "best-performing" simply are not true. (This makes me wonder what other claims on the Pro-Audio website aren't true either.)
I'm not sure if my link (below) will get filtered, if it does then look in the Elecraft Reflector online archives for the post with the subject line "[KX3] A Comparative Performance Assessment (of Aftermarket KX3 Heatsinks)" which was posted early on the morning of 1 September 2014.
Reference www.ve7fmn.ca/this-is-cool/pdfs/performance_page/head-to-head.pdf
Thanks for sharing! My decision to purchase this heat sink was driven by the fact that it was endorsed by the SideKX panel folks. The link came through, and I look forward to reading it.
For the money not worth 3-4 degrees in my opinion. Rather have smaller radio.
n4ktz I can understand that unless you do a lot of digital mode work at full power and experience the drift. Elecraft also now makes a new heatsink that is much lower profile and bends under the body of the radio.
I got bored and stopped watching after 6 minutes and 20 seconds. Is there a summary of the results somewhere?
You don't know how to forward the video?
I do in fact ... but who's to say I wouldn't have missed the one bit that was worth watching if I had.
I'm guessing the one with more thermal mass is better than the slightly thicker piece of metal strapped to the PA :).
Are you sure all this is an improvement ? 2C and even 4 C is simply WORTHLESS. I am an engineer. The heath sink are WAY TOO BIG, the blade are too think for proper heat exchange. Just look at their Thermal analysis. You are better putting an increase in ventilation that doing this. Thank God I saw your video I cancelled the order. It is simply not god enough sorry. 73 VA2SOB Claude.