Not sure how much better Arctic Silver is unless you need a heavier paste like on a CPU heatsink/fan so it doesn't slide all over the place. Thermalcote works pretty well and maximum temperature is higher.
Appears to be an interesting article Linear Audio | your tech audio resource. Unfortunately, since I chose to use surplus heatsinks I already had. I may be forced to look at some 'design compromises'.
It takes about two hours of continuous use to get up to max temperature. As mention in another thread I can easily mount the fans pictured below and control them with this thermal switch attached to one heatsink.
Digi-Key - 317-1502-ND (Manufacturer - CS703515Z)
Regards,
Dan 🙂
Yes use the fans, but fit a temperature switch, so that they stay OFF when not required.
And I'd suggest you use some type of temperature / speed controller if possible so that it runs quietly if that is all that is needed.
The speed controller might need it's own transformer and some clever anti-interference tweaks to keep the sound clean.
Oh, and a second temperature switch to either turn off the amp, or sound a KLAXON if the sink ever reaches your upper limit.
And I'd suggest you use some type of temperature / speed controller if possible so that it runs quietly if that is all that is needed.
The speed controller might need it's own transformer and some clever anti-interference tweaks to keep the sound clean.
Oh, and a second temperature switch to either turn off the amp, or sound a KLAXON if the sink ever reaches your upper limit.
I used thin mica and Arctic Silver on my F5 and it's fine. The datasheet says it is "not electrically conductive, [but] the compound is very slightly capacitive".
It fails to say that it also has "jam on toast" properties - drop anything with it applied and the sticky side always makes contact with something it shouldn't have...
It fails to say that it also has "jam on toast" properties - drop anything with it applied and the sticky side always makes contact with something it shouldn't have...
After a brief search I see the recommended thermal shut off switch for the Aleph series of amps is rated at 75C. 😱
Regards,
Dan
And that on the heatsink some distance away from the device interfaces.
How hot is worst case Tc when the switch triggers?
It would only be a requirement if you discover than your device/s run hotter than your upper limit.
How hot is worst case Tc when the switch triggers?
oops, that was not meant to imply that your sinks are not adequate.
It would only be a requirement if you discover than your device/s run hotter than your upper limit.
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Doesn't imply that the normal operating temperature of the amp is even near that number.
Imagine the amp placed in direct sunlight during summer season.
The pic i added in #15 is the thermal switch in the Aleph 0s (the word for zero in French, German and Dutchican is Nul
) Identical ones in the Forté Audio amps, i've used the same thermal switch type in any power amp i built, either glued-on or mounted with a screw.
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Doesn't imply that the normal operating temperature of the amp is even near that number.
Imagine the amp placed in direct sunlight during summer season.
The pic i added in #15 is the thermal switch in the Aleph 0s (the word for zero in French, German and Dutchican is Nul
Identical ones in the Forté Audio amps, i've used the same thermal switch type in any power amp i built, either glued-on or mounted with a screw.
From the Aleph 5 service Manual
Interesting that Nelson set his thermal safety cutout at 75C. By the time that switch hits 75C you would think everything else would be a little warm.
After all is said and done it would be very easy to add this to my amp.
http://www.digikey.ca/product-detail/en/CS707025Z/317-1524-ND/2195538
Regards,
Dan 🙂
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Just wind a few extra turns on one of the power transformers rather than use an additional transformer.
You can certainly add some kind of temperature controller but in my experience just run them at say half their normal voltage and they will be fairly quiet.
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Very nice, very expensive.
Great for folks who enjoy 100K switching cycles.
Plastic encased miniature breakers are fully insulated, can be glued to a heatsink, so no need to drill mounting holes.
Pre-wired, so no need for Fastons, and with 3000 cycles very likely outlive the amp owner, e.g. Pepi FC.
Miniature thermostats are sometimes offered by the dozen for 50 cents each.
$8.49 ARE YOU CRAZY.
I bought same thing on E-Bay for £3.00 for 10, there aren't the same bargains today but here is one for less than $5.00 http://www.ebay.co.uk/itm/Thermal-C...al_Components_Supplies_ET&hash=item46029928b0
I've got a boxfull here both 90 and 100 Deg C. If you want one I'll sent one to you for the P&P. (£2.10 GBP).
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OOOOPPPPPPSSS!!!!!!😱 Experience is the best teacher?
I purchased a new and very accurate thermometer and got some disturbing results. After four hours of heavy use my heatsinks got up to 57C which is about 38C over ambient. On a positive note I can use this amp for two to three hours and not exceed 40C. Hmmmmmm................it appears my future holds a couple of fans.
Regards,
Dan 🙁
I purchased a new and very accurate thermometer and got some disturbing results. After four hours of heavy use my heatsinks got up to 57C which is about 38C over ambient. On a positive note I can use this amp for two to three hours and not exceed 40C. Hmmmmmm................it appears my future holds a couple of fans.
Regards,
Dan 🙁
57 Degress is hot but not too hot.
Just make sure that the caps aren't getting too hot.
I've got two 50mm 12V fans running at 6V above each cap bank, almost silent and it keeps the caps cool.
I've been told that Class A will actually run COOLER in High Power Use as more power is being transferred to the speakers.
Worst case is to listen to it very quietly.
Have you tried upending it as I suggested ??
Just make sure that the caps aren't getting too hot.
I've got two 50mm 12V fans running at 6V above each cap bank, almost silent and it keeps the caps cool.
I've been told that Class A will actually run COOLER in High Power Use as more power is being transferred to the speakers.
Worst case is to listen to it very quietly.
Have you tried upending it as I suggested ??
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http://docs-europe.electrocomponents.com/webdocs/0029/0900766b80029944.pdf
You'll be amazed that most heatsinks are nearly 100% more efficient at removing heat when fitted with a small fan and nearly 100% less efficient when fitted so that the fins are horizontal in free air.
You'll be amazed that most heatsinks are nearly 100% more efficient at removing heat when fitted with a small fan and nearly 100% less efficient when fitted so that the fins are horizontal in free air.
TRUE. The genuine Alephs run a lot hotter than 57 Degrees C, closer to 78 Degrees if I remember correctly.
they have a thermalfuse of 75C if my memmory servs me correct. so it hav to be lower.
much lower. the was made to work in any part of the world.
i doubt they will work in dubai with about 50C above ambient 😀
much lower. the was made to work in any part of the world.
i doubt they will work in dubai with about 50C above ambient 😀
the F5 transitions to ClassAB in the transient peaks, if run hard.
That short period in ClassAB, repeated many times, could make the F5 dissipate more than the quiescent condition.
Yes sorry, I forgot this is an F5, not a true Class A.
It will still run cooler with the heatsink vanes mounted vertically.
It will still run cooler with the heatsink vanes mounted vertically.
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