Mica or Bergquist K10 Pads...Can't Decide!!

EchoWars · 30th March 2005, 10:16 PM

Have a Class A amp that I'm working on...the TO-3 outputs are disappating about 40W each. I've been reading and looking at specs and still can't decide whether to use regular Mica insulators with grease, or Bergquist K10 sil-pads. I love the idea of skipping the damn grease, but are the K10's good enough for the job?

Thoughts are really appreciated...

sam9 · 30th March 2005, 10:34 PM

Per the datasheet the K-10 is about as effective as mica. In actual use I've found they are easier to use than mica and conform to irregularities better. They may be slightly more vulnerable to being pierced by small metal chips, grit, etc. --- so pay attention to cleanliness.

I suspect surface flatness and correct torque will have a bigger impact than mica vs k-10. I don't think either will make a significant difference in the amount of heat dissapated relative to the other.

AKSA · 31st March 2005, 12:24 AM

I've used both on mosfets, and found that every time I've come back to mica with grease. It just seems to run cooler on devices dissipating close to 40W each.

I know the figures on the Bergqvist product look good, but I can't help thinking they don't match mica and grease, correctly installed. And mica is MUCH cheaper......

Cheers,

Hugh

anatech · 31st March 2005, 01:27 AM

40W each. Hot! I have found the same to be true as Hugh's post. Preparation and proper application always mean more at the end.

SO how hot do you figure they will run on your sinks?

-Chris

Mark A. Gulbrandsen · 31st March 2005, 05:36 AM

I just used the Thermalloy ceramic/alimnium oxide pads on my KSA-50 and they work great! I got them surplus locally for 50 cents each. They still do require thermal grease. I believe that these are meant to replace the berrilyum oxide pads of yesteryear. Even the list price of .70 for the TO-247 is not all that bad.
http://www.aavidthermalloy.com/produ...te.shtml#oxide

Mark

LineSource · 31st March 2005, 05:39 AM

Take a look at silver loaded greases like artic silver.

http://www.arcticsilver.com/

I use this with mica insulators, as the large Sanken bipolars I use have special 2-screw insulators.

There are also diamond dust loaded greases and multi-phase waxes that the CPU over-clockers use.

EchoWars · 31st March 2005, 06:06 AM

Thanks for the input.

anatech...heatsinks will definately get toasty. Got thermal controlled fans on 'em.

I have some mica that are super thin, and plenty of Arctic Silver. But I also got these here K10 pads. Perhaps I should save the K10's for an application where heat output isn't quite so extreme...

30th March 2005, 10:16 PM	#1
EchoWars diyAudio Member Join Date: Dec 2002 Location: Left of the Dial	Mica or Bergquist K10 Pads...Can't Decide!! Have a Class A amp that I'm working on...the TO-3 outputs are disappating about 40W each. I've been reading and looking at specs and still can't decide whether to use regular Mica insulators with grease, or Bergquist K10 sil-pads. I love the idea of skipping the damn grease, but are the K10's good enough for the job? Thoughts are really appreciated...

31st March 2005, 12:24 AM	#3
AKSA diyAudio Member Join Date: Sep 2001 Location: Melbourne, Australia	I've used both on mosfets, and found that every time I've come back to mica with grease. It just seems to run cooler on devices dissipating close to 40W each. I know the figures on the Bergqvist product look good, but I can't help thinking they don't match mica and grease, correctly installed. And mica is MUCH cheaper...... Cheers, Hugh __________________ Aspen Amplifiers P/L (Australia) www.aksaonline.com

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30th March 2005, 10:34 PM	#2
sam9 diyAudio Member Join Date: Jun 2002 Location: Left Coast	Per the datasheet the K-10 is about as effective as mica. In actual use I've found they are easier to use than mica and conform to irregularities better. They may be slightly more vulnerable to being pierced by small metal chips, grit, etc. --- so pay attention to cleanliness. I suspect surface flatness and correct torque will have a bigger impact than mica vs k-10. I don't think either will make a significant difference in the amount of heat dissapated relative to the other.

31st March 2005, 01:27 AM	#4
anatech diyAudio Moderator Join Date: Jun 2004 Location: Georgetown, On	40W each. Hot! I have found the same to be true as Hugh's post. Preparation and proper application always mean more at the end. SO how hot do you figure they will run on your sinks? -Chris

31st March 2005, 05:36 AM	#5
Mark A. Gulbrandsen diyAudio Member Join Date: Sep 2001 Location: Salt Lake City	I just used the Thermalloy ceramic/alimnium oxide pads on my KSA-50 and they work great! I got them surplus locally for 50 cents each. They still do require thermal grease. I believe that these are meant to replace the berrilyum oxide pads of yesteryear. Even the list price of .70 for the TO-247 is not all that bad. http://www.aavidthermalloy.com/produ...te.shtml#oxide Mark

31st March 2005, 05:39 AM	#6
LineSource diyAudio Member Join Date: Sep 2003 Location: SiliconValley	Take a look at silver loaded greases like artic silver. http://www.arcticsilver.com/ I use this with mica insulators, as the large Sanken bipolars I use have special 2-screw insulators. There are also diamond dust loaded greases and multi-phase waxes that the CPU over-clockers use.

31st March 2005, 06:06 AM	#7
EchoWars diyAudio Member Join Date: Dec 2002 Location: Left of the Dial	Thanks for the input. anatech...heatsinks will definately get toasty. Got thermal controlled fans on 'em. I have some mica that are super thin, and plenty of Arctic Silver. But I also got these here K10 pads. Perhaps I should save the K10's for an application where heat output isn't quite so extreme...

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