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

[EchoWars]

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]

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]

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]

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]

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/products/standard/access/insulate.shtml#oxide

Mark

 

[LineSource]

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]

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...