I respect Nelson, but I don't automatically ape everything he does. I'm using aluminum oxide insulators with grease on a lot of my designs, esp where there's high voltage or a moving drain (or in the case of a lateral, a moving source) involved. And again, a thermal interface product that resists caking would have advantages. I still use sil-pads in less critical positions.
Pa is using gum thingies where dissipation per device isn't high .....usually PL amps are having plethora 
of mosfets , each of them being cold as belly of typical HD rider
FW amps , on the other side , even if sissy by total heat , comparing to most PL ones, are having few outputs , bloody hot , as my two cells colliding
go figure
of mosfets , each of them being cold as belly of typical HD riderFW amps , on the other side , even if sissy by total heat , comparing to most PL ones, are having few outputs , bloody hot , as my two cells colliding
go figure
wrenchone: I think you have valid concerns. Because of those I switched to using Quantum from TIM-Consultants a few years back. It beat out the high priced diamond dust and silver particle products for thermal conductivity, yet remains very stable with no pumping, which is what makes it so good. This product is different and I will keep using it on all my builds. It is reasonably priced, also. Google their site to order direct. I also read the whole testing done on their older product by BenchmarkReviews.com. BTW, I am looking forward to hearing about your latest builds.
having nuttin' with price range .....
in fact , preparing and mounting with mica and goop is more time consuming than "just slamming" gum thingie under the mosfet
so , with that logic , it should be backwards - eenyweeny and sissy FW amps should gave gum thingie , and PL beasties should have mica and goop
so - it's simple logic - what's better for purpose ;
and it's also illustration of proper engineering approach - use what's best bang for the buck in manufacturing process
It seems fairly useless to rely on these manufacturing anecdotes to determine what's "best". It may well have everything to do with nonperformance factors (who's building those amps? Overarching reliability?) than thermals.
There are a number of working solutions, but it's hard to argue with Wrenchone's pursuit of non silicone TIM if they afford less migration, especially under high nominal conditions (and the attendant low thermal resistance Al2O3 insulators to keep the transistors happy).
Choose a solution that works for you and execute it well.
There are a number of working solutions, but it's hard to argue with Wrenchone's pursuit of non silicone TIM if they afford less migration, especially under high nominal conditions (and the attendant low thermal resistance Al2O3 insulators to keep the transistors happy).
Choose a solution that works for you and execute it well.
I was referring to PL using multiple output devices which are biased lower and run cooler. NP also mentioned that the FW heatsinks were bead blasted and had to change over to mica and goop. If that was PL they probably would reject the part. Putting mica and goop on four outputs doesn't take a lot of time. But putting it on 16 pairs would.
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