Small heat sinks on pills

[loosecannon]

so glad to see im not the only one telling people to turn their amps upside down lol.

this 'argument' has been going on a long time and i'll bet there is an old thread here where we went deep into the know about it.

my DX400 has been running for many years and i can be extremely long winded.
LC

 

[Blackcat630]

My old TS Killer Bee sits under my truck seat upside-down. To have the heat sink facing up as opposed to into the carpeted floor is a no brainer... I run SSB 95% and don't drive the piss out of it so heat probably wouldn't be an issue anyway. I have gotten good at knowing what does what upside-down when reaching under the seat...

 

[BC Coyote]

My old TS Killer Bee sits under my truck seat upside-down

This took me right back to when I had a firewood business in the mid to late 1980's. We had a base station and three trucks all with radios in them....... mine with a 108 inch whip, a TRC-453 and an old Palomar 200 upside down under the seat. We ran AM channel 10 for business use and I'd shoot skip on sideband while delivering loads of wood.
Like you, I could easily work the upside down switches on the amp, even in that old GMC truck with Armstrong steering, in the dark, bouncing down the mountain on a logging road !!

 

[linearone]

I recall BBi saying that polishing off the oxide on the heat sync makes a big difference.

And like the prices, not all heat sync compound is created equal.

If the amp has no fan, depending on the orientation of the heat sync fins, it might be worth setting it on its side. Convection is what cools the heat sync, so when convection brings the hot air to the bottom of the amp where it has to stop and move sideways under the force of the convection below, it stays warmer.

Having as flat and smooth as surface on the heat sink as possible is absolutely advantageous to a certain point, I find that the people that polish the heat sinks don't take into account that they can polish grooves into the heat sink with whatever their polishing with, it's very easy to do on a piece of aluminum. I've always chose to sand it as flat as possible using a very flat piece of glass or a very very flat piece of metal as a sanding block. I found slightly lower temperatures going from 220 grit and ending at around 800. Anything more than that. You're just showing off. In the real world , on truly critical components ,heat sinks are sent to a surface grinder to make sure they're perfectly flat with a very fine wheel. At least that's what we did in the mainframe industry