which heatsink is more efficient?

[endia]

hi,
while i was searching adequate heatsinks for symasym i found these two types. i want to use them on two sides of the chassis.. which one is more efficient? which one do you prefer? thanks..

 

[Mooly]

Vertical fins are the best for heat dissipation because the hot air rises freely between the fins.

Strange to say that horizontal fins are used on the Sugden A21a Class A amp and that amp runs really hot. Obviously they (and the case) dissipate the energy sufficiently but it would run cooler with vertical. Maybe a rare case of form over function from Sugden.

I think the horizontal look better though 🙂

 

[endia]

Hi Mooly, thanks..
just looked forum's gallery pages and this explains why most builders choose vertical ones.. besides horizontal look better me too 🙂

 

[Wavebourn]

Heatsinks with pins instead of flat fins are the most effective.

If you orient fins horizontally they are useless for free convention. However you may see horizontally oriented fins when forced air is used, also forced air allows to use densier heatsinks. For free convection optimal distance between fins (width of gaps) is 8 milimeters.

 

[endia]

thank you Wavebourn,
i will use heatsinks outside of the chassis with free air, so i'm sticking to vertical placement with no doubt..

 

[forr]

The lower figure with its vertical fins looks like the front of the Quad 405.
To me, it's the best place to fit heatsinks but few manufacturers do it his way (Quad, DB systems, some old H&K and JVC, I think ).
Note that horizontal are not only less efficient, they will accumulate more dust.

 

[endia]

they will accumulate more dust.

thanks forr.. indeed, that also makes sense..

 

[tinitus]

good to have 'adequate' heatsinks
but to achieve best cooling its equally important to ensure optimal heatspread by mounting the transistors in the right place
sometimes completely neglected
but then optimal cooling may not be necessary