P68 Heatsinks

[kinser]

Hey all,
I'm planning t build rod elliotts P68, not the 500w and not the 300w but both, meaning the simple 300w version but also to be able to run it at 70Vdc +/- with an 8 ohm load ONLY! so i pulled out 2 heatsinks from my sansui R-550 reciever. I wanna make a tunnle with 2 fans at each end (one sucking air in and the other blowing air out) and having the heat sinks on each side of the tunnle. BUT..... there are howls on the heatsinks form the transistors that where mounted on it.. so i would like to know if i can put a piece of aluminum on the heatsinks(the sind that the transisters are mounted on) and mout the transistor on the aluminum.
can I do this? (I added 2 pics of the heatsinks)

Thanks
Kinser

 

[kinser]

another pic

 

[pinkmouse]

Even with fans, they are no way big enough for 300W.

 

[richie00boy]

Assuming that's a 1.5V AA battery I back you up pinkmouse. They need to be double that size for that kind of power.

 

[edl]

huh...
that heatsink is enough for a 20W amp...
with fan 30-40W max....

+/-70V rails and 8ohm means 200W-RMS

you will need a MUCH bigger heatsink

 

[kinser]

edl,
20 watts hu? no! a gainclone uses a smaller heatsink then the ones i have. this amp has a 260va xformer with 25-0-25 output (35vdc+/-) which will be about 100 watts max(per channel)!

The heatsinks had 2 output transistors and a driver transistor on each one. but i came up with an idea! i have a diffrent heatsink which will be good for 2 transistor. so i tought put Q9-Q12 on the the 2 silver heatsinks (the pics i posted, 2 transistors per heatsink) and put Q7 and Q8 on the other heatsink(the one i described as sec ago)

And still use the fans!


Thanks kinser