Burning temp. of Mj11015 and MJ11016

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ACD has good advice..

Is it the transistor case that is getting hot, or the heatsink?

Absolute temp will also depend on the circuit, and the way the chips handle secondary breakdown under power..

Cooler is always better, double lifetime every 10 C drop.

Cheers, John
 
Hmmm...

The transistor case is getting hot , the heatsink is pretty hot too ..
I could put my hand on it .. i stick it and i didn't burn my finger ... i only got shocked by the 40 V that the amplfier power supply give ..

If i gonna add some fan's , how should i put them ?

I want to put ( one on each board ) them inside the case ( with hold outside ) to suck air from the case and throw it out ( i will place them over the output transistors )

And two on each heatsink to suck air from it .

How should i put them ? To suck air from the case ? Or the suck air from outside and throw it in the case ?

Thanks , Mihai .
 

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Disabled Account
Joined 2003
Directly above them, I would blow the air onto the devices..I think that will be a more focussed cooling stream..but, that will still be an ineffective use of the fans..

I would prefer the fans either over the fins, or under, blowing across them. that is better.

Cheers, John.

PS..gotta bolt..happy holidays, good luck.
 
AX tech editor
Joined 2002
Paid Member
Re: Hmmm...

darkm4n said:
The transistor case is getting hot , the heatsink is pretty hot too ..
I could put my hand on it .. i stick it and i didn't burn my finger ... i only got shocked by the 40 V that the amplfier power supply give ..

If i gonna add some fan's , how should i put them ?

I want to put ( one on each board ) them inside the case ( with hold outside ) to suck air from the case and throw it out ( i will place them over the output transistors )

And two on each heatsink to suck air from it .

How should i put them ? To suck air from the case ? Or the suck air from outside and throw it in the case ?

Thanks , Mihai .

How did you measure the temp? If you can put your fingers on them withour burning (you really can KEEP them on it), they propably aren't a whole lot above 40 celcius.

Jan Didden
 
Ok .

The kit have 400 W x 2 at 4 Ohm , it's a bridged amp ( with a TDA circuit , it can be seen on the board's , it's that long cip , black )

It sound very good .. the only problem is the temp.
At low volume it's about 40 C , at high volume i don't know .. but i think it's about 80 C ...
That's why i want some coolers ..
I still don't know how to put them ... maybe 2 on each board .. mounted on the headsink , not across the fins , on the fins . If i put 2 on each heatsink it should cover it ...

Thank's
 
Hmm..

I use 42 V rail's , i don't have a schematic of the kit's .. sorry ..

Whan i first saw those kit's i couldn't belive their power at a low voltage .. ( 42 V )
But .. i realised that it's true .. because it's a bridged amp .. i ask a friend to mesure with an osciloscope the max power and result about 408 W at 4 Ohm .

Thank's .
 
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