Heatsinking the Lovoltech JFET

[moe29]

OK guys, i'd like to see some pictures of how you're doing this!


seeing as i'm going to be wiring my Zen 8 circuit point to point, i really
need the JFET to be secure.

 

[Zen Mod]

I still have not any of little jewels,but this is what I do before with similar cases

 

[mpmarino]

digikey doesn't seem to stock those 'whatevers'. any idea where to get one?

 

[Zen Mod]

digikey doesn't seem to stock those 'whatevers'. any idea where to get one?

what?
grey didn't send same number of whatevers as Jfets- in same envelope?

 

[GRollins]

Oh, man...so that's why I've got so many 'whatevers' sitting here! I forgot to send the silly things out with the JFETs.
Now, that's a big OOPS...

Grey

 

[jh6you]

Gee . . .
As I do not know what is whatever,
I use the juice maker . . .
But, stop the pressing just before you see the black juice . . .

jh

 

[moe29]

I'm seriously thinking about using this:

Arctic Silver Thermal Adhesive

Even if you decided to use the heatsink for a different amp, the part
is so small - you could easily work around it.

...just an idea

 

[mpmarino]

Choky's solution is real good IMHO. The most common way I have seen a single device mounted in an industrial/heavy commercial app is as follows. The gray bar being a bent piece of heavy guage steel.

 

[GRollins]

In principle, you can solder the tab to a piece of copper. This is fine for assembly, but a nightmare for troubleshooting/service. You can also overheat the device and cause premature failure.
I prefer a mechanical system.

Grey

 

[Zen Mod]

Choky's solution is real good IMHO. The most common way I have seen a single device mounted in an industrial/heavy commercial app is as follows. The gray bar being a bent piece of heavy guage steel.

off course I am in right....

same as with clamping speaker baskets in some pro applications.........

 

[kiasu]

See this heatsink.

 

[john-china]

See this heatsink.

where? what?

As I do not know what is whatever

i can use any other DPAK transistors which is useless or obsolete as "whatever".

 

[kiasu]

Sorry about this. I have been sleeping and this is my first post.
How to post link?

http://www.altronics.com.au/index.asp?area=item&id=H0639

 

[GRollins]

The general idea will work, but a heatsink that small is going to get awfully hot with two or three watts going through it. Your other option, of course, is to limit the heat the JFET produces to something that the heatsink can handle.

Grey

 

[Stones]

Sorry about this. I have been sleeping and this is my first post.
How to post link?

http://www.altronics.com.au/index.asp?area=item&id=H0639

The general idea will work, but a heatsink that small is going to get awfully hot with two or three watts going through it. Your other option, of course, is to limit the heat the JFET produces to something that the heatsink can handle.

Grey

Drill a hole in the top of that and you have instant screw on clamp.

 

[kiasu]

Mount the JFet directly on the heatsink. This heatsink is then mounted onto the big heatsink with insulation in between.

 

[steenoe]

Here is how I did it:
http://www.diyaudio.com/forums/showthread.php?postid=850802#post850802
I very much prefer a bolt on each side of the devices, as it makes for a far more even pressure on the device.

Steen

 

[thorstenlarsen]

I'm seriously thinking about using this:

Arctic Silver Thermal Adhesive
...just an idea

A friend of mine tried it in a classA amp. He managed to reduce the case temperature of the transistors around 3 degrees C. That would be around a 10 % reduction of the temperature-rise .
3 / ( 50 case - 20 ambient )
How does it sound Steen ?
thorstenlarsen

 

[steenoe]

How does it sound Steen ?

I only managed to bring up and adjust one channel so far, so I didnt really listen to it yet. I am having trouble with the other channel. I hope to get it made today.

Steen

 

[chipco3434]

I used an aluminum bar to clamp irf240's on my A30. Worked great... for about 8 hours of playing time. The 6-32 screws clamping the FET loosened under thermal cycling. Results were catastophic.

I think this product is a solution in that it has more "spring action".

http://www.aavidthermalloy.com/cgi-bin/mxclipsrch.pl?Package=ALL&Attach=SCREW&search1=search

My 2 cents, but this is better science than my DIY solution.