Burning Amplifier BA-2

[tms0425]

Originally Posted by AR2

Yes, that is quite fine, but where to get now those heatsinks?

Yes, we need some people with more of those heatsinks than they need and too many projects

Fortunately I happen to have a little drawer with a few 109's for special occasions and enough 74's if I want to work a little at it.

[cviller]

Originally Posted by tms0425

Yes, we need some people with more of those heatsinks than they need and too many projects

Fortunately I happen to have a little drawer with a few 109's for special occasions and enough 74's if I want to work a little at it.

Those heat-sinks are custom made by EUVL:
http://www.diyaudio.com/forums/showt...38#post1690438

I don't know if he has setup a shop where you can buy them, but mounting the jfet flat to flat with thermal grease and plastic strips around is a perfectly reasonable alternative solution IMHO.

[Zen Mod]

....

but - if you look at Papa's UGS pics ....... jfets are all around ......

[cviller]

Originally Posted by Zen Mod

....

but - if you look at Papa's UGS pics ....... jfets are all around ......

Yeah that is true, but I would bet papas soldering skills are above average here on this forum.

But if people prefer not to have the shortcut on the boards - I can remove it.

[Botte]

cviller,

How are you coming along on the Bias boards?

Thanks,

[AR2]

Originally Posted by cviller

Those heat-sinks are custom made by EUVL:
http://www.diyaudio.com/forums/showt...38#post1690438

I don't know if he has setup a shop where you can buy them, but mounting the jfet flat to flat with thermal grease and plastic strips around is a perfectly reasonable alternative solution IMHO.

Yes, that is how I was doing it so far, but my impression was that Euvil's solution provides some heat sinking. If that is not needed than having them flat to each other is of course quite fine.

[tryonziess]

AR2,
This is a diy forum. Get some thin copper and cutout a suitable shaped heatsink and sandwich it between the two jfets on the flat side. You will have close tracking and cooling at the same time. If you come up with something you are proud of let us see it. There are no constraints placed on diy.
Tad

[AR2]

Originally Posted by tryonziess

AR2,
This is a diy forum. Get some thin copper and cutout a suitable shaped heatsink and sandwich it between the two jfets on the flat side. You will have close tracking and cooling at the same time. If you come up with something you are proud of let us see it. There are no constraints placed on diy.
Tad

I think you guys are missing my point.
If we decide to design the circuit and jFet position to the Euvil's heatsink, which has two jFets distributed in line than it is hard to do what is normally done in situations like this - attach jFets flat face to face. I would be my preference to have them face to face. I love what Euvil did with his heat sink, but if the sinking is not required, than it would not make any sense to design board right now based on it, because it is not possible for anyone just to go and buy those heatsinks. If we decide to to Euvil's rout, than my question was how or where to get those, since that is one very elegant solution. I hope this makes it clear for you.

[AndrewT]

Euvls' heatsink solution was to allow thermal matching to fit the standard 7pin 389/109 pin layout.

These are obsolete devices and there is no point in designing for an obsolete pin configuration.

[udailey]

Maybe he meant this instead.. Not sure how you would attach them to the plate but I suppose super glue on the sides of the TO-92 would do it.
Uriah