[Juergen]

My OPA633 buffers in my PPA are running very hot

(they will give you a blister if you touch them for more than a second or two). This topic has been covered elsewhere on this forum so I am not asking for a solution. What I am interested in is how this might affect the buffers themselves. I know that excessive heat will shorten their life. Has anyone here lost a buffer this way? Will they just stop functioning one day? Will they die a slow death? I am concerned that perhaps they are not currently operating at their full sonic potential. It may not matter since I plan on installing Glassman’s Diamond Buffers when they are available.

 

[Megaptera]

If you're concerned about them at all, I'd pick up some heatsinks. Some chips are more sensitive to heat than others, and it's definitely possible that it's affecting their performance (though I haven't used that particular chip myself).

 

[Juergen]

I found some real inexpensive heatsinks

They are actually in use. Not exactly practical since gravity is all that holds them on

 

[beamrider]

Chuck E Cheese tokens have the absolute WORST thermal conductivity rating of all coins, man. I can't see how they are making a difference.

 

[Megaptera]

If you're really desperate, apparently toothpaste and vegemite are better at sinking heat than most thermal pastes. (Yeah, I know that's not the job of the paste, and neither one would last.... but that's not the point

)

 

[einolu]

yeah, T-tokens on the other hand can be used to cool P4's running at 5.8 ghz without air cooling!

jk, there are some small heatsinks for sall at radioshacks that should do the trick (although im not sure if they are supposed to get this hot since I never build your amp). They are pretty cheap, and look cute, good luck!

 

[tangent]

The 633 doesn't have thermal protection, so what will happen is that the lifetime of the part will decrease as the heat goes up. If it goes high enough, you can damage the part very quickly.

There are secondary effects, too. Hot buffers raise the ambient temp inside the case and thus make other parts in there hotter, so their lifetime reduces, too. The ones you're most worried about in this case are the electrolytic capacitors. Every 10C rise halves their lifetime.

The same rule of thumb applies to other parts, but since most parts besides electrolytics have such high lifetime ratings at moderate temperatures, it isn't a big deal. Infinity divided by 2 is still infinity.

The datasheet has a section, Overload Conditions, that goes into this in more detail.

 

[rayofsi]

i have plenty of heatsinks http://www.ufokillerz.com/heatsinks.jpg

the big ones can cover 4, and the small ones can cover 1
if you need some give me a pm, i can provide some at a decent cost.

 

[Juergen]

Quote:

Originally Posted by ufokillerz if you need some give me a pm, i can provide some at a decent cost.

Thanks, I will probably go to Radio Shack as einolu mentioned. They have one that's a bit too large but since I only have one buffer per channel populated, fitting it in won't be a problem. Fastening it down is another story.

 

[null]

Quote:

Originally Posted by Juergen Thanks, I will probably go to Radio Shack as einolu mentioned. They have one that's a bit too large but since I only have one buffer per channel populated, fitting it in won't be a problem. Fastening it down is another story.

http://www.arcticsilver.com/ good luck!

 

[Megaptera]

I don't know that I'd bother with any fancy thermal grease -- the Radio Shack stuff should do just fine for temporary buffers (especially since the sink itself is going to be larger than necessary) and it'll be a lot cheaper.

 

[flecom]

arctic silver also has an epoxy, which would solve his issue about how to keep the heatsink in place

 

[rayofsi]

my sinks all have thermal tape on it. Very sturdy thermal tape.