Millett "Starving Student" hybrid amp
May 17, 2008 at 8:47 PM Post #256 of 7,277
Quote:

Originally Posted by tomb /img/forum/go_quote.gif
On the other hand - if you look at Nate's pics, he used screws. Unfortunately, I think we're stuck with pulling the pins out if you go that route. I didn't see any "no pin" options for the size heat sinks we need at Mouser or DigiKey.


Just a word of warning, I've never successfully pulled a pin from a heatsink. I've tried, not all that hard, but it seemed like it would be a recipe for bad things to happen.

Someone should have a closer look at 707-411626B25 from Mouser, I don't see any pins and I think that this part would be sufficient. Actually, 707-411621B25 might be fine as well.
 
May 17, 2008 at 9:14 PM Post #257 of 7,277
I'll look into that one later today, Nate. Nice catch...I was seconds from clicking CheckOut at Mouser!

I tried to find those heatsinks at the Comair Rotron website, but Mouser seems to have fudged the part numbers. There are some similar ones there, but not the matching ones. Still, the idea of the mfr having tapped holes seems a lot better than me flailing around with a running drill in my hand.

Off to Costco. Sure wish they had a DIY aisle...

"Teach a man to DIY, and he'll sit and wow at his creations. Teach a man to shop at Costco, and he'll eat like a king."
 
May 17, 2008 at 9:15 PM Post #258 of 7,277
Quote:

Originally Posted by n_maher /img/forum/go_quote.gif
Just a word of warning, I've never successfully pulled a pin from a heatsink. I've tried, not all that hard, but it seemed like it would be a recipe for bad things to happen.

Someone should have a closer look at 707-411626B25 from Mouser, I don't see any pins and I think that this part would be sufficient. Actually, 707-411621B25 might be fine as well.



Thanks for those links - guess I wasn't looking at this "Comair Rotron" brand. (I never tried pulling a pin, either.
wink.gif
)
 
May 17, 2008 at 10:26 PM Post #260 of 7,277
Yeah, as far as pulling pins on those heatsinks, it sucks. They do not come easily, at all. If you can find pre-tapped, or even just holes, go for it. Tapping holes is easy enough, and I've never liked the idea of tapping with a drill, I always do it by hand.
 
May 18, 2008 at 2:18 AM Post #261 of 7,277
In my experience standard hardware store washers (I think they're silver-nickel plated) accept solder pretty easily.
Just get a coating solder on the washer first, then put it in place and it should be the same as soldering to a pcb.
 
May 18, 2008 at 5:20 AM Post #264 of 7,277
Quote:

Originally Posted by trains are bad /img/forum/go_quote.gif
I had to use 215kOhm resistors because I didn't have any 220s. I don't suppose this will be a problem, will it?


I don't think it will. At the very least all four (R2, R4, R8, R10) should all be the same, which you've covered. My only question would be the voltage change now going to the tube on pin 1 (and across C2).
 
May 18, 2008 at 5:45 AM Post #265 of 7,277
Quote:

Originally Posted by malldian /img/forum/go_quote.gif
If you guys think this is big enough, I found my case:

Newegg.com - Computer Parts, PC Components, Laptop Computers, Digital Cameras and more!



I don't think that case will work very good in this application. It is just too small. The capacitors will hardly fit in there, let alone having to wire everying and then slide it in from the side. That would be a damn slick case for an AlienDAC or something those.
 
May 18, 2008 at 6:33 AM Post #266 of 7,277
Quote:

Originally Posted by n_maher /img/forum/go_quote.gif
Someone should have a closer look at 707-411626B25 from Mouser, I don't see any pins and I think that this part would be sufficient. Actually, 707-411621B25 might be fine as well.


In the end (and the end is at about 11:30 this evening) I chose the 707-411626B25. The thermal properties looked better than the one that is on the BOM, and if I need to switch out of my proposed wood box to accommodate these, then so be it.

Onward! (Hey, I got some Alien DAC parts while at Mouser, too! W00t!)
 
May 19, 2008 at 1:31 AM Post #268 of 7,277
Quote:

Originally Posted by bhjazz /img/forum/go_quote.gif
I don't think it will. At the very least all four (R2, R4, R8, R10) should all be the same, which you've covered. My only question would be the voltage change now going to the tube on pin 1 (and across C2).


Well 220 * .05 is 11, and 220 - 215 = 5, so given that 5% resistors were spec'd in the original starving student design, I reasoned I would be fine. That was my justification anyway.
 
May 19, 2008 at 2:17 AM Post #269 of 7,277
OK, I just finished ordering the parts for this, except for the:

150uF 63V low-ESR electrolytic capacitor

Which are backordered at Mouser. I'll try my local shop, but any suggestions for alternate parts for C1,C3,C5,C6?

Thanks,

__Roy
 

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