Where do I get big heatsinks? :S

[Plecto]

Hi. I have been thinking about this questions and I haven't really found an answer to it I am currently working on a LM1875 chip amp and was planning to just mount the chips directly to a metal enclosure, but then I got the idea of making an enclosure out of plexiglass, but that means I'm back to finding a decent heatsink. I have bought a couple of 5C/W heatsinks like these:



I've used them for testing purposes, but they are hard to place on a finished board as they demand some space on the pcb. They aren't big enough for the LM1875 either I believe. What I wan't is heatsinks like these:



I believe these are a lot easier to mount as I can just put all the TO-220 packages at the end of the board. The ones I find on ebay cost like 15-20USD which is enough to rather consider a metal enclosure or use a fan (which I don't want). Are there cheaper places to get heatsinks? Or perhaps some other metal component that can be used as a heatsink? Perhaps they can be made? They are just a lump of metal after all :P

[turk 182]

when it comes to heatsinks try a trip to your local music store or repair shop to see if they've got anything in the way of amps that are heading for the turf pile.it will mean doing a little work to extract the heat sink but the bonus can be all sorts of other parts to play with!
i often check flea markets and thrift shops as well as second hand stores

[Plecto]

Yeah I've thought of scavenging some electro dump, perhaps I'll find some transformers aswell The thing I forgot to mention is that I am hoping to get this amp "pro" enough to sell it and I would really like an indenfinitive source of these heatsinks. Another thing worth mentioning is that I live in Norway and the prices here are pretty high so buying second hand equipment just for the heatsink is not an option. Are there any sites that might be cheaper than the heatsinks I've found on ebay?

[Plecto]

Actually, after some more searching on ebay I found several heatsink with a more acceptable price. This one should do for 2xLM1875, no?

1 Piece Aluminum Heatsink for Amplifier 50MM×110MM×45MM | eBay

11USD and free shipping isn't bad. The heatsink is 50mm×110mm×45mm

[tinitus]

these kind of smaller heatsinks you may be able to find in older electronics scrap
sometimes mounted outside on the back, but often inside the box

but a good chunk of alu list might do the trick

[turk 182]

sorry didn't realize you are doing it as a commercial venture
turk182

p.s.: there's alot of amps using lm1875 so what unique about yours?

[Plecto]

p.s.: there's alot of amps using lm1875 so what unique about yours?

Nothing, but it's hard to come by homemade amplifiers in Norway. I might be able to sell this thing for half the price of what an equally powerfull professional amp would cost. This is more for fun though, would be cool to see if anyone would wan't it.