Hello,
I'm looking for simple class A projects to try out building an amp. My estimates are that I need an absolute max of 2W to a 4ohm load, the drivers will cover 125hz to 20khz, no need for low bass. I have this v large heatsink that I purchased for a high-powered LED project but didnt end up using. If I find an amp that I can manage to build successfully I plan to expand it to 24ch to go with my line array project. Thanks!
-Eric
I'm looking for simple class A projects to try out building an amp. My estimates are that I need an absolute max of 2W to a 4ohm load, the drivers will cover 125hz to 20khz, no need for low bass. I have this v large heatsink that I purchased for a high-powered LED project but didnt end up using. If I find an amp that I can manage to build successfully I plan to expand it to 24ch to go with my line array project. Thanks!
-Eric
It would be suitable for a very tall amp. 🙂 You do want the air to flow along the fins, so the fins need to be vertical. You could run it through a table saw (with a non-ferrous metal cutting blade) a couple of times to create 2-4 chunks for use in smaller amps. A flea power Class A amp wouldn't require much heat sinking.
Tom
Tom
Look at lineup projects, there was one recently where boards were available from some nice member. I remember it sounding great especially highs. I will try to find it, it was based on c5200 outputs.
https://www.diyaudio.com/community/...o-feedback-simple-circuit-great-sound.234515/
https://www.diyaudio.com/community/...o-feedback-simple-circuit-great-sound.234515/
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ACA Mini! Low power, easy to build, fantastic class A sound. 12 of them would be hilarious. 😀 Beast-With-A-Dozen-Amps.
That sink may even work, but like Tom said, it would be very tall, or you could cut it.
adason's advice is good.
That sink may even work, but like Tom said, it would be very tall, or you could cut it.
adason's advice is good.
I bet getting it cut would cost me more than original price (iirc ~$20 from a scrap place). I can’t begin to imagine what it was used for if it needed to be vertical.
I had planned to put 1000w of led cob on it to illuminate my back yard for sledding after sunset in the winter. Ended up making smaller 5w lanterns. 🙄
I was hoping to assemble 24ch worth of “flea power” which could all work with this large sink.
You don't know anybody with a table saw or mitre saw? A decent non-ferrous metal cutting blade is not that expensive. Freud/Diablo is available at your local home improvement warehouse (at least in North America). But, yeah... If you fished the heat sink out of a scrap heap, the blade will cost more than the heat sink. Hey... Hacksaw blades are cheap... 😉
Tom
Tom
It probably could. Just make sure you account for the thermal gradient along the heat sink in your thermal math.
This could be helpful: https://heatscapecal.com
Tom
Interesting, I hadn't thought cutting this much metal was possible without bigger shop tools. Very good to know its worth trying. Blade is only $35 at HD, worth it to make this useful. Will need to watch plenty of youtube vids first.
lol first result:
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12" hacksaw blades are like $1 here, for 18tpi bimetallic, carbon steel with HSS teeth.
Normal hand hacksaw, about 1/2" blade width.
$35 is wildly expensive.
Ask for tips at high school shop class.
Normal hand hacksaw, about 1/2" blade width.
$35 is wildly expensive.
Ask for tips at high school shop class.
https://www.amazon.in/MIRANDA-HSS-HAND-HACKSAW-BLADES/dp/B00XLLU71W
Just an example, no ties to seller.
Just an example, no ties to seller.
7" circ saw blade is $35. Getting off topic here though.
I'll look through the links for the ACA Mini and Lineup projects. Thanks so much for those leads.
If you can, use a chop saw, that works, though I have no idea of what is available to you.
For soft metal, it tends to fill up the teeth, look that up as well.
Buying a circular saw blade just for this may be an investment for later as well.
For soft metal, it tends to fill up the teeth, look that up as well.
Buying a circular saw blade just for this may be an investment for later as well.
Just make sure you get a TCG blade specifically for non-ferrous metals. I highly recommend using some A-9 aluminum cutting fluid (not to be confused with A-1 steak sauce).
I have a 10" 120-tooth (or maybe 96-tooth, I forget) Freud TCG profile blade for my mitre saw. I've used it to cut a piece of 1x2 inch aluminum bar stock (along with 1/4", 3/8" bar stock, U-channel, L extrusions, thin aluminum picture frame moulding, etc.) It works beautifully. Just listen to the saw and don't force it. Let the blade do the cutting. But that goes regardless of material.
Tom
Yeah the fins are where I'm curious how the saw is going to handle them. Will have to experiment on some smaller scrap stuff I have and see what happens.
I have seen a picture, taken in Africa? of a whole village and a 36-inch tall I-beam, and a plain hand hack-saw. They cut it through, though probably not in one day.
Then there's me (younger!) and a hand-drill, making a 2" hole through an 11-inch thick old-growth Black locust (extremely hard!) sill to bring gas into my 1830s house.
But 24 2-Watt amps? I'd be real inclined to get a box of $1 stamped heatsinks. Depending what you mean by class A. Push-pull is 2W per device, this will do. 2W SE choke-coupled is 4W/device and may need a $3 extrusion. 1W resistor-coupled is 13W per channel; 4W in device but the surrounding 9W of resistors works against cooling.
This looks like a great little amp. I only see one person asking about using it w/4ohm load:
https://www.diyaudio.com/community/...imple-circuit-great-sound.234515/post-6973557
seems like they are suggesting some configuration changes to work with 4ohms and yield 4w output, but with 30w load. Does that seem excessive or is that typical class A numbers?
Would there be optimizations that could be made to reduce the output/load?
or should I just try building one and go from there? 🙂
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@ericwestpheling,
I have cut CPU aluminum heatsink. It required lot of hard work. clamping the half part to sturdy table helps. While cutting I bent few fins which were straightened out with nose plier. After cutting major chunk cutting fins with small teeth blade helps. Drilling holes also required some effort. but manageable. Some general pictures HERE.
regds
I have cut CPU aluminum heatsink. It required lot of hard work. clamping the half part to sturdy table helps. While cutting I bent few fins which were straightened out with nose plier. After cutting major chunk cutting fins with small teeth blade helps. Drilling holes also required some effort. but manageable. Some general pictures HERE.
regds
Where there's a will there's a way, right?
i'm not dead-set on using this chunk of aluminum if it doesn't make sense, just happened to unearth it today while cleaning my "workshop." Got to thinking "why not class-A? you don't need that much power, should be simple- just bolt a bunch of them to this giant heatsink." but obviously I have a lot to learn.
The "Push/pull, se choke-coupled, resistor coupled" are all various class-A topologies? any reason to look at a specific type for low power use? I am looking for <=2W to a 4ohm load.
I was going to suggest Lineup 4watt Class-A too. I already bought couple of TTC5200 pair especially for that amp 🙂
