Thanks, but I'm in Buenos Aires, some 8000 miles away
Problem is, up to a short time ago dollar/toy shops were full of nice tin cases in all sizes and shapes (printed with Barbie/Hello Kitty/etc. graphics for young girls), now I can't find them anywhere, shop owners inform me "they are out of fashion" and try to sell me the current (plastic) ones.
So far I have secured 3 tin cans which approximately fit the specs:
1) a round tin ashtray, 3 3/4" diameter by 1 1/2" high. Of course it has a round cover
2) a rectangular tin (Winnie the Pooh graphics) pencil case, 8" x 2 1/4" x 3/4" (if no better found, I'll use this one)
3) a sardine can, emptied by yours truly, 2 1/2" x 4 1/4" x 1" which also looks promising.
It does not have a cover, of course, which was cut away with a tin can opener
, but I can fashion one out of some aluminum sheet.Which is good because it's a better heatsink than paper thin tin.
Well, if by the end of the week I don't get a better one, I'll use one of these.
Stay tuned
These are car air fresheners:
Maybe they're at the auto parts store or that sort of department in a larger store?
An externally hosted image should be here but it was not working when we last tested it.
Maybe they're at the auto parts store or that sort of department in a larger store?
I'll check.
So far my favorite is the pencil box, just checked my standard 2200uFx50V radials fit very well , I think 4700x25 are about same size, so I might either make a monoblock LM3886 40/50W amp or stereo 2 x TDA2050 .
I might even fit a flat CPU fan inside , for forced cooling.
This is slowly taking form in my mind.
Just don't want to rush until I have the physical space defined.
The actual electronics part is a piece of cake.
PS:you hit the nail right in the head, with the "Hello Kitty" can
So far my favorite is the pencil box, just checked my standard 2200uFx50V radials fit very well , I think 4700x25 are about same size, so I might either make a monoblock LM3886 40/50W amp or stereo 2 x TDA2050 .
I might even fit a flat CPU fan inside , for forced cooling.
This is slowly taking form in my mind.
Just don't want to rush until I have the physical space defined.
The actual electronics part is a piece of cake.
PS:you hit the nail right in the head, with the "Hello Kitty" can
Probably much more than the project is worth
Don't worry, I haven't been yet to Downtown.
Where I'll probably buy an actual Altoids (o Cadbury/Riggs or any other) can, and empty its contents .... although my Doctor will frown on that.
Don't worry, we're almost there.
This is for Fun, anyway
Don't worry, I haven't been yet to Downtown.
Where I'll probably buy an actual Altoids (o Cadbury/Riggs or any other) can, and empty its contents .... although my Doctor will frown on that.
Don't worry, we're almost there.
This is for Fun, anyway
Hey !! , why *empty*???
You sound like my Doc/wife/daughter
Anyway, don't worry, I've settled on the Winnie the Pooh pencil box, being rectangular but most important, flat bottomed, allows me to pop rivet an aluminum rectangle as heat sink, thermally coupled with some grease.
Now, where did I put those TDA2050?
I'll build it this weekend.
You sound like my Doc/wife/daughter
Anyway, don't worry, I've settled on the Winnie the Pooh pencil box, being rectangular but most important, flat bottomed, allows me to pop rivet an aluminum rectangle as heat sink, thermally coupled with some grease.
Now, where did I put those TDA2050?
I'll build it this weekend.
I've got some ideas for you.
With a discrete amp possibly in the lead at the moment, you might want to get a bit competitive with a "made for compact stereo" chip amp. That compact stereo class of chip amplifiers feature generally cooler running and audibly level harmonic response that makes component selection and fidelity much easier to do.
The monobloc option is either a parallel amp or has parallel output devices (same number of output devices and same minimum total system power as the stereo build).
Instead of a fan demonstrating that inefficiency has required forced air cooling, you might consider a cool running amplifier, feet on the bottom of the enclosure, passive intake vents through the bottom of the enclosure (vents underneath caps and also vents at heatsink/spreader materials), and passive output vents at near the top of the enclosure. It is also possible to use metal feet with a bit of rubber on the bottom.
Good power and other filtering and compensations all to restrict the amplifier to "only audio work" can make it run quite cool by increasing the efficiency of its primary task, which is only audio. Datasheets list some "optional" rf filtering and you can check to see what will make your amp run cooler. This is a linear amplifier efficiency contest.
Would be so very surprising for Hello Kitty mint tin amp to output exuberant hi-fi. Really fun to show it to friends and neighbors just to see their expressions.You hit the nail right in the head, with the "Hello Kitty" can
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the 1.76 oz (50g) Altoids tin has a surface area of over 17 inches! Sides included. Output devices should thus be placed on the bath-tub portion of the tin.
I placed a 6 ohm 50W dale resistor in the tin, thermal goo and attached via 4-40 screws. cooked it for 10 minutes @1.4A:
An externally hosted image should be here but it was not working when we last tested it.
Temperature rise after 10 minutes was all over the place -- from almost 65 degrees at the lip end of the cover to 40 degrees (C) where the cover is attached to the bath-tub. Thus you could fry an egg on this thing.
Wow !!
THANKS a lot for making this IMPORTANT experiment !!!
I didn't build mine yet, those pesky customers who demand what they've pre-paid for keep me busy!!!
But it sort of confirms my idea of adding a small CPU type fan .
That *besides* my original idea of pop riveting an aluminum rectangle to the case bottom, with thermal paste in between, of course.
Thin tin by itself is a very poor thermal spreader.
Just curious: what was the temperature just over the resistor?
Because what you mentioned ("lips" , "cover", is some distance away).
THANKS a lot for making this IMPORTANT experiment !!!
I didn't build mine yet, those pesky customers who demand what they've pre-paid for keep me busy!!!
But it sort of confirms my idea of adding a small CPU type fan .
That *besides* my original idea of pop riveting an aluminum rectangle to the case bottom, with thermal paste in between, of course.
Thin tin by itself is a very poor thermal spreader.
Just curious: what was the temperature just over the resistor?
Because what you mentioned ("lips" , "cover", is some distance away).
So thermal resistance is somewhere around 3.2C/W. Very useful to know, thanks! Do you know the ambient temperature at the time of the test?
So it would take ~47W to fry a silicon output device at 150C. Although the lytics would be long gone by this time.
Lets identify the max internal temperature tolerable for preserving the lifespan of the components. Then we'll know how much we can dissipate in this tin with reasonable longevity.
So it would take ~47W to fry a silicon output device at 150C. Although the lytics would be long gone by this time.
Lets identify the max internal temperature tolerable for preserving the lifespan of the components. Then we'll know how much we can dissipate in this tin with reasonable longevity.
Thermal rise was 65 degrees -- it's a little warm in the workshop in the winter as the furnace is nearby -- so it started at 25 and ran up to 90. I think it can be improved by using a bit of 1/8" aluminum stock.
I will use lateral mosfets, lower over-head means less heating, no necessity of source resistors.
I will use lateral mosfets, lower over-head means less heating, no necessity of source resistors.
Lower cost versions of lateral mosfet include Power Mosfet and under-volted TDA7296.
Plenty of room:
The substrate is 3/16 aluminum and fits into an altoids tin.
An externally hosted image should be here but it was not working when we last tested it.
The substrate is 3/16 aluminum and fits into an altoids tin.
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