I’m gathering parts at the moment for a Shruthi with the TubeOhm ladder filter. I’d like to build my own case with walnut sides and a laser engraved black perspex front. I notice that the standard perspex cases are full of holes. Are these decorative or do any parts of the Shruthi generate enough heat to require ventilation? Will I be OK with a closed case? I presume that if I choose my power supply carefully, the regulators shouldn’t have to dissipate too much heat.
If you use a 7,5V power supply(a good one, not chinese “7,5v power”), and mayhaps slap a heatsink on each regulator(since you will be enclosing the case all around) should in theory be perfectly fine…
The reason for the holes is people powering their shruthi at 12+ volts, which does generate a decent amount of heat…
The 7805 voltage regulator generates a bit of heat, depending on the voltage of the DC adaptor. The rest does not generate much heat unless you have a short somewhere, which you probably will want to avoid anyway. You’ll need some cooling vents in the area of the 7805 but definitely not as many as the standard plexi case. If you have some in the bottom and some in the rear surrounding the cutout for the DC socket you should be OK.
That’s because people don’t know that the difference between the input and output voltage of a linear regulator is wasted as heat.
I notice the metal case just has a few slots above the DC jack, though I don’t know if there are any slots in the bottom. I suppose if I have a similar amount of ventilation to that there should be no problems. I haven’t chosen my power supply yet but I’ll make sure I check the loaded output with a multimeter before I settle on one.
Heat will also radiate from the metal of the enclosure. If the air inside gets hot, it will heat up the metal which will be cooled by the environment around it. If you have a solid wood case or something similarily bad heat-conducting, this won’t work and you might want to have bigger holes than the ones on the metal enclosure.
I personally wouldn’t care too much about heat issues. The Shruthi doesn’t burn enormous amounts of energy if you use a 9V DC power adapter. Build it and run it for some hours. Then check if it gets too warm inside. If so, drill some holes.
Believe it or not - there is a non decorative reason why we cut all these holes into the sides.
Cheers guys, my plan at the moment is to get the boards working before I finalise case details, run it for a little while with a 7.5 or 9v power supply and if anything is getting warm I can incorporate some vents, perhaps along the side where the regulators and caps are and a slot or two in that end of the top.
Using the standard case would be the path of least resistance, but I just find wooden objects appealing! Also, I’ve recently joined a local hackspace with access to a laser cutter, so front panels should be no problem.
For your vent holes, you should place them in a way, that allows cold air to enter the case at the bottom and hot air to leave on the top. Just keep in mind, that hot air moves upwards naturally and use the priciple for ventilation.
A slot above the regulators sounds good.