Exactly, no pwm chopper for the power or dimming. Most of the info for powering leds on the interweb is the old-skool type with resistors, and that is what you want to use for that application.
Yes, that is correct, and something else to consider is that the heat dissapated from leds can be something to manage. The best way imo is to just derate them so they are running at a fraction of their rated output current. While this is going to be not as bright, it is still easier to have more leds than to buss the heat somehow.
Also make sure and note the polarity of the leds, they only work the right way, and usually don't work after power has been applied the wrong way.
Also make sure and note the polarity of the leds, they only work the right way, and usually don't work after power has been applied the wrong way.
I recommend you use an adjustable current source like this:
This will supply anywhere from 1 mA to 12 mA to allow dimming the LED to an acceptable level.
You can string together multiple LEDs in series as long as you supply enough V+ voltage to overcome the total voltage drop of the whole string.
Mike
This will supply anywhere from 1 mA to 12 mA to allow dimming the LED to an acceptable level.
You can string together multiple LEDs in series as long as you supply enough V+ voltage to overcome the total voltage drop of the whole string.
Mike
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What source of power is your DAC going to have?
How much heat is produced will depend on a few variables such as the type of LEDs you use, how many, the airflow arrangements of the enclosure etc. I wouldn't be tooworried out heat generation, but definitely good to keep it in mind when designing the chassis. Max. power dissipation of a 5mm LED such as http://www.farnell.com/datasheets/1911499.pdf, is less than 100mW.
Are you looking to use the pre-made encapsulated LED strips like these: 10/30CM 5050 LED STRIP LIGHTS RED GREEN BLUE DC12V TRAILER CARAVAN BOAT CAR | eBay
If they are straight forward dumb LEDs and not the fancy remote controlled flashing disco kind, then I don't think noise emissions will be much of an issue. Also tapping power and feeding it through it's own regulator circuit (like the one Michael posted) will be much quieter compared to powering it by a small (noisy) SMPS for instance.
You can always put an 'off' switch on the LED circuit to kill then when listening if it turns out they do generate more noise than you'd like...
How much heat is produced will depend on a few variables such as the type of LEDs you use, how many, the airflow arrangements of the enclosure etc. I wouldn't be tooworried out heat generation, but definitely good to keep it in mind when designing the chassis. Max. power dissipation of a 5mm LED such as http://www.farnell.com/datasheets/1911499.pdf, is less than 100mW.
Are you looking to use the pre-made encapsulated LED strips like these: 10/30CM 5050 LED STRIP LIGHTS RED GREEN BLUE DC12V TRAILER CARAVAN BOAT CAR | eBay
If they are straight forward dumb LEDs and not the fancy remote controlled flashing disco kind, then I don't think noise emissions will be much of an issue. Also tapping power and feeding it through it's own regulator circuit (like the one Michael posted) will be much quieter compared to powering it by a small (noisy) SMPS for instance.
You can always put an 'off' switch on the LED circuit to kill then when listening if it turns out they do generate more noise than you'd like...
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So the design is for a my buffalo dac that has been in a chassis I bought from AliExpress but it’s been getting just too hot. The psu’s run naturally hot but where I live in brisbane it’s just too much for me to be comfortable (it’s in a glass hall cabinet with fans but probably not enough). I was a 1/4 way through putting the dac in a case which would work quite well with a class a amp however I have since decided to put that case to a different use.
I’m entertaining the idea of a layered aluminium chassis with each layer rounded over. In between an undetermined number of aluminium layers I will have an acrylic layer with leds behind. If led heat is an issue there would be an aluminium layer surround by acrylic.
Each acrylic layer would have rgb leds like they do in pc cases these days.
Each aluminium layer would be thermally attached to each other with the psus attached to these as a heat sink. Should be plenty without factoring in the led heat dissapation.
Could I use a placid HD psu for the leds? Current is adjustable with the remainder of what’s used shunted and dissapated.
I’m entertaining the idea of a layered aluminium chassis with each layer rounded over. In between an undetermined number of aluminium layers I will have an acrylic layer with leds behind. If led heat is an issue there would be an aluminium layer surround by acrylic.
Each acrylic layer would have rgb leds like they do in pc cases these days.
Each aluminium layer would be thermally attached to each other with the psus attached to these as a heat sink. Should be plenty without factoring in the led heat dissapation.
Could I use a placid HD psu for the leds? Current is adjustable with the remainder of what’s used shunted and dissapated.
It would work if the current can be adjusted to the proper level for LEDs...but it would be way-overkill for the application. The circuit I posted is super simple, reliable, and a small footprint on a board but could be also easily be done "dead bug' style. Oh, and it too is adjustable with the remainder of what’s used shunted and dissipated.
Mike
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