The area between the Flow wire/trace and the Return wire/trace.
Each inter-module connection is made with TWO wires.
The Flow and Return (hot & cold).
The gap between them creates a loop area and that loop area is an aerial.
Big loop areas = big emi.
Twisting swaps the loop areas into opposing fields and helps cancel the loop area effect.
ok, this might be a very stupid question:
the speaker connectors are not marked on the pcb. does it matter which one goes to the black speaker connection and which one goes to the red?
the speaker connectors are not marked on the pcb. does it matter which one goes to the black speaker connection and which one goes to the red?
Normally you would connect J1-2 (round pad on PCB) to the red and J1-1 (square pad on PCB) to the black speaker terminal.
I would be really surprised if this is not in the documentation.
I would be really surprised if this is not in the documentation.
Did you solder the IC pins before or after installing the heat sink clips?drilling and tapping done 🙂
ESP is a superb free resource.
But go look at the heatsink manufacturers' application notes.
At the geometric centre is wrong.
Look at post202. He has got very close to optimal placement.
Slightly wider apart would be better, but I suspect I don't have the resources to measure any improvement.
His height looks about perfect, i.e. 25% up from the bottom.
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Can you give me a link to look at please? I've looked https://www.fairchildsemi.com/application-notes/AN/AN-4166.pdf
http://www.ti.com/lit/an/slva462/slva462.pdf
https://www.infineon.com/dgdl/an-1057.pdf?fileId=5546d462533600a401535591d3170fbd
can't find anything specific to placement, thanks
http://www.ti.com/lit/an/slva462/slva462.pdf
https://www.infineon.com/dgdl/an-1057.pdf?fileId=5546d462533600a401535591d3170fbd
can't find anything specific to placement, thanks
Thanks to all your help and the quick replies I was able to finish building the amp last night .... well the test setup anyways. It works 🙂. And I'm very happy to have successfully built my first amp. Thanks for your support!
A few observations:
I wasn't sure if there would be enough gain to use it with my phono pre-amp without adding another preamp. Well, it works just fine. I use a 50k pot and that seems to be a good choice as well (I don't have any comparison obviously).
The heat sink seem to be of the right size. I don't have a thermometer at hand but it doesn't even get warm .... probably around body temperature as it just feels "neutral".
I do have some noise / hum issue. There's hum when I connect it to my phone pre. The hum disappears when I touch the casing of the phono pre and the pot of the lm3886 at the same time. Is there an explanation for that?
There's some noise even if no source is connected at all. Its rather high pitched and coming from the tweeter. Sounds kind of like holding a mobile phone close to a radio.... just not as loud. Actually it isn't very loud at all but I'd still like to get rid of it. But then again the whole setup isn't properly grounded yet, the wires are not bundled up, etc. So maybe it will just disappear.
For now I'm just very happy with my new amp!
A few observations:
I wasn't sure if there would be enough gain to use it with my phono pre-amp without adding another preamp. Well, it works just fine. I use a 50k pot and that seems to be a good choice as well (I don't have any comparison obviously).
The heat sink seem to be of the right size. I don't have a thermometer at hand but it doesn't even get warm .... probably around body temperature as it just feels "neutral".
I do have some noise / hum issue. There's hum when I connect it to my phone pre. The hum disappears when I touch the casing of the phono pre and the pot of the lm3886 at the same time. Is there an explanation for that?
There's some noise even if no source is connected at all. Its rather high pitched and coming from the tweeter. Sounds kind of like holding a mobile phone close to a radio.... just not as loud. Actually it isn't very loud at all but I'd still like to get rid of it. But then again the whole setup isn't properly grounded yet, the wires are not bundled up, etc. So maybe it will just disappear.
For now I'm just very happy with my new amp!
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Nope, still no luck, I conclude that it must be very low on the list of priorities of correct heatsink application, it is section 14 in Rod Elliott's article after all
Try as I might I can't find any information about the convection of heat in aluminium, I'm confused, can someone point me in the right direction please?
tried AAvid and Fischer, but the info must be buried too deep.
You could try this
HeatSinkCalculator
there is another that has been linked on this Forum a few times.
You could try this
HeatSinkCalculator
there is another that has been linked on this Forum a few times.
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It sounds like interference and maybe ground loops. You seem to understand the issues, an enclosure and correct grounding will cure them
will an enclosure act as a farady cage and help prevent noise from radio frequencies, wlan, mobile phones etc.?
thanks, scottjoplin!
i need to move the led to the front of the enclosure so i can have an "on light". I've never worked with LEDs before so I have no idea how to do that.
would something like this work? I could just cut off the end with the plug and attach it to the screw terminals on the PCB. Will any 5mm LED fit in the other end? any other suggestions?
LED Cable
i need to move the led to the front of the enclosure so i can have an "on light". I've never worked with LEDs before so I have no idea how to do that.
would something like this work? I could just cut off the end with the plug and attach it to the screw terminals on the PCB. Will any 5mm LED fit in the other end? any other suggestions?
LED Cable
The SMPS-86 already has an ON-indicator. Just move the LED to the front panel of your chassis. Take note of which pin is which (anode, cathode) and cut them to 5 mm length from the body of the LED. Solder wires onto the pins and connect these to the terminal block on the SMPS-86.
The cathode (-) is the short lead. It is marked by a flat on the LED package.
Tom