I'm building my 2nd class D amp, this time in a more "official" aluminum case.
I need to start thinking on what piece goes where - where to put the SMPS, where to put the Amp board, where to put the DSP board, and then how to wire it all up.
Is there any info available like "This shouldn't be near that, never pass this cable in proximity of that specific thing/cable, never cross these types of cabling" and so on?
I'm looking for guidance to avoid making easily preventable mistakes..
I need to start thinking on what piece goes where - where to put the SMPS, where to put the Amp board, where to put the DSP board, and then how to wire it all up.
Is there any info available like "This shouldn't be near that, never pass this cable in proximity of that specific thing/cable, never cross these types of cabling" and so on?
I'm looking for guidance to avoid making easily preventable mistakes..
When high frequency switching is involved, EMC is an important issue to consider.
Just simply said how electromagnatic compability is involved:
Two entities, mutual interference - wanted and unwanted, promote the first, avoid the second.
Two paths only, conduction or-and radiation, wires or wizardry.
Untangle, distance, decouple, shield, close-the-loop, soberness.
Put your smart phone on your radio (if you have one...), and then carry it away.
Just simply said how electromagnatic compability is involved:
Two entities, mutual interference - wanted and unwanted, promote the first, avoid the second.
Two paths only, conduction or-and radiation, wires or wizardry.
Untangle, distance, decouple, shield, close-the-loop, soberness.
Put your smart phone on your radio (if you have one...), and then carry it away.
The previous one is completely different from my next and had much more room to keep things separated, so it's not really relevant here..
That aside back then I put it in a sealed enclosure so I can't open it up again to take photos :-D
(Wont be doing that again :-D)
I'll take some pics tonight of the current build parts to show how I need to puzzle them to fit in the small alu case.
Thanks, this looks like what I was looking for!
I'll have a read tonight, see if I can wrap my head around it.
So here's the issue - the parts I eventually ordered were bigger than the parts I had in mind when I started this project (and bought the case), so it's very tight.
I think I can make it fit - I might have to desolder the RCA connections from the amp board (no problem, did something alike for my previous amp), but still - the 220v mains will be coming in pretty close to one output channel of the amp board (no idea whether that's bad), and I might even have to make an extra layer above the amp board to attach my (not pictured) Dayton DSP board.
Any tips on tight fitting builds are very welcome 🙂
I think I can make it fit - I might have to desolder the RCA connections from the amp board (no problem, did something alike for my previous amp), but still - the 220v mains will be coming in pretty close to one output channel of the amp board (no idea whether that's bad), and I might even have to make an extra layer above the amp board to attach my (not pictured) Dayton DSP board.
Any tips on tight fitting builds are very welcome 🙂
Can either of the boards be rotated, or made vertical? I wouldn't try to add a third board in there.
If you aren't using the two large heat sinks, it may be best to save this chassis for future use
(or sale), and get another one that is wider and/or longer.
If you aren't using the two large heat sinks, it may be best to save this chassis for future use
(or sale), and get another one that is wider and/or longer.
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Rotating them won't make it fit, I can either put the amp in back and SMPS in front or vice versa...
The DSP board is very small, 5x5cm, and I do have some height play in this chassis. So I could make a construction where the DSP is like 2cm above the amp board's heatsink, and it wouldn't obstruct (airflow) very much due to its small size relative to the amp board / heatsink. That would also get it close to the RCA audio input I need to make on the back of the amp, and the DSP's outputs would then also be near the RCA inputs of the amp board - just a few cm above them.
I'm keeping in mind this amplifier won't be pushed for club-volume-levels, it'll be used at casual / background listening volumes only.
I planned to put the DSP board in the empty bottom left area in the photo, but the thing with the DSP board is it has an extension board on top for easy connecting (using f.e. RCA), and actually using those makes it a bit too wide in total to fit in that space..
As this is a hobby / test project I don't want to buy another chassis, I'd rather go ahead and try different solutions to see whether it works.
If in the end it turns out it all doesn't work, another chassis will surely be an option.
But let's first see empirically what I can get away with 😛
I'm not looking for audio nirvana, for now I'm looking to just build with what I have in the best way given the less than optimal circumstances.
And then when the project is "done", phase 2 will be "alright, now let's see how I can fix it / do it better next time" ;-)
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Keep the SMPS close to the power socket, could fit vertical next to that socket. Amp board to front and DSP mounting mid air above. Stray fields from the SMPS catched with a (metal) separator. Noise filters in mains and in the power lines (ferrites).
If that's the main switch on the front, use shielded mains cable to wire it.
Edit:
There's a green terminal block in the upper left corner of the SMPS. How are you going to do that?
Are there tropical grade caps in that SMPS? If not, replace them now.
If that's the main switch on the front, use shielded mains cable to wire it.
Edit:
There's a green terminal block in the upper left corner of the SMPS. How are you going to do that?
Are there tropical grade caps in that SMPS? If not, replace them now.
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Cheers for replying, I'm trying to parse your info as good as I can 🙂
If I put the SMPS in the back next to the 220v (where the audio input / output connectors are near as well), I have to put the amp in the front.
That means I have to run longer line level signal cables from the back of the case to the front (passing the SMPS).
I thought I had to keep the line level signal cables as short as possible - try to keep the DSP at the back near the RCA input, keep the signal cables from the DSP to the Amp as short as possible.
That's why I figured having the amp and dsp as close to the back of the case as possible, and put the SMPS in front - 15cm of 220v to the SMPS, SMPS output back to the Amp in the back.
Can you - gently 🙂 - explain why it's better to have the SMPS in the back, and route longer line level input cables to the front where the amp would then be?
Also - I am clueless about your "tropical grade capacitors" remark.
The SMPS I'm using is the connex SMPS600RS : SMPS600RS | Connex Electronic
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