Totally forgot about them... screw-holes have been added. (M3)
Not for the AMP though, since for one there is very little space, and I also think the heatsink will keep it tightly in place. I know I know it's not 100% clean this way, but this way there is nearly no stress between the chip-pins and the board.
PSU+:
Not for the AMP though, since for one there is very little space, and I also think the heatsink will keep it tightly in place. I know I know it's not 100% clean this way, but this way there is nearly no stress between the chip-pins and the board.
+1
PSU+:
An externally hosted image should be here but it was not working when we last tested it.
It may depend on what the screws you use look like, how big the heads on them are, but the holes look a little close to R1/R2. You might gain a little space there if you moved C7/C8 up to right under the output connector, extending the ground trace down and over to both rail traces for placement of those. You could gain even more space at the bottom by moving the RC snubbers to that area too but then your C3/C6 capacitors would start to wall off the output connector more, making it more fiddly to connect and disconnect later.
Unless using very thin PCB material I doubt you'll need a screw hole in the middle, though if the output connector is a tight fit and requires a lot of force to plug into and unplug, the extra reinforcement is a good idea.
Unless using very thin PCB material I doubt you'll need a screw hole in the middle, though if the output connector is a tight fit and requires a lot of force to plug into and unplug, the extra reinforcement is a good idea.
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The key to that is if the cap is large enough, and Fc is low, it's going to be a dead short at any reasonable audio frequency, so it won't have any voltage across it and polarity doesn't matter. I personally try to avoid using them whenever I can, but you have to be aware of all the problems that could arise if you don't.
Mike
Mike
^ How would it be any shorter traces, unless using fewer capacitors or putting the PSU subcircuit on the amp board itself? You could combine the two ground traces but I would also aim for low resistance, by using wider traces as I mentioned previously but that can be done without any major layout changes.
This conversation has brought up another issue I'd overlooked. From what I remember, hurtz is designing the amp board for one LM3886 per board, which means there will need to be two amp boards for stereo use, two wires coming from both the positive, and the negative rails to handle both amp board but the PSU board connector appears to only allow for one wire connection per rail... so it would require one PSU board for every amp board as is.
This conversation has brought up another issue I'd overlooked. From what I remember, hurtz is designing the amp board for one LM3886 per board, which means there will need to be two amp boards for stereo use, two wires coming from both the positive, and the negative rails to handle both amp board but the PSU board connector appears to only allow for one wire connection per rail... so it would require one PSU board for every amp board as is.
I feel compelled to repeat what I posted in #90, to be sure there is no potential for ground loops, you really should at minimum keep the high level and low level grounds totally separate. You might get away with combining the power and speaker grounds, but to use a single conductor for all grounds from the amp board to the power supply is inviting disaster. Even if you have a "star ground" on the amp board, you're still using one wire to connect it back to the power supply, combining low level and high level signals. I have the input, power and speaker grounds all on thier own conductors, never have any issues. Besides, like I said before, wire is cheap and it's easy to do it that way.
Mike
Mike
As AndrewT/discrete explained some time ago, the RCRC-filter propertiesare actually worth keeping.
"Stereo" output-terminals have been added.
Star ground is now on the amp board itself, so only one common ground.
@Mike I know what you mean, but the trace-length between the AMP and the board is very short anyway, and then again I would wait for the test results to see how it goes.
cheers!
"Stereo" output-terminals have been added.
Star ground is now on the amp board itself, so only one common ground.
@Mike I know what you mean, but the trace-length between the AMP and the board is very short anyway, and then again I would wait for the test results to see how it goes.
An externally hosted image should be here but it was not working when we last tested it.
cheers!
Hi folks,
I just got feedback from enzoR about the test results which are compared to the p2p pretty much the same. To directly quote the speaker-grounding issue: "Grounding the speaker - on the amp board or on the powersupply made hardly any difference."
There will be some more detailed test results when enzoR comes back I think.
For now I'd like to publish the final version of the amp or rather the release version 1.0.
Thank you all for your friendly support and most helpful explanations!
The official names are:
"no11 AMP" and "PSU+"
cheers!
DIYing is strongly encouraged, but please let me know how it went! If you are interested in buying a kit/assembled/PCB let me know as well!
A parts-list will follow!
I just got feedback from enzoR about the test results which are compared to the p2p pretty much the same. To directly quote the speaker-grounding issue: "Grounding the speaker - on the amp board or on the powersupply made hardly any difference."
There will be some more detailed test results when enzoR comes back I think.
For now I'd like to publish the final version of the amp or rather the release version 1.0.
Thank you all for your friendly support and most helpful explanations!
The official names are:
"no11 AMP" and "PSU+"
cheers!
DIYing is strongly encouraged, but please let me know how it went! If you are interested in buying a kit/assembled/PCB let me know as well!
A parts-list will follow!
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