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Post by dizzeesatchel on Aug 27, 2023 16:09:59 GMT
A couple of people have noted that AEuroPi can introduce a pretty loud background noise under some circumstances, especially when using the HP AMP module or the headphone output built into POWER 
My poor understanding of power filtering is to blame here, but it should be fairly straightforward to alleviate in future designs. In the meantime if you're handy with a soldering iron you can greatly reduce the background noise with a few components:
- 10ohm resistor - electrolytic capacitor rated for at least 10v & 100uf, a greater uf value would probably be even more effective - short bit of shielded wire - solder, and desoldering braid or a solder sucker
Desolder the top end of the diode (the end with the stripe) and lift that end out of the PCB
Solder the now-exposed end of the diode to one end of the resistor, and put the other end of the resistor through the hole where the diode was removed
Take your capacitor and place the positive leg (the longer one) through the same hole as the resistor. Then solder them both into place.
Solder one end of a strip of wire to the negative (short) leg of the capacitor, and carefully solder the other end to one of the ground pins coming through from the bus cable (take care to avoid the 5v pins which are immediately above)
All done!
You'll need to bend the capacitor over to lie flat so it fits under the front panel. Double check nothing is making contact with any of the other components. I taped things into place with kapton tape as an extra precaution.
Here's a little diagram and some photos of the finished arrangement
There's still some audible noise on the menu screen (funny that, Ornament & Crime is also noisiest when using the menu) but it's WAY improved, and with a script running it's close to noiseless on my headphones.
As for whats coming up, i have a handful of boards from a test of the most recent version, so i may manually install the power fix on these and make them available as B-stock. Then hopefully another larger run, if desired  The new versions are nice if you like blinkenlights...
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julientaq
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designing stuff with html and css
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Post by julientaq on Aug 28, 2023 8:40:58 GMT
in the serie “i know nothing”. Would a 16v 100 uF would work?
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Post by robertlanger on Aug 28, 2023 8:58:30 GMT
in the serie “i know nothing”. Would a 16v 100 uF would work? YES! The voltage is a maximum rating, if it is specified higher, it's never a problem (except the part is bigger then) |
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Post by robertlanger on Aug 28, 2023 9:00:07 GMT
Yes, these OLED displays introduce a lot of noise; on the SAMPLYR module, I had added a separate small resistor and 47uF capacitor filter only for the display ;-)
Indeed, the HPAMP and POWER modules headphone outs are quite sensitive to supply noise; in a new design, I have swapped the driver chip which should be better. BTW, FYI: In a new version of the POWER module, the headphone out will be stereo, and also stereo in/outs, so 4 channels in total! Release in near future.
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Post by admin on Aug 28, 2023 9:02:01 GMT
Phew ... I'm so glad I haven't started my build yet  Now to find those components... |
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julientaq
New Member
designing stuff with html and css
Posts: 14
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Post by julientaq on Aug 28, 2023 9:06:28 GMT
Awesome.
Thanks!
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Post by dizzeesatchel on Aug 28, 2023 9:46:32 GMT
in the serie “i know nothing”. Would a 16v 100 uF would work? YES! The voltage is a maximum rating, if it is specified higher, it's never a problem (except the part is bigger then)
yes in my earliest days of DIY-ing i needed 470uf caps but accidentally bought a bunch rated for 50v... they were huge!
Sorry for the inconvenience everyone!
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Post by tIB on Aug 28, 2023 10:38:18 GMT
Yes, these OLED displays introduce a lot of noise; on the SAMPLYR module, I had added a separate small resistor and 47uF capacitor filter only for the display ;-) Indeed, the HPAMP and POWER modules headphone outs are quite sensitive to supply noise; in a new design, I have swapped the driver chip which should be better. BTW, FYI: In a new version of the POWER module, the headphone out will be stereo, and also stereo in/outs, so 4 channels in total! Release in near future. Ooh that's interesting - will the new power module provide any more juice/ma or is it the same specs? |
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Post by dizzeesatchel on Aug 28, 2023 12:07:16 GMT
Yes, these OLED displays introduce a lot of noise; on the SAMPLYR module, I had added a separate small resistor and 47uF capacitor filter only for the display ;-)
I'm going to borrow this trick too
So improving the power filtering to the Pico as above makes a big difference. The other 5v pin from the bus cable goes to the op-amps (and pots), would it be advisable to put an RC filter on this power line too, or does that risk dropping the voltage to the op-amp and messing up the scaling? There's already a small capacitor only (100nf) between power and gnd right next to each op-amp. edit: better picture of the fix layout, this is how i'll be setting up the spare unbuilt boards I have:  |
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Post by robertlanger on Aug 29, 2023 11:49:43 GMT
Yes, these OLED displays introduce a lot of noise; on the SAMPLYR module, I had added a separate small resistor and 47uF capacitor filter only for the display ;-) Indeed, the HPAMP and POWER modules headphone outs are quite sensitive to supply noise; in a new design, I have swapped the driver chip which should be better. BTW, FYI: In a new version of the POWER module, the headphone out will be stereo, and also stereo in/outs, so 4 channels in total! Release in near future. Ooh that's interesting - will the new power module provide any more juice/ma or is it the same specs? It's unchanged regarding the power, and it's basically the same as MASTER, so with the standard wall adapter, it should be fine for 800mA...1A |
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julientaq
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designing stuff with html and css
Posts: 14
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Post by julientaq on Aug 29, 2023 19:28:52 GMT
Made the fix. quite fun (my board is officially a mess, but it works  ) Thanks for saving my hears |
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Post by rockysmalls on Aug 29, 2023 21:25:31 GMT
Yes, these OLED displays introduce a lot of noise; on the SAMPLYR module, I had added a separate small resistor and 47uF capacitor filter only for the display ;-) Indeed, the HPAMP and POWER modules headphone outs are quite sensitive to supply noise; in a new design, I have swapped the driver chip which should be better. BTW, FYI: In a new version of the POWER module, the headphone out will be stereo, and also stereo in/outs, so 4 channels in total! Release in near future. i couldn’t just ‘like’ this , i love this!! i have a ‘bit’s & bobs’ order brewing... how ‘near’ is The Future?? |
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Post by funbun on Aug 29, 2023 21:49:57 GMT
So, will this get fixed in a future PCB?
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Post by dizzeesatchel on Aug 29, 2023 21:54:16 GMT
Definitely! I already have a revised PCB designed, will order some soon and put them through some tests (you know how it can be, you fix one thing and it breaks another...)
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Post by robertlanger on Aug 30, 2023 9:43:00 GMT
Regarding the revised POWER module: I received the prototype PCB yesterday; if no serious errors are in, the module should get released in a few weeks. Only "problem": I'm currently in a private move, which demands a certain amount of time...  |
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Post by rockysmalls on Aug 30, 2023 13:56:17 GMT
Regarding the revised POWER module: I received the prototype PCB yesterday; if no serious errors are in, the module should get released in a few weeks. Only "problem": I'm currently in a private move, which demands a certain amount of time... i hope your new place brings tremendous happiness.... and of course great inspiration for the future. |
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Post by tIB on Sept 12, 2023 20:25:54 GMT
I encountered the noise thing tonight after pulling my patch apart to fit a new module...
Can I just check that the fix is as posted in the OP and there's nothing else to do? I'll give you a shout if I feel I've bitten off more than I can chew...
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Post by dizzeesatchel on Sept 12, 2023 23:04:39 GMT
I encountered the noise thing tonight after pulling my patch apart to fit a new module... Can I just check that the fix is as posted in the OP and there's nothing else to do? I'll give you a shout if I feel I've bitten off more than I can chew... Yep, everything needed is outlined in that first post. I'm about to order a new batch with fingers crossed much improved power filtering as standard, so worst case scenario - if you really come unstuck - i'll make it right
What did you change in your patch which made the difference out of interest?
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Post by tIB on Sept 13, 2023 5:13:04 GMT
I encountered the noise thing tonight after pulling my patch apart to fit a new module... Can I just check that the fix is as posted in the OP and there's nothing else to do? I'll give you a shout if I feel I've bitten off more than I can chew... Yep, everything needed is outlined in that first post. I'm about to order a new batch with fingers crossed much improved power filtering as standard, so worst case scenario - if you really come unstuck - i'll make it right
What did you change in your patch which made the difference out of interest?
That's great, thanks - fingers crossed I should be fine with the fix. It's not so much that a difference was made, more that I was able to listen to the noise in an unpatched system and add/remove the pi. And I'll still have noise after the fix from other modules, such is the nature of ae, but I'll have a little less! Edit: oh, and I added a replacement (and always quite noisy!) TBD to the rack. |
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Post by tIB on Sept 14, 2023 8:27:53 GMT
That's a fix! Thanks for the info.
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Post by dizzeesatchel on Sept 22, 2023 21:23:20 GMT
updates!
first version vs. hacked fix version vs. new version with tons of filtering built in! edit: just to be clear, this is audio recorded from the POWER headphone out. the standard line audio outputs don't seem to pick up this noise at all.
perfect? not quite. as good as my dubious electronic skills will allow? probably!
so in the last version i tried surface-mount LEDs and they kind of sucked. i got a bunch of these old Mutable Instruments leds which Thonk are selling off. they're baby pink, and turns out they're incredibly bright! Maybe too bright actually. Anyway the good news is we should be going back onsale soon, with LEDs of one colour or another |
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Post by tIB on Sept 22, 2023 21:38:05 GMT
updates!
first version vs. hacked fix version vs. new version with tons of filtering built in!
perfect? not quite. as good as my dubious electronic skills will allow? probably!
so in the last version i tried surface-mount LEDs and they kind of sucked. i got a bunch of these old Mutable Instruments leds which Thonk are selling off. they're baby pink, and turns out they're incredibly bright! Maybe too bright actually. Anyway the good news is we should be going back onsale soon, with LEDs of one colour or another You've just given me a really good idea... get another! (Edit: to be clear I mean to run a second firmware - nothing to do with the noise aspect!) |
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Post by solipsistnation on Sept 23, 2023 4:23:17 GMT
Soooo uh..
You got a Roundabout in AE format in there?
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Post by dizzeesatchel on Sept 23, 2023 10:05:15 GMT
Heh, kinda... it's literally just a roundabout screwed into the rack, the faceplate makes it look like more of a real thing, but i just threw that together to stop it getting dusty |
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Post by solipsistnation on Sept 23, 2023 16:49:25 GMT
Oh okay. It looks pretty nice. 8)
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Now to find those components...
)
