Speaker crackles, but only for swings

This meaning if PWM is used for accents?

No, any times the FETs are used for anything, the 5v is running to make sure Vgs doesn’t go too low.

Finally got around to actually listening to the video.
I don’t think it’s caused by the SD card.
Speaker, amp or 5v supply are possibilities, but the fact that it still crackles at low volumes speaks against that. I did use to have a speaker that sounded sort of like this though. It had an metal cone with a large divot in. I think maybe I had dropped onto something…

Does the serial monitor say anything interesting?

Nope. Serial monitor output is completely normal.

And is the volume as low as your config file says?
(What does the “get_volume” command say in the serial monitor?)

How many ohms is the speaker?

4 ohm speaker. get volume shows 800.

07:55:29.026 -> 800
07:56:48.225 -> EVENT: Power-Shortclick millis=67679150
07:56:48.225 -> Ignition.
07:56:48.263 -> unit = 0 vol = 0.00, Playing GREEN/hum01.wav
07:56:48.263 -> channels: 1 rate: 44100 bits: 16
07:56:48.263 -> unit = 1 vol = 0.50, Playing GREEN/out01.wav
07:56:48.263 -> channels: 1 rate: 44100 bits: 16
07:56:48.263 -> humstart: 1800
07:56:48.263 -> unit = 2 vol = 0.00, Playing GREEN/swingl01.wav
07:56:48.263 -> channels: 1 rate: 44100 bits: 16
07:56:48.263 -> unit = 3 vol = 0.00, Playing GREEN/swingh01.wav
07:56:48.301 -> channels: 1 rate: 44100 bits: 16
07:56:49.657 -> unit = 2 vol = 0.00, Playing GREEN/swingl01.wav
07:56:49.657 -> channels: 1 rate: 44100 bits: 16
07:56:49.657 -> unit = 3 vol = 0.00, Playing GREEN/swingh01.wav
07:56:49.657 -> channels: 1 rate: 44100 bits: 16
07:56:49.924 -> EVENT: Swing ON millis=67680838

I’m going to replace the speaker wires with something a bit heavier and I think I might rewire the bulk of it for shorter wiring. I initially thought the customer (who lives up the street, so really is just a friend who is getting a free build) would be pickier about the buttons and such so I thought I’d need more slack than I do for disassembly.

The speaker wires go right next to the battery switch, so maybe it’s interference?

Rewired the speakers, went 26awg for total overkill… still doing it. If I give the board enough wiring slack that i’m only moving the board and not the saber, it still does it. Connections to the board are all very solid, so it seems like it has to be the board, but I’m not sure if there’s a way to further diagnose. I certainly don’t see anything odd in my config. I’m at a loss.

You could always try the connecting the speaker and SD card to a known working ProffieBoard. If you do that and there isnt a crackle, you will know its the boards fault.

Also; That is a PRETTY saber! Shame that you are having issues.

I did the inverse - I connected a known good speaker and SD to it. I’ve also changed the ground point from one side of the board to the other. Nothing. There’s a clicking noise you can hear when it’s just sitting running an idle hum as well that makes me think it’s the amp. I’ll upload a video.

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Right, I did read that, my fault.

Yeah, it does seem like its a board issue, though Im certainly no expert.

Here you can hear it clicking just sitting there playing idle hum.

@profezzorn if you have any ideas about something else to check i’m all ears, but I’m assuming I’m just basically humped at this point. seems like a bad amp and i don’t imagine it’s something I can just fix.

I’m wondering if maybe we’re hitting some protection circuit in the amp. Since we push the amp pretty close to it’s limits, this could happen if either the speaker is in fact lower than 4 ohm, or if the amp is just a bit out of spec. If that’s the case, a reasonable solution might be to add a small resistor (1-2 ohms) in series with the speaker. (And possibly push the volume a bit higher to compensate.)

If this doesn’t help, I might be out of ideas for how to fix this.

Is that clicking rhythmic? I distinctly hear a repeated pattern there, not random. 2 slow quiet clicks, 2 loud quick, repeat.

It’s only rhythmic in that video. It’s not normally.

Still, a distinct repeat of a pattern, even once (I’d venture to bet it does it more often than you’ve noticed) would indicate a cycle of sorts, something resetting or initializing or shutting down over and over, as opposed to completely random source.
Just a clue possibly, that’s all.

Swapping the board definitely did the trick.

@profezzorn if this is something you want to do a postmortem on let me know and I can mail it your way. If not I’ll try the resistor trick. If it doesn’t work I guess I’ve got another test rig board. ¯_(ツ)_/¯

I would be interested in hooking up the 5v pad to an oscilloscope and see how well it fares. This could tell me if the problem is with the amp itself, or if it’s the 5v input that is not working well.

PM me your address and I’ll send it your way then. If I use it for anything it’ll be another boxxie and I’m not in a rush to build another of those.