Wondom JAB3+ Input overload

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joe_dirt851

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Joined 2024
#1
Hello,

This is my first DIY project. I picked up the Wondom JAB3+, ICP5 programmer, etc. and I have had success connecting with SigmaStudio.

I have a problem with the board and volume. When I test using the supplied volume POT, and I turn the volume up to max, the board appears to overload, causes a red error light to come on and sends an awful "chirp" to the speaker before locking up entirely. I have to power cycle, then the board is back to running normally.

Has anyone had that experience? Is there something I can do in SigmaStudio to catch this before it happens? I understand the concept of a compressor and even set up a test program with one at the tail end of the workflow. The problem I am running into with the compressor is that the loudest volumes sound awful and I can hear the compressor kick in and out.

I've thought of putting in a dB reducer at the input side, but that just makes the top level volume too low.

Do I have a faulty board? Do I have to make changes in SigmaStudio? Anyone else have similar issues and was able to resolve?

Thanks,
Joe
 
#4
I would need details before attempting to diagnose your problem:

  • What specific model of JAB3+ do you have? 1 X 60, 1 X 100, 2 X 30, etc. The current 2 X 30 is at version 5. The Wondom SKU number would be great.

  • What power supply are you using? The voltage and maximum current for starters, a model number would be better.

  • What DSP program are you using? A link to it would be good or post it.

  • What speakers are you using?

  • Is the sound OK before the board overloads? How loud does it get before it overloads?

  • Does the problem occur with both BT and analog outputs? Just with one?

  • If using analog inputs what is the source?
The more information you can provide, the better.
 
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#5
Okay. Thanks all for the feedback. Here's what I've got.

BOM:
SigmaStudio Schematics:

Answers to your questions:
  1. Speakers are cheap. These are a test set that I don't care if I blow them out. I have also tested with some small bookshelf speakers: Samsung (PS-FQ70) and JVC (SP-THGF1F), same results.
  2. Sound is okay, but I'm using a cardboard shoebox as a temporary cavity to lay out the boards and simply play around. Building a decent box is down the road.
  3. Sound is fine as the POT is ramped up. No distortion until the entire AMP errors out, loud chirp, then nothing until reboot.
  4. Inputs: Line input (Laptop -> 1/8" cable -> JAB3+ board) or Bluetooth.
  5. Test Scenario:
    • Set inputs at max (on laptop and phone)
    • Set POT to zero
    • Start audio file
    • Turn POT up until error condition
Things I've tried to stop the issue. I start with the Stereo Demo schematic above:
The issues appear to be more related to low end frequencies. I have tried with a selection of music (Rap, Heavy Metal, EDM) where there is a clear singal change (i.e. the "drop" in EDM). And it is consistently at that point where the board errors out. I added a signal monitor (https://wiki.analog.com/resources/t...detectorslookuptables/singlebandleveldetector) and I can see the level register up to the point of error.

I tried to use the gain reducer and compressor to hard limit of roughly -14db, which "sort of" works, but then the overall level hardly fills the near field space (< 6ft.). Pretty pointless to build a shelftop system that you have to hold up to your ear. Second to this is that I play the input on loop and the same music file played multiple times could be fine, but then randomly during one of the replays it errors out.

Thanks again for all the help!
Joe
 
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