First x0xb0x, mostly noise :-(

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caponian
 
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Joined: Sun Jan 19, 2020 2:50 am

First x0xb0x, mostly noise :-(

Post by caponian »

Hello,

I have put together my first x0xb0x and I'm struggling with getting it up and running. From the output I get very faintly the tones from the oscillator and on top of that a very loud noise that seems to trigger each beat.

What I have tested so far:
  • Voltages from PSU are ok
  • VCO seems to work, scope looks fine
  • Filter probably ok... Tone at R46 fine. However, noise present at R72.
  • Noise present at C38 at VCA output
  • Voltages at BA6110 seem to be ok
  • Digital part seems to work fine
It seems like I'm hearing the envelope as loud noise somehow...

I have attached some scopes:
  • Ba6110, Pin 8
  • D35 (envolope out?)
  • BA6110, Pin6

How can I figure out whether the noise comes from the filter, the envelope or the VCA?

Any hint would be greatly appreciated!

Thanks,
Christoph
Attachments
x0xb0x_BA6110_Pin8_out.png
x0xb0x_BA6110_Pin8_out.png (48.8 KiB) Viewed 1889 times
x0xb0x_D35_env.png
x0xb0x_D35_env.png (51.45 KiB) Viewed 1889 times
x0xb0x_BA6110_Pin6.png
x0xb0x_BA6110_Pin6.png (52.19 KiB) Viewed 1889 times

User avatar
caponian
 
Posts: 2
Joined: Sun Jan 19, 2020 2:50 am

Re: First x0xb0x, mostly noise :-(

Post by caponian »

I have solved the problem and my x0xb0x is now working perfectly. It was a defective BA6110.

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