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First x0xb0x, mostly noise :-(
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First x0xb0x, mostly noise :-(

by caponian on Sun Jan 19, 2020 6:03 am

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 137 times
x0xb0x_D35_env.png
x0xb0x_D35_env.png (51.45 KiB) Viewed 137 times
x0xb0x_BA6110_Pin6.png
x0xb0x_BA6110_Pin6.png (52.19 KiB) Viewed 137 times

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

Re: First x0xb0x, mostly noise :-(

by caponian on Sun Mar 01, 2020 2:34 am

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

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

Please be positive and constructive with your questions and comments.