Noise problem

  • i have problem with noise section no power on U24 like in yocto manual and i cant adjust it to 130 mV only 20- 30
  • I finished my board and all of the instruments sound alright except for the snare and clap. It sounds like the noise decay is too long and too distorted. I checked with my multimeter but it's around 130mv. However, it's not a proper meter.
  • It seems I fixed it. I replaced the trimmer with a 200k. Again, I don't have a proper meter, but things sound as they should.
  • I just finished the noise section but I have no power at the U24 like Bedroommusic mentioned. Did you end up fixing it? I have plus/minus 15v and ground at the supply bars next to the hihat section but not at the supply bars in the bassdrum section. Is that right? Also no continuity between +15V and U24 pin 8 or -15v and U24 pin 4. I followed the instructions and did the noise section straight after the sequencer parts required for the test mode. I'm assuming the 8 pin doesn't need to be connected and IC119 isn't required for the noise test.
  • Brownie_0403 wrote:I just finished the noise section but I have no power at the U24 like Bedroommusic mentioned. Did you end up fixing it? I have plus/minus 15v and ground at the supply bars next to the hihat section but not at the supply bars in the bassdrum section. Is that right? Also no continuity between +15V and U24 pin 8 or -15v and U24 pin 4. I followed the instructions and did the noise section straight after the sequencer parts required for the test mode. I'm assuming the 8 pin doesn't need to be connected and IC119 isn't required for the noise test.
    Hi did you make the Psu IO board and Psu Busses ( the big board) if not you will not have power on the big board because you didnt finish the power section :D
    on the individual voice parts is the PSU BUSSES PARTS ;)
  • Yes I figured that out after I posted and just completed the PSU bus and I tested and tuned the noise section successfully. Thanks for your feedback!
  • Did anyone get to a root cause on this issue? I can't adjust below 320mV. Should I just order a larger trimmer?
  • Replacing U24 with a TL072 and changing TM4 for a 100k got it to 130mV RMS. I could only get it to 160mV with the 4558 and the 100k trimmer.
  • I had the same problem, a 100k trimmer for TM4 got me to 130mV RMS. Now just a potentially faulty IC3 causing intermittent clap failure is my only remaining problem.