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| Richard Crowley:
--- Quote from: 001 on November 29, 2018, 03:37:47 pm ---But why 5kHz? --- End quote --- Why not? You can design an SMPS to operate at ANY sub-sonic, sonic, or super-sonic frequency. If you were designing some non-audio product, there is no reason to avoid sonic frequencies. Just your bad luck to be within the field of something that wasn't designed for audio environments. That is why it will require more extensive detective work to identify the source with some sort of portable "probe". |
| 001:
--- Quote from: Richard Crowley on November 29, 2018, 06:12:21 pm --- --- Quote from: 001 on November 29, 2018, 03:37:47 pm ---But why 5kHz? --- End quote --- Why not? You can design an SMPS to operate at ANY sub-sonic, sonic, or super-sonic frequency. If you were designing some non-audio product, there is no reason to avoid sonic frequencies. Just your bad luck to be within the field of something that wasn't designed for audio environments. That is why it will require more extensive detective work to identify the source with some sort of portable "probe". --- End quote --- Is some spetial grounding can help me? I rotate pickup and now I find "quiet" position But now I can hear some chirping and new HFhum :-// (dont worry about mains buzz) Hear it: |
| tggzzz:
--- Quote from: 001 on November 29, 2018, 06:37:28 pm ---Is some spetial grounding can help me? --- End quote --- Have you read the reference I provided here: https://www.eevblog.com/forum/projects/need-help-with-emc-problem-and-audio/msg1990748/#msg1990748 Full of good theory and practice |
| ogden:
--- Quote from: 001 on November 29, 2018, 06:37:28 pm ---Is grounding can help me? --- End quote --- You shall find issue first, only then fix it. I would switch off anything in that house except guitar+amplifier+recording_laptop_on_batteries and check that interference is gone or not. If not then find it. After all it is *audible* frequency, you have "EMC receiver" in any device with microphone input. Find some solenoid or build one and go hunting. To find junk SMPS, I usually suggest LW/AM radio. Pure 5KHz sine w/o harmonics is strange interference, dunno if radio receiver could help, yet you can try if have such in your toolbox. |
| 001:
--- Quote from: ogden on November 29, 2018, 06:57:03 pm ---Pure 5KHz sine w/o harmonics is strange interference --- End quote --- Yea! What gear use it? |
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