Has anyone any thoughts on whats going on here.
Filter resonating itself signal going though to output, filter has no effect on it.
Made a quick video, can’t figure how to upload it.
When I make a video on my cheap smartphone I upload it to YouTube as “unlisted.” Uploading is easy, just use the Share option in Google Photos and select YouTube from the “share to apps” list.
Then I can post a link to the video in this forum and it embeds automatically.
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Thanks for that!
I get “video unavailable” from that.
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Any comments on this vid?
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I’ve fiddled with the trim pot on the back and it seems to resonate but with a low range.
Sorry. Not wearing that head today. I’ve bookmarked it for tomorrow when im likely to be less sedate.
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Check voltages on all IC power pins (see datasheets). Any ICs running hot? Which controls affect outputs (and how), which don’t have any effect? Examine solder joints and reflow any that look dodgy.
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yep analogoutput that is good add vise . I will do the heat test on IC’s , voltage regulators first thing on plugging in a new built module . if they are hot to the touch chances are you have a sort somewhere . immediately unplug and look for solder bridges , backwards parts etc. . and as we find here more often than not the problem is a bad solder joint somewhere . then there is the tedious task of checking to make sure you have the right components / values in the right places . when I put components on the boards I put matching components facing the same way , like the stripes on resistors or writing on caps it makes identifying them easier when trouble shooting . it is frustrating but you will eventually find the little thing that is the problem .
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Filter Res High Pitch Screech, latching LEDs?
anybody come to a conclusion what could make some filters do this ? i have two filters built now, the second one i built showed me my first filter is not quite right, as the second one sounds amazing, like it should, but the first one i built sounds similar to the video above by “dufrok” as in loud screech from the res, latching leds rather than osc back n forth, my filter functions but the res is not pleasant to the ears. sounds over driven and high pitched, will easily peak and then cut out to a static sound when turned up above 2/3. i moved the trim pot to the front panel so i can dabble there but i cannot come to terms with the screech. if i trim down i get to a point where the screech cuts off all together. i can post a video of this shortly. I have replaced all the resistors as many were not the right wattage with no change, so i fixed all the jumbo resistors and replaced many caps on spec (1nf,100nf x’d) and re-soldered all points both side of the PCB. I measure the filter pot and watched as i turn to look for irregularities. none found. Everything functions, is just not a good sounding resonance unless you like dog whistles.
im going to change the pots on spec next and maybe swap the LM when another comes in. So far my strategy is replace all components one x one till i find it 
lol
Thoughts?
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