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  1. Maglatron

    Sallen Key Low Pass Filter, bandpass filter

    going to have the board to inspect for an hour or so, so then I can determine if it is "fudged" or not wish me luck
  2. Maglatron

    Sallen Key Low Pass Filter, bandpass filter

    thank you for the resistor chart. I have swapped out 8 of the 11 caps that were wrong but I think I fudged the pre-amp and amp part may have to rebuild, I do have the parts though so it's a minor set back we will see when all the caps are replaced and the on switch is flicked! I've got more of...
  3. Maglatron

    Sallen Key Low Pass Filter, bandpass filter

    so the parts have arrived at the sorting office so may get them today, fingers crossed!
  4. Maglatron

    Sallen Key Low Pass Filter, bandpass filter

    film is fine!!
  5. Maglatron

    Sallen Key Low Pass Filter, bandpass filter

    so bought these they're coming tomorrow hopefully! when I swap out the 10nF ones for these 100nF ones, it will look as though nothing's changed in the new photos but I'm hopeful that the circuit works and the bar graph LED's responds to sound!
  6. Maglatron

    Sallen Key Low Pass Filter, bandpass filter

    exactly like that lol
  7. Maglatron

    Sallen Key Low Pass Filter, bandpass filter

    yep I measured both sets that I thought were 100nF and they are infact 10nF!! doh palm hits forehead! but the positive is that I got to use the capacitor testing function on one of my multimeters! :) feeling silly
  8. Maglatron

    Sallen Key Low Pass Filter, bandpass filter

    got the new ones ordered now coming monday!!
  9. Maglatron

    Sallen Key Low Pass Filter, bandpass filter

    thanks mate also the six 100nf caps used for the filter and the two for the bypass caps for the TL074's and the one for the envelope detector are all and two for the REF GND circuits, oh dear think I found an error the caps I bought are 10nf not 100nf I've got two packs of greed film capacitors...
  10. Maglatron

    Sallen Key Low Pass Filter, bandpass filter

    surfing the web or an actual wave surfing. It'd be cool if you get to surf for a living!!
  11. Maglatron

    Sallen Key Low Pass Filter, bandpass filter

    another question I know how you said that 1 reference ground circuit could be enough for 4 entire filters, I used the 1st refenence ground for the amp filters and the LM3914's should that be ok or should the LM3914's have there own REF GND circuits? thanks
  12. Maglatron

    Sallen Key Low Pass Filter, bandpass filter

    might just build another circuit next to the existing one (mic preamp, amp and reference ground circuit) out of a TL074 and see if makes a difference if I give myself more space next time!
  13. Maglatron

    Sallen Key Low Pass Filter, bandpass filter

    so the C17 capacitor was backwards the resistor R21 is 500k going to dismantal the preamp and put together again also I wired the LM3914 bar graph LED's in bar graph mode too! made sure the mic was wired in correctly which it was when I flick the power switch all led's in the bar graph blink...
  14. Maglatron

    Sallen Key Low Pass Filter, bandpass filter

    also the resistor of the ref ground circuit is not 4.99k it's 4.6!
  15. Maglatron

    Sallen Key Low Pass Filter, bandpass filter

    so I run the sim and the R21 @ 470k resistor seems to run fine heres a screen shot tell me if you need higher resolution picture
  16. Maglatron

    Sallen Key Low Pass Filter, bandpass filter

    is there any way that I can test the mic-to-pre-amp, amp, filter and buffer before the lm3914 drivers I think they are set correctly because I checked and double checked also changed the R21 to a 4k7 because couldn't find a 500k and the R23 to 0.8meg actually might have been a 470k I will double...
  17. Maglatron

    Sallen Key Low Pass Filter, bandpass filter

    thanks
  18. Maglatron

    Sallen Key Low Pass Filter, bandpass filter

    ok thanks what time is it where you are in the world and one more thing how can I look at the voltage range coming from the filter? occiloscope? see ya!
  19. Maglatron

    Sallen Key Low Pass Filter, bandpass filter

    what does that mean? your phone playing up?
  20. Maglatron

    Sallen Key Low Pass Filter, bandpass filter

    what would the difference be if I used the standard ground connections instead of the ref ground's my thoughts are that the filters run on ref grounds so the out put will be between 6v and 8.4v from the signal from the filter and the standard ground would measure from 0v to 2.4v is that...
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