Sallen Key Low Pass Filter, bandpass filter

[Maglatron]

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 I think that they might be the same BUT can you test for capacitancebecause one pack might be the correct value other wise I'll get some more anyway the original question was going to be are film capacitors good to use?? thanks

 

[Maglatron]

got the new ones ordered now coming monday!!

 

[Maglatron]

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

 

[Delta Prime]

doh palm hits forehead!

 

[Maglatron]

exactly like that lol

 

[Maglatron]

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!

 

[Maglatron]

film is fine!!

Hello,

Most times film capacitors will have a better quality as ceramic capacitors.

Bertus

 

[Maglatron]

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

 

[bertus]

Hello,

The following picture might help you reading the resistor color codes:

Bertus

 

[Maglatron]

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 the large proto board and think I can avoid some of the issues I come across first time round!

 

[Maglatron]

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

 

[Maglatron]

so upon further inspection I think it's going to be ok!!

 

[Maglatron]

UPDATE: I've replaced the 10nF with 100nF caps and not instead of a little flicker and all off, the LED's are all ON, on the first column - and bright too maybe need to tweak, any ideas guys thank you, I feel like progress is being made!!

 

[bertus]

hello,

measure the voltage on the inputs of the lm3914's (pin 5)

bertus

 

[Maglatron]

ok, will it not be fluctuating too fast?? thanks. will that be measured from the pin 5 and GND or pin 5 and REF GND Also next time I get on it is tomorrow now! what I'm getting from it is that the 45Hz is getting through because the LED's are lighting but the lower and upper thresholds might be ascew atm

 

[bertus]

hello,

when you measure between pin 5 and ref, you should measure a value between 0 an 2.4 volts for 0 to all leds.

bertus

 

[Maglatron]

sorry I did not get that last bit! thanks

0 to all leds.

 

[bertus]

hello,

at 0 volts no led should burn.
at 2.4 volts all leds should burn.

bertus

 

[Maglatron]

ok so I'll get some results for you tomorrow I'm thinking as a possibility that I may have shorted the input to pin 5 to 12volt what would this do, don't think it is the case but... would the all LED's be lit

 

[bertus]

hello,

a short between pin 5 (input) and pin 6 (high end) would also cause all leds to burn.

bertus