Sallen Key Low Pass Filter, bandpass filter

[Maglatron]

Ok thats good to know that 2.4 is quite high, there is a pre-amp, which is an amp, from the mic to the filters -no gain in the filters though.
By rectifier do you mean the envelope detector? Rx does not have a value at the moment what should it be set at? Ok another stage, amplifier, I'm looking into now but I will build without to start with and then put in if needs be!

 

[Maglatron]

are the capacitors tantalum and what is the working voltage for them? apart from the C101M 10uF electrolytic. I am now ordering the parts so I need to know as soon as possible

 

[Maglatron]

would these in 100nF suffice?

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[Maglatron]

can I use the op-amps in the filter wizard to increase gain ratio, (output to input ratio)

 

[bertus]

Hello,

In filterwizard you can set a gain.
The gain will be given in dB.
3 dB = 2 times, 10 dB = 10 times.

Bertus

 

[Maglatron]

Ok cool can you tell me the value of Rx and tell me if those caps in the link will be good enough (green) please getting parts ordered at 4 brittish time

Mylar Capacitors Polyester Film 100V 5%​

 

[bertus]

Hello,

Those caps will be fine for the filters.
Also look for the other filters, so you have one time the ordering costs.

As for the 10 uF , electrolitic or tantal can be used.

Bertus

 

[Maglatron]

other filters? I was going to go with the TL074, I need dip package!

 

[bertus]

Hello,

You will also need to get the values for the other frequency filters.
As far as i know you wanted 16 bands.

Bertus

 

[Maglatron]

ok I see now, now for some paper work!

 

[Maglatron]

ah just as I thought I had it hufff I'm having trouble, dont suppose you can help me with the existing 15 filters I managed to do up to 720Hz the filter used in all of them were the AD8657 which I think I can swap out for the TL074 quad

 

[Maglatron]

 

[Maglatron]

I think the stopband and the bandpass need to be the same ratio as the 45Hz (and oh yeah I'm starting at 45Hz now because thats where I start to hear)

 

[bertus]

Hello,

You could also use a low pass for the first filter and a high pass for the last filter.
All other filters can be band pass.

Bertus

 

[Maglatron]

ok, does the -dB in the passband control the filter to pass frequency with volume of the signal?

 

[bertus]

Hello,

No, the topline with gain controls the volume.
Leave the second line at - 3dB.

Bertus

 

[Maglatron]

ok I see the left numbers shift when altering gain, and also the 8 hz is the width of the passband in this case (4Hz either side of the centre) as the frequency gets higher does this number need to increase? so how do you set stopband properly? (I can adjust the centre frequency)
like what are the rules to follow so that I can create working passband filters I took on board about what you said with the low pass and high pass filters but I think I should master it like this first, thank yo just noticed the little question marks next to the settings I shall read up on them now thanks

 

[Maglatron]

I don't understand the following!
This is the range of frequencies you want to let through. Define this region by entering the circuit gain at the passband frequencies, the frequency cutoff, and the attenuation you prefer at this frequency cutoff.
Attenuation is relative to the gain entered. For example, if you enter 20 dB for the gain and attenuation of -3 dB, then the tool attempts to set the passband cutoff frequency at 17 dB
What gain would you reccomend if any

This is the range of frequencies you want to reject.
The attenuation is relative to the circuit gain. For example if you enter 20 dB for the gain and an attenuation of -35 dB, then the tool attempts to set the stopband frequency at -15 dB.

I only think I've gone a nd sussed it ratio, from centre frequency to input frequency pass band ie 45:8
then set the 45 to 16000 and the so the input to the bandpass field is 2844.4
And then the ratio of the stop band to the passband 30:8
set the 8 to 2844.4 and the stop band is at 10666.5
This give the exact same curve as the 45Hz and it's for 16kHz
The op-amps used for this one is LT6220 can you get these in quad dip packaging from mouser?????????
OR suggest one that does come in dip packageing preferably quad or 6 in one??

 

[bertus]

Hello,

Read the remarks I made on the picture in post #81.

Bertus

 

[Maglatron]

Ok thanks so like this!!;