filters in modulation
Posted: 20 Jul 2018, 23:54
Hello.
At the moment I'm studying how modulation works and was interested in some nuances in MXR schemes
1) MXR Chorus (bottom image) uses 2 halves of U1 as input buffer and active filter.
I did a simulation and realized that you can get a similar result using only 1 half of an operational amplifier, as is done in the MXR Flanger scheme(upper image), just change several ratings to get a similar filter.
Is there any advantage in the form of a separate filter and input buffer against the classic non-inverting amplifier in the MXR flanger circuit, both have high input impedance and the same cutoff frequency, what reason to use more components?
2) Regarding the Flanger. In many Flanger circuits, I see an inverting amplifier with a symmetrical clipping(U2).
What role does it play in this type of effect. I saw a similar cascade in the BOSS BF-2 and Ibanez FL9 & Airplane.
I understand that it limits the peaks of the signal, but from a technical point of view I do not understand why this is done. Clipping and feedback is the main difference between Flanger and Chorus (apart from delay time)?
Why is this amplifier inverting?
Why change the phase, because you can just put a non-inverting amplifier.
3) What does the Manual controller do?
Does it change the frequency on which the LFO works? Or does it change the delay time?
4) I'm confused about what Q1 + Q2 + Q3 + Q4 do.
Please tell us in detail their principle of operation or what is the name of this design.
At the moment I'm studying how modulation works and was interested in some nuances in MXR schemes
1) MXR Chorus (bottom image) uses 2 halves of U1 as input buffer and active filter.
I did a simulation and realized that you can get a similar result using only 1 half of an operational amplifier, as is done in the MXR Flanger scheme(upper image), just change several ratings to get a similar filter.
Is there any advantage in the form of a separate filter and input buffer against the classic non-inverting amplifier in the MXR flanger circuit, both have high input impedance and the same cutoff frequency, what reason to use more components?
2) Regarding the Flanger. In many Flanger circuits, I see an inverting amplifier with a symmetrical clipping(U2).
What role does it play in this type of effect. I saw a similar cascade in the BOSS BF-2 and Ibanez FL9 & Airplane.
I understand that it limits the peaks of the signal, but from a technical point of view I do not understand why this is done. Clipping and feedback is the main difference between Flanger and Chorus (apart from delay time)?
Why is this amplifier inverting?
Why change the phase, because you can just put a non-inverting amplifier.
3) What does the Manual controller do?
Does it change the frequency on which the LFO works? Or does it change the delay time?
4) I'm confused about what Q1 + Q2 + Q3 + Q4 do.
Please tell us in detail their principle of operation or what is the name of this design.