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Help on a divide and blend circuit - wet and dry - tl072 Answered


i want to build a "divide and blend" circuit with one potentiometer to blend between a dry and wet signal, the source will only be audio and the wet signal will be a clone of the MS-20 filter.

my knowledge of electronic is almost zero... so i looked on different circuits and tried to adapt to what i want, but i need you guys to confirm if what i've designed works? do you see any problem? to you have any suggestions?

thank you very much


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Jack A Lopez
Jack A Lopez

2 years ago

The way you can discover if your circuit works is by testing it yourself.

Moreover, you should try to get each little sub-circuit working first, e.g. each follower, adder, filter, etc, for to confirm that each little sub-circuit is doing what it is supposed to be doing.

Just looking at what you have drawn, it is not obvious to me whether this circuit will work or not.

Although, I suspect that it will not work, and the reason why is because I do not see what is determining the DC output, of each of those two op-amps.

It seems to me like there should be something to force the DC output to a particular value, like maybe halfway in between the high rail (pin 8) and the low rail (pin 4).

I think the usual trick for this is a voltage divider, perhaps made of two 100 K resistors, with the center of the divider tied to the non-inverting input on the first op-amp (pin3).

Then repeat that trick, with another voltage divider made of two 100 K resistors, connected to the non-inverting input of the second op-amp (pin 5).

Do you know what I mean? Maybe I should draw you a picture of it?