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

[fbonito]

hello,
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

 

[rayma]

hello,
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.

The -9V op amp pin #4 and the -9V battery terminal both should be grounded.
Also op amp pin #3 should go through a 100k-1M resistor to op amp pin #5.
On the input side of C1 there should be a 1M resistor to ground.

You also will want a power switch, wired in series with the +9V battery terminal,
before it connects to anything else.

 

[fbonito]

Hi Rayma,


Thank you for question quick reply/suggestions.


I just have one question, can you clarify why to connect the pin #3 and#5 with a resistor?


Thanks

 

[rayma]

why to connect the pin #3 and#5 with a resistor?

This is called a single supply circuit. The + op amp inputs must be biased
to half the DC supply in order for them to work correctly.

The first op amp + input (pin #3) must be referred to half of the DC supply voltage,
which is at the junction of the two 100k resistors (R9 and R10).

The second op amp + input (pin #5) is already connected this way,
and the first op amp + input (pin #3) can be connected to it through a resistor.
The added (100k-1M) resistor also serves as the input impedance.

 

[fbonito]

Thanks. I will update the circuit and upload the revised version

 

[fbonito]

hello,


here is the revised circuit layout, hope that i'm getting there 🙂