Help for Guitar Control

[splashsky]

I Built the circuit for Guitar Control (http://redcircuits.com/Page69.htm)

i Wanna use it for my Bass Guitar.

and it works fine... but there lots of clipping...(the breaking and cracking noise) mostly in the beginning... I checked all the connections and all the POT's but still the Clipping occurs....

and when i turn it off there's a buzz and then Becames silent...

other wise the sound is awesome... it rocks...

Can you

 

[audioguru2]

Hi Splashsky,
Welcome to our forum. ;D
The TL062 dual opamp has FET inputs like the TL072 dual opamp. They cause an opamp to suddenly invert its output polarity when the input voltage exceeds the common-mode voltage rating which is low in this circuit using only 9V for its supply.

The common-mode rating would be exceeded for loud guitar playing. If the battery voltage drops then the chopped sound will be worse.

Try the project with two 9V batteries in series making an 18V supply.
I would use an MC33172 or MC34072 dual opamp that won't cause this problem. You could try using older dual opamps like an MC1458 or an LM358 dual opamp. But these opamps use a higher battery current than the TL062 dual opamp in the project.

 

[splashsky]

Thanks for your prompt reply ...

Cracking, or breaking of sound and I checked for the battery (its brand new one)

 

[audioguru2]

there lots of clipping...(the breaking and cracking noise) mostly in the beginning...
I checked for the battery (its brand new one)

 

[splashsky]

If R12 and R13 are 220k instead of 22k then they would cause C7 to charge very slowly and cause distortion at the beginning and when the battery is turned off. Or if C7 is 1000uF instead of 100uF.

I Checked these value using multimeter it was OK... can i Try lesser value for (22 k resistor ) ? and the capacitor like 50uF.

The TL072 might have the same overload problem as the existing TL062 but the MC1458 and LM358 won't. The MC1458 and LM358 have the same pins numbers as the existing TL062 so try one. They will work without changing the circuit.

Will try the the other IC's

 

[splashsky]

Hi Splashsky,
welcome to our forum. ;D

Try the project with two 9V batteries in series making an 18V supply.
I would use an MC33172 or MC34072 dual opamp that won't cause this problem. You could try using older dual opamps like an MC1458 or an LM358 dual opamp. But these opamps use a higher battery current than the TL062 dual opamp in the project.

Thanks

If i subtitute the MC1458, or LM358

 

[audioguru2]

If i subtitute the MC1458, or LM358

 

[splashsky]

can i Try lesser value for (22 k resistor ) ? and the capacitor like 50uF?

The 22k resistors charge the 100uF cap in only 1.1 seconds after the battery is turned on. Lesser values will be quicker but it is quick enough now. If the values are 10 times higher then there will be crackling at the beginning for 11 seconds.

Is there crackling if you play softly?

 

[audioguru2]

If the crackling problem is caused by the inputs of the TL062 opamps being overloaded then playing the guitar softly, using an 18V supply for them or using the other opamps I have listed will fix it.

The 22k resistors charge the 100uF capacitor in 1.1 seconds which should be quick enough. Does the crackling in the beginning last for longer than only 1.1 seconds after the battery is turned on?

The volume of the sound should not change by itself. I think something must be disconnected in the incomplete circuit that causes the DC voltage at the output of an opamp to change with the signal.

What is this circuit driving? Its load should be 10k ohms or higher or the volume control will be burnt and the opamp will overheat.

 

[splashsky]

If the crackling problem is caused by the inputs of the TL062 opamps being overloaded then playing the guitar softly, using an 18V supply for them or using the other opamps I have listed will fix it.

The 22k resistors charge the 100uF capacitor in 1.1 seconds which should be quick enough. Does the crackling in the beginning last for longer than only 1.1 seconds after the battery is turned on?

yes its more than 1.1 like for some times its like for the whole time the battery is on..

What is this circuit driving? Its load should be 10k ohms or higher or the volume control will be burnt and the opamp will overheat.

the opamp did not heat up...

 

[splashsky]

Almost all the problem was solved Thanks

but only the hum is there in the End, like when i turn off the battery.